**3.1 Effects of interventions on written composition performance**

We first present the results relating to products written on the cognitive processes activated in the drafting of the texts.

#### **Product Measures**

Multivariate contrasts of variance showed statistically significant results and a large size effect for all measures based on the text and the reader, as shown in Table 6.

Between-effects tests show statistically significant differences in text-based indicators of productivity [F (3, 108) = 7.169, p <.001, η2 = .166], referential coherence [F (3, 108) = 11.241, p<.001, η2= .238], relational coherence [F (3, 108) = 24.245, p <.001, η2 = .402], overall consistency [F(3, 108) = 18 506 , p <.001, η2 = .340], other measures of consistency [F (3, 108) = 11.927, p <.001, η2 = .249] and overall structure [F (3, 108) = 38 367, p <.001, η2 = .516], as well as structure [F (3, 108) = 40.055, p <.001, η2 = .527], consistency [F (3, 108 )=14701, p <.001, η2 = .290], quality reader-based indicators [F (3, 108) = 11.606, p <.001, η2 = .244] and the resulting total [F(3, 108) = 22.842, p <.001, η2 = .388] in all cases, with a large size effect.

Post-hoc analyses have shown statistically significant changes across groups following the implementation of different instructional methods. The data is shown in the Table 7.

This analysis shows a significant improvement in all text-based measures and in the reader of the groups who developed the specific interventions for the EFP and PRO groups, compared to CO and PAD groups.

Three months after the implementation of the various forms of intervention, we detected that in groups where actual instruction had taken place there was a partial maintenance of the gains resulting from the interventions. In these cases, as in the case of text-based measures, although there were significant decreases between the post-test and follow-up in overall coherence and other consistency items, there was significant improvement vis-à-vis the initial situation (pretest). Regarding structure, the gains following the implementation of the different interventions were almost entirely maintained within the three months following the intervention. As for reader-based measures, we detected maintenance and even further development compared to the post-test.

The application of learning to other types of text was also corroborated. In this case, we saw a considerable improvement in the follow-up compared to the pretest (p = <.001) in the EFP and PRO groups, compared to the PAD group in the *other coherence* text-based measures (pretest comparison-contrast: MPRO = 1.2, MEFP = 0.9 and MPAD = 1.2; coherent storyline: MPRO = 2.2, MEFP = 2.8 and MPAD = 1.1) and *structure* (pretest: MPRO = 1.1, MEFP = 1.1 and MPAD = 1.3;

Table 6. Results of repeated factorial measures designed 4 x 2, measures of written product

118 Learning Disabilities

First, we conducted an analysis of variance with repeat measures of 4 x 2 taking the repeated measure time (pre/post-test) as inter-subjects factor and the experimental group students

Second, we conducted an analysis of the measures repeated 3 X 3. We considered the group as intersubject factor (PRO, EFP and PAD, as the CO group was not evaluated after three months due to lack of availability) and as intra-subject factor the repeated pretest, posttest

We first present the results relating to products written on the cognitive processes activated

Multivariate contrasts of variance showed statistically significant results and a large size

Between-effects tests show statistically significant differences in text-based indicators of productivity [F (3, 108) = 7.169, p <.001, η2 = .166], referential coherence [F (3, 108) = 11.241, p<.001, η2= .238], relational coherence [F (3, 108) = 24.245, p <.001, η2 = .402], overall consistency [F(3, 108) = 18 506 , p <.001, η2 = .340], other measures of consistency [F (3, 108) = 11.927, p <.001, η2 = .249] and overall structure [F (3, 108) = 38 367, p <.001, η2 = .516], as well as structure [F (3, 108) = 40.055, p <.001, η2 = .527], consistency [F (3, 108 )=14701, p <.001, η2 = .290], quality reader-based indicators [F (3, 108) = 11.606, p <.001, η2 = .244] and the resulting total

Post-hoc analyses have shown statistically significant changes across groups following the

This analysis shows a significant improvement in all text-based measures and in the reader of the groups who developed the specific interventions for the EFP and PRO groups,

Three months after the implementation of the various forms of intervention, we detected that in groups where actual instruction had taken place there was a partial maintenance of the gains resulting from the interventions. In these cases, as in the case of text-based measures, although there were significant decreases between the post-test and follow-up in overall coherence and other consistency items, there was significant improvement vis-à-vis the initial situation (pretest). Regarding structure, the gains following the implementation of the different interventions were almost entirely maintained within the three months following the intervention. As for reader-based measures, we detected maintenance and

The application of learning to other types of text was also corroborated. In this case, we saw a considerable improvement in the follow-up compared to the pretest (p = <.001) in the EFP and PRO groups, compared to the PAD group in the *other coherence* text-based measures (pretest comparison-contrast: MPRO = 1.2, MEFP = 0.9 and MPAD = 1.2; coherent storyline: MPRO = 2.2, MEFP = 2.8 and MPAD = 1.1) and *structure* (pretest: MPRO = 1.1, MEFP = 1.1 and MPAD = 1.3;

implementation of different instructional methods. The data is shown in the Table 7.

belonged to (EFP, PRO, PAD, CO) as inter-factor.

**3.1 Effects of interventions on written composition performance**

effect for all measures based on the text and the reader, as shown in Table 6.

[F(3, 108) = 22.842, p <.001, η2 = .388] in all cases, with a large size effect.

and follow-up measures.

in the drafting of the texts.

compared to CO and PAD groups.

even further development compared to the post-test.

**Product Measures**

Preventing Children's Writing Difficulties Through Specific Intervention in the Home 121

respectively. However, the pre/post differences in interaction with the intervention in the trial of inter-subject effects was not statistically significant for mechanical [*F* (3, 108) = 1.479, *p* = .224, η2 *=* .039] nor fundamental indicators [*F* (3, 108) = 2.330, *p* = .078, η2 *=* .061] so we chose to individually analyze some items of interest. In this case, significant differences were found in item number 11 - organization of ideas into paragraphs [*F* (3, 108) = 6.277, *p* = .001, η2*=*.148]. The inter-subject effects test confirmed this [*F* (3, 108) = 4.329, *p* = .006, η2 *=* .107] and the post-hoc indicated that the only differences were between the CO and the EFP (p=.032), PAD (p = .043) and PRO (p = .035) groups. These groups somewhat improved their writing practices in all measures (pretest, Mco = 60.1, MEFP = 62.4, MPAD = 70.7 y MPRO = 67.4;

Three months after completion of the intervention, in general there have not been

This time we designed 2x2 repeated measures because only PAD and EFP students completed this scale. Thus, the intra-subject factor considered as the repeated measure was the pre/post-test and the inter-subject factor was the experimental group students belonged to.

Multivariate contrasts showed no statistically significant results for any of the FAOP-PRAES variables. They did, however, for three IM FAOP - Total: home involvement [*F* (1.47)=4.529, *p* = .039, η2 = .088], school involvement [*F* (1.47) = 4.529, *p* = .039, η2 = .088] and total

The intersubject effects tests show statistically significant differences in indicators of home involvement [*F* (1.47) = 3.985, *p* = .052, η2 = .078], in school [*F* (1.47) = 8.427*, p* = .006, η2=.152] and [*F* (1.47) = 6.405, *p* = .015, η2 = .120], with medium/large size effects. Such group

Home School Total

Fig. 1. Differences in FAOP-IM measures between groups at the time of evaluation

EFP PAD EFP PAD

Pretest Post-test

statistically significant changes in any of the motivational-emotional elements.

post-test, Mco = 47.7, MEFP = 84.1, MPAD = 74.7 y MPRO = 76.03).

**3.2.1 Family opinions: Implication and writing practice**

involvement [ *F* (1,47) = 8.720, *p* = .005, η2 = .156].

differences favor the EFP group, as evidenced in Figure 1.

flow of argument: MPRO = 2.3, MEFP = 2.8 and MPAD = 1.5) and in all the reader-based measures including the total (pretest comparison-contrast: MPRO = 4.2, MEFP=.4 and MPAD = 3.8; flow of argument: MPRO = 6.7, MEFP = 8.7 and MPAD = 3.2).

Table 7. Post-hoc contrasts in the textual product measures

#### **Process measures**

Following the process measures, multivariate contrasts and inter-subject effects tests show statistically significant differences in overall task frequency [*F*(3, 108) = 3.409, *p* = .020, η2=.087], frequency of making an outline or draft [*F*(3, 108) = 4.250, *p* = .007, η2 = .106] and percentage of time thinking about ideas [*F*(3, 108) = 4141*, p* = .008, η2 = .103 ].

The post-hoc analysis showed a significant improvement in the groups that received explicit instruction in writing processes (EFP y PRO) compared to the CO and PAD. Thus, the EFP group increased the total task frequency compared to CO (p = .022; pretest: MEFP = 15.7 and MCO = 19.7; post-test: MEFP = 25.8 and MCO = 14.2) and in time preparing a draft (pretest: MEFP= 0.07 and MCO = 2.1; post-test: MEFP = 5.5 and MCO = 0.3). This general increase in the time spent drafting was also significant among the PRO and CO groups (p=.032; pretest: MPRO = 0 and MCO = 2.1; post-test: MPRO = 6.3 and MCO = 0.3).

#### **3.2 Effects of interventions on the motivational and contextual elements**

Regarding attitudes, multivariate contrasts do not show statistically significant results.

When looking at attributions, on the other hand, the results were statistically significant regarding time-intervention interaction in the failure-effort attributional pattern [*F* (3, 108)=3.545, p = .017; *η2 =* .090]. The inter-subject effects test was also statistically significant [*F* (3, 108) = 2.800, *p* =.044, η2 *=* .073] and post-hoc contrasts showed differences very close to statistical significance between EFP and PAD groups (p = .059), both showing a decrease from pretest to post-test (pretest, MEFP= 11.40 vs. MPAD= 9.04; post-test, MEFP = 9.96 vs. MPAD=. 80).

As for self-efficacy, multivariate contrasts show statistically significant results in the timetreatment interaction in both areas – mechanical [*F* (3, 108) = 3.453, *p* = .019, η2 *=* .088] and fundamental [*F* (3, 108) = 6.560, *p* = <.001, η2 *=* .154] - with medium and large size effects,

flow of argument: MPRO = 2.3, MEFP = 2.8 and MPAD = 1.5) and in all the reader-based measures including the total (pretest comparison-contrast: MPRO = 4.2, MEFP=.4 and MPAD =

*Variables EFP vs. PRO EFP vs. CO EFP vs. PAD PRO vs. CO PRO vs. PAD PAD vs. CO*

Productivity n.s. .008 .028 .009 .035 n.s. C. Referential n.s. .001 .017 <.001 .003 n.s. C. Relational n.s. <.001 <.001 <.001 <.001 n.s. C. total n.s. <.001 <.001 <.001 <.001 n.s. Others C. n.s. <.001 .017 <.001 .022 n.s. Structure n.s. <.001 <.001 <.001 <.001 n.s.

Structure n.s. <.001 <.001 <.001 <.001 n.s. Coherence n.s. <.001 <.001 <.001 .003 n.s. Quality n.s. .024 .018 <.001 <.001 n.s. Total n.s. <.001 <.001 <.001 <.001 n.s.

Following the process measures, multivariate contrasts and inter-subject effects tests show statistically significant differences in overall task frequency [*F*(3, 108) = 3.409, *p* = .020, η2=.087], frequency of making an outline or draft [*F*(3, 108) = 4.250, *p* = .007, η2 = .106] and percentage of

The post-hoc analysis showed a significant improvement in the groups that received explicit instruction in writing processes (EFP y PRO) compared to the CO and PAD. Thus, the EFP group increased the total task frequency compared to CO (p = .022; pretest: MEFP = 15.7 and MCO = 19.7; post-test: MEFP = 25.8 and MCO = 14.2) and in time preparing a draft (pretest: MEFP= 0.07 and MCO = 2.1; post-test: MEFP = 5.5 and MCO = 0.3). This general increase in the time spent drafting was also significant among the PRO and CO groups (p=.032; pretest:

3.8; flow of argument: MPRO = 6.7, MEFP = 8.7 and MPAD = 3.2).

Table 7. Post-hoc contrasts in the textual product measures

time thinking about ideas [*F*(3, 108) = 4141*, p* = .008, η2 = .103 ].

MPRO = 0 and MCO = 2.1; post-test: MPRO = 6.3 and MCO = 0.3).

**3.2 Effects of interventions on the motivational and contextual elements**

Regarding attitudes, multivariate contrasts do not show statistically significant results.

When looking at attributions, on the other hand, the results were statistically significant regarding time-intervention interaction in the failure-effort attributional pattern [*F* (3, 108)=3.545, p = .017; *η2 =* .090]. The inter-subject effects test was also statistically significant [*F* (3, 108) = 2.800, *p* =.044, η2 *=* .073] and post-hoc contrasts showed differences very close to statistical significance between EFP and PAD groups (p = .059), both showing a decrease from pretest to post-test (pretest, MEFP= 11.40 vs. MPAD= 9.04; post-test, MEFP = 9.96 vs.

As for self-efficacy, multivariate contrasts show statistically significant results in the timetreatment interaction in both areas – mechanical [*F* (3, 108) = 3.453, *p* = .019, η2 *=* .088] and fundamental [*F* (3, 108) = 6.560, *p* = <.001, η2 *=* .154] - with medium and large size effects,

*Text-based measures*

*Reader-based measures*

**Process measures**

MPAD=. 80).

respectively. However, the pre/post differences in interaction with the intervention in the trial of inter-subject effects was not statistically significant for mechanical [*F* (3, 108) = 1.479, *p* = .224, η2 *=* .039] nor fundamental indicators [*F* (3, 108) = 2.330, *p* = .078, η2 *=* .061] so we chose to individually analyze some items of interest. In this case, significant differences were found in item number 11 - organization of ideas into paragraphs [*F* (3, 108) = 6.277, *p* = .001, η2*=*.148]. The inter-subject effects test confirmed this [*F* (3, 108) = 4.329, *p* = .006, η2 *=* .107] and the post-hoc indicated that the only differences were between the CO and the EFP (p=.032), PAD (p = .043) and PRO (p = .035) groups. These groups somewhat improved their writing practices in all measures (pretest, Mco = 60.1, MEFP = 62.4, MPAD = 70.7 y MPRO = 67.4; post-test, Mco = 47.7, MEFP = 84.1, MPAD = 74.7 y MPRO = 76.03).

Three months after completion of the intervention, in general there have not been statistically significant changes in any of the motivational-emotional elements.

#### **3.2.1 Family opinions: Implication and writing practice**

This time we designed 2x2 repeated measures because only PAD and EFP students completed this scale. Thus, the intra-subject factor considered as the repeated measure was the pre/post-test and the inter-subject factor was the experimental group students belonged to.

Multivariate contrasts showed no statistically significant results for any of the FAOP-PRAES variables. They did, however, for three IM FAOP - Total: home involvement [*F* (1.47)=4.529, *p* = .039, η2 = .088], school involvement [*F* (1.47) = 4.529, *p* = .039, η2 = .088] and total involvement [ *F* (1,47) = 8.720, *p* = .005, η2 = .156].

The intersubject effects tests show statistically significant differences in indicators of home involvement [*F* (1.47) = 3.985, *p* = .052, η2 = .078], in school [*F* (1.47) = 8.427*, p* = .006, η2=.152] and [*F* (1.47) = 6.405, *p* = .015, η2 = .120], with medium/large size effects. Such group differences favor the EFP group, as evidenced in Figure 1.

Fig. 1. Differences in FAOP-IM measures between groups at the time of evaluation

Preventing Children's Writing Difficulties Through Specific Intervention in the Home 123

as the few previous localized empirical studies in this area had shown, although these mostly focused on initial stimulation or in recovering less complex elements from long-term memory (Axford, 2007; Feiler, 2003; Saint Lauren & Giasson, 2005) and did not systematically

This intervention program, which addressed the cognitive aspect specifically, we can confirm encouraged in both groups of students subjected to systematic instruction (EFP and PRO) the efficient activation of the psychological processes involved in written composition and was conducive to greater efficiency in this task, although it had a greater impact on the planning process specifically. This again confirms the potential for parents, not only to promote ways of helping their children improve their textual production, but also for advising them on the use of cognitive strategies that enable them to effectively activate the

In terms of motivational elements, we have to acknowledge that the program did not produce statistically significant changes in attitudes toward writing in any context, nor has it stimulated more adaptive attributional patterns. However, in the latter case, both peer groups (EFP and PRO) show a positive trend apparent in the increase of attributions to internal factors (effort) and the decrease in external factors (luck). This is possibly due to the stability of these personality constructs and the resulting difficulty in modifying them in a few sessions. The difficulty of optimizing them has been found in specific interventions aimed at motivation for writing (Garcia & de Caso, 2006). Moreover, with respect to efficacy, although there was an increase in the EFP and PRO groups compared with the PAD and CO groups, neither reached statistical significance. Perhaps this result is a consequence of the evolutionary trend that the development of self-efficacy follows, which is exemplified by the overestimation of students' writing ability in the initial stages of education, such as Primary

Thirdly, as to whether increasing parental involvement in homework is sufficient to improve children's outcomes or whether prior training is required to enable them to do so, the results conclude that training contributes to a significantly higher level of success than just natural collaboration, as evidenced by the comparison of the EFP and PAD groups.

As for the parent training program, it has proven very effective and has managed to prepare parents to enhance the development of their children's written composition, not only by participating as role models or providing materials and resources, but also specifically instructing them in the higher-order cognitive processes that make up that skill through the

Despite the limitations of this study we can confirm its positive results. The limitations are mainly related to low family involvement and high parents and teacher motivation to engage in instruction, which might account for the degree of positive effect of the program in encouraging the review process or stimulating motivational elements. Thus, the effectiveness of the intervention program to enhance improvements in students' written products in the third cycle of Primary education, its stability and application to other forms of writing, as well as to encourage the activation of the mental processes responsible for efficient text processing, especially in regard to planning, are all confirmed. Similarly, we conclude that the family context, and parents in particular, perfectly complement the teaching of writing. Their potential to stimulate their children's writing competence through

address higher-order processes in older children, which was the focus of our work.

higher cognitive processes involved in writing.

(Pajares, Valiente, & Cheong, 2006 ).

use of homework.

#### **4. Discussion and conclusions**

The new European education guidelines establish the need to stimulate the development of students' skills (Llach & Alsina, 2009; Fernández, 2007; Muñoz, 2008) and stress the importance of compulsory education specifically in the promotion of communicative competence in its oral reading and writing forms (Pérez & Zayas, 2007; LOE, 2006). Nevertheless, it is common for formal education to address the written aspect of this competence in a less profound manner than the other dimensions. The prevailing psycholinguistic teaching trends focus on aspects with lower cognitive load, at the expense of communicative approaches (Clemente, Ramínez, & Sanchez, 2010; Fabregat, 2009; Gilbert & Graham, 2010; Lecuona, et al., 2003). The other main context of children's learning - the family – which could also help optimize the student's written communication skills (Axford, 2007; Cutler & Graham, 2008; Feiler, 2003; Jones & Christensen, 1999; Rasinki & Padaka, 2009; Reyes, et al., 2007; Saint Laurent & Giasson, 2005), also shows little interest in developing them. Thus, the consideration that composing written texts is a complex process that requires instruction and practice set in context and motivation to promote and facilitate its assimilation (de Caso & García, 2006a; de Caso & García, 2006b) led to our interest in finding whether the teaching of written composition through psycho-communicative methods in different educational contexts could redress the imbalance and fill the gaps resulting from the incomplete traditional educational approach. Based on this perspective, we developed this research, which sought to test the differential effectiveness of a writing intervention program, implemented in two different contexts (school and home) and by two different educational figures (parents-teachers), to optimize students' writing competence. We also sought to determine families' ability to carry out this type of instruction and indirectly validate the effectiveness of a training program designed and implemented to prepare them for this. The results obtained in the course of this research project lead us to several relevant conclusions.

First, the instructional program designed to address the teaching of written composition focused on the product and process, was highly effective in promoting the improvement of the quality of pupils' written texts. This was as expected, considering that the effectiveness of these interventions had been tested by this research team in previous studies (Arias & García, 2007; García, Fidalgo, & Robledo, 2010; Fidalgo, García, Torrance, & Robledo, 2009; Fidalgo, Torrance, & García, 2008). However, this study's main contribution is the finding that the context and the figures of implementation produce no differential effect on program effectiveness. Both family members at home (EFP group) and faculty in the classroom (PRO group) successfully carried out instructional sessions with children, passing on knowledge and methods useful to significantly enhance their writing proficiency when compared to control groups (CO and PAD). Thus, in addition to ratifying the internal efficiency of the program, we can confirm the potential of both environments to optimize the learning of writing, as well as similarities in the teaching capacities of teachers and parents. In both cases, the teaching carried out resulted in students producing better structured, more consistent and higher quality texts. Moreover, in both cases these improvements were maintained over time and, most noticeably, were applied across different text typologies.

Families, despite not being teaching professionals with relevant training have specific advantages (interest in their children's education, availability, direct contact with the child, bonding, etc.). They can therefore contribute very effectively to the optimization of writing,

The new European education guidelines establish the need to stimulate the development of students' skills (Llach & Alsina, 2009; Fernández, 2007; Muñoz, 2008) and stress the importance of compulsory education specifically in the promotion of communicative competence in its oral reading and writing forms (Pérez & Zayas, 2007; LOE, 2006). Nevertheless, it is common for formal education to address the written aspect of this competence in a less profound manner than the other dimensions. The prevailing psycholinguistic teaching trends focus on aspects with lower cognitive load, at the expense of communicative approaches (Clemente, Ramínez, & Sanchez, 2010; Fabregat, 2009; Gilbert & Graham, 2010; Lecuona, et al., 2003). The other main context of children's learning - the family – which could also help optimize the student's written communication skills (Axford, 2007; Cutler & Graham, 2008; Feiler, 2003; Jones & Christensen, 1999; Rasinki & Padaka, 2009; Reyes, et al., 2007; Saint Laurent & Giasson, 2005), also shows little interest in developing them. Thus, the consideration that composing written texts is a complex process that requires instruction and practice set in context and motivation to promote and facilitate its assimilation (de Caso & García, 2006a; de Caso & García, 2006b) led to our interest in finding whether the teaching of written composition through psycho-communicative methods in different educational contexts could redress the imbalance and fill the gaps resulting from the incomplete traditional educational approach. Based on this perspective, we developed this research, which sought to test the differential effectiveness of a writing intervention program, implemented in two different contexts (school and home) and by two different educational figures (parents-teachers), to optimize students' writing competence. We also sought to determine families' ability to carry out this type of instruction and indirectly validate the effectiveness of a training program designed and implemented to prepare them for this. The results obtained in the course of this research project lead us to

First, the instructional program designed to address the teaching of written composition focused on the product and process, was highly effective in promoting the improvement of the quality of pupils' written texts. This was as expected, considering that the effectiveness of these interventions had been tested by this research team in previous studies (Arias & García, 2007; García, Fidalgo, & Robledo, 2010; Fidalgo, García, Torrance, & Robledo, 2009; Fidalgo, Torrance, & García, 2008). However, this study's main contribution is the finding that the context and the figures of implementation produce no differential effect on program effectiveness. Both family members at home (EFP group) and faculty in the classroom (PRO group) successfully carried out instructional sessions with children, passing on knowledge and methods useful to significantly enhance their writing proficiency when compared to control groups (CO and PAD). Thus, in addition to ratifying the internal efficiency of the program, we can confirm the potential of both environments to optimize the learning of writing, as well as similarities in the teaching capacities of teachers and parents. In both cases, the teaching carried out resulted in students producing better structured, more consistent and higher quality texts. Moreover, in both cases these improvements were maintained over time and, most noticeably, were applied across different text typologies.

Families, despite not being teaching professionals with relevant training have specific advantages (interest in their children's education, availability, direct contact with the child, bonding, etc.). They can therefore contribute very effectively to the optimization of writing,

**4. Discussion and conclusions**

several relevant conclusions.

as the few previous localized empirical studies in this area had shown, although these mostly focused on initial stimulation or in recovering less complex elements from long-term memory (Axford, 2007; Feiler, 2003; Saint Lauren & Giasson, 2005) and did not systematically address higher-order processes in older children, which was the focus of our work.

This intervention program, which addressed the cognitive aspect specifically, we can confirm encouraged in both groups of students subjected to systematic instruction (EFP and PRO) the efficient activation of the psychological processes involved in written composition and was conducive to greater efficiency in this task, although it had a greater impact on the planning process specifically. This again confirms the potential for parents, not only to promote ways of helping their children improve their textual production, but also for advising them on the use of cognitive strategies that enable them to effectively activate the higher cognitive processes involved in writing.

In terms of motivational elements, we have to acknowledge that the program did not produce statistically significant changes in attitudes toward writing in any context, nor has it stimulated more adaptive attributional patterns. However, in the latter case, both peer groups (EFP and PRO) show a positive trend apparent in the increase of attributions to internal factors (effort) and the decrease in external factors (luck). This is possibly due to the stability of these personality constructs and the resulting difficulty in modifying them in a few sessions. The difficulty of optimizing them has been found in specific interventions aimed at motivation for writing (Garcia & de Caso, 2006). Moreover, with respect to efficacy, although there was an increase in the EFP and PRO groups compared with the PAD and CO groups, neither reached statistical significance. Perhaps this result is a consequence of the evolutionary trend that the development of self-efficacy follows, which is exemplified by the overestimation of students' writing ability in the initial stages of education, such as Primary (Pajares, Valiente, & Cheong, 2006 ).

Thirdly, as to whether increasing parental involvement in homework is sufficient to improve children's outcomes or whether prior training is required to enable them to do so, the results conclude that training contributes to a significantly higher level of success than just natural collaboration, as evidenced by the comparison of the EFP and PAD groups.

As for the parent training program, it has proven very effective and has managed to prepare parents to enhance the development of their children's written composition, not only by participating as role models or providing materials and resources, but also specifically instructing them in the higher-order cognitive processes that make up that skill through the use of homework.

Despite the limitations of this study we can confirm its positive results. The limitations are mainly related to low family involvement and high parents and teacher motivation to engage in instruction, which might account for the degree of positive effect of the program in encouraging the review process or stimulating motivational elements. Thus, the effectiveness of the intervention program to enhance improvements in students' written products in the third cycle of Primary education, its stability and application to other forms of writing, as well as to encourage the activation of the mental processes responsible for efficient text processing, especially in regard to planning, are all confirmed. Similarly, we conclude that the family context, and parents in particular, perfectly complement the teaching of writing. Their potential to stimulate their children's writing competence through

Preventing Children's Writing Difficulties Through Specific Intervention in the Home 125

Cusumano, K. (2008). Every mark on the page: education family and community members

Cutler, L., & Graham, S. (2008). Primary grade writing instruction: a national survey. *Journal*

De Caso, A. M., & García, J. N. (2006a). Relación entre la motivación y la escritura

De Caso, A. M., & García, J. N. (2006b). What is missing from current writing intervention

Dunsmuir, S., & Blatchford, P. (2004). Predictors of writing competence in 4- to 7- year-old

Elish-Piper, L. (2010). Parent involvement in reading. *Illionois Reading Council Journal, 38*(4),

Fabregat, S. (2009). Competencia lingüística y expresión escrita en ESO: cinco textos de

Feiler, A. (2003). A home visiting project for reception children predicted to experience literacy difficulties. *British Journal of Special Education, 30*(3), 156-162. Fernández, M. P. (Coord. 2007). *La competencia en comunicación lingüística en las áreas del*

Fidalgo, R., García, J. N., Torrance, M., & Robledo, P. (2009). Cómo enseñar composición

Frijters, J., Barron, R., & Brunello, M. (2000). Direct and mediated influences of home literacy

García, J. N. & de Caso, A. M. (2006). Comparison of the effects on writing attitudes and

disabilities. *International Journal of Educational Research, 43* (4-5), 272-289. García, J. N., & Fidalgo, R. (2003). Cambios metacognitivos de los procesos psicológicos de la

*of General and Applied Psychology], 56(2),* 239-253.

[Relationship between motivation and writing]. *Revista Latinoamericana de Psicología*

programmes? The need for writing motivation programmes. *Estudios de Psicología*

Daniel Cassany [Language proficiency and writing in ESO (Compulsory Secondary

*currículo [Linguistic communication competence in the different areas of the curriculum].* Madrid: Ministerio de Educación y Ciencia, Instituto Superior de Formación del Profesorado [Madrid: Ministry of Education and Science, Institute of Teacher

escrita en el aula: Un modelo de instrucción cognitivo-estratégico y auto-regulado [How to teach writing composition in the classroom: A cognitive model of instruction and self-regulation]. *Aula Abierta [Open Education], 37(1),* 105-116. Fidalgo, R., Torrance, M., & García, J. N. (2008). The long term effects of strategy-focussed

writing instruction for grade six students. *Contemporary Educational Psychology,*

and literacy interest on prereaders´oral vocabulary and early written language skill. *Journal of Educational Phychology, 92*(3), 466-477. doi:10.1037//0022-06<IP_ADDRESS>6 Galbraith, D., & Torrance, M. (1999). Conceptual processes in writing: From problem solving

to text production. In M. Torrance and D. Galbraith (Eds.), *Knowing what to write. Conceptual processes in text production* (pp. 1-12). Amsterdam: Amsterdam University

writing self-efficacy of three different training programs in students with learning

escritura en alumnos de 3º de EP a 3º de ESO [Metacognitive changes in the psychological processes involved in writing in students from 3rd year of Primary Education to 3rd year of Secondary]. *Revista de Psicología General y Aplicada [Journal*

about young children´s writing. *Language Arts, 86*(1), 9-17.

children. *British Journal of Educational Psychology*, 74, 461-483.

Education): five texts by Daniel Cassany]. *Caleidoscopio,* 2, 57-66.

*[Latin American Journal of Psychology], 38*(3), 477-492.

*of Educational Psychology,* 100(4), 907-919.

*[Psychology Studies], 27*(2), 221-242.

53-56.

Training].

*33*(4), 672-693.

Press.

help with homework was confirmed, while we found that for this to be truly effective it is necessary to provide prior systematic training. In this case we chose to create a parent training program, which has proven effective. Therefore, based on our research findings and considering that writing is a complex learning process requiring high doses of motivation and that all environmental stimulation appropriate to the characteristics of child favors its assimilation, we confirm the need for two elements. Firstly, to continue developing teaching schemes focused on this competence based on psychological and communicative approaches. Secondly, to increase the cooperation between school and family, uniting their efforts to improve educational conditions and to enable the students' optimal development, which will enable them to successfully adapt to the growing social demands placed on them (Torío, 2004).

#### **5. Acknowledgments**

During this research study, we received competitive funds from the Spanish Ministry of Education, Science and Innovation (MICINN) (EDU2010-19250 / EDUC) for 2010-2013, and Excellence Research Group funds from the Junta de Castilla y León (GR259), with FEDER funds from the European Union for 2009-2010-2011 (BOCyL 27 on April 2009). Both were awarded to the Director/Main Researcher (J. N. García). We are very grateful to Victoria Rosa Sturley for her help with the English version.

*Correspondence* should be addressed to Departamento de Psicología, Sociología y Filosofía. Área Psicología Evolutiva y de la Educación. Campus de Vegazana s/n, 24071 – León, Spain. Phone: +34-987291041 (university); +34-987222118 (home); +34-652817871 (cell); Fax: +34-987291035 (university). E-mail<EMAIL_ADDRESS>
#### **6. References**

help with homework was confirmed, while we found that for this to be truly effective it is necessary to provide prior systematic training. In this case we chose to create a parent training program, which has proven effective. Therefore, based on our research findings and considering that writing is a complex learning process requiring high doses of motivation and that all environmental stimulation appropriate to the characteristics of child favors its assimilation, we confirm the need for two elements. Firstly, to continue developing teaching schemes focused on this competence based on psychological and communicative approaches. Secondly, to increase the cooperation between school and family, uniting their efforts to improve educational conditions and to enable the students' optimal development, which will enable them to successfully adapt to the growing social demands placed on them

During this research study, we received competitive funds from the Spanish Ministry of Education, Science and Innovation (MICINN) (EDU2010-19250 / EDUC) for 2010-2013, and Excellence Research Group funds from the Junta de Castilla y León (GR259), with FEDER funds from the European Union for 2009-2010-2011 (BOCyL 27 on April 2009). Both were awarded to the Director/Main Researcher (J. N. García). We are very grateful to Victoria

*Correspondence* should be addressed to Departamento de Psicología, Sociología y Filosofía. Área Psicología Evolutiva y de la Educación. Campus de Vegazana s/n, 24071 – León, Spain. Phone: +34-987291041 (university); +34-987222118 (home); +34-652817871 (cell); Fax:

Alamargot, D., & Chanquoy, L. (2001). *Through the Models of Writing.* Dordrecht: Kluwer

Arias, O., & García, J. N. (2007). Eficacia de la instrucción en los aspectos mecánicos y/o

Axford, B. (2007). Parents and their children working together: a scaffolding literacy case

Bodovski, K., & Youn, M. (2010). Love, discipline, and elementary school achievement: the

Burnett, K., & Farkas, G. (2009). Poverty and family structure effects on children´s

Cayo, C. (2008). *Los menores con discapacidad en España [Children with disabilities in Spain].*

Clemente, M., Ramínez, E., & Sánchez, C. (2010). Resumen de enfoques teóricos y prácticas

semánticos de la revisión textual [Effectiveness of instruction in the mechanic and/or semantic aspects of text revision]. *Análisis y Modificación de Conducta*

mathematics achievement: estimates from random and fixed effects models. *The*

docentes en la enseñanza inicial de la lengua escrita [Summary of theoretical approaches and teaching practices in the initial teaching of written language].

(Torío, 2004).

**6. References**

Academia Press.

Madrid: Ediciones Cinca.

**5. Acknowledgments**

Rosa Sturley for her help with the English version.

+34-987291035 (university). E-mail<EMAIL_ADDRESS>
*[Analysis and Behavior Modification], 33(147)*, 5-30.

study. *Australian Journal of Language and Literacy, 30*(1), 21-39.

role of family emotinal climate. *Social Science Research, 39*, 585

*Social Science Journal, 46*, 297-318. doi:10.1016/j.soscij.2008.12.009

*Cultura y Educación [Culture and Education], 22*(3),313-328.

Preventing Children's Writing Difficulties Through Specific Intervention in the Home 127

McElvany, N., & Arle, C. (2007). The Berlin-Parent child program: desing and effects*.*

Mensha, F., & Kiernan, E. (2010). Gender differences in educational attainment: influences of

Ministerio de Educación y Ciencia (MEC, 2006). Ley orgánica 2/2006 de 3 de mayo, de

Montealegre, S., & Forero, L. (2006). Desarrollo de la lectoescritura: asdquisición y dominio

Muñoz, C. (2008). Desarrollar competencias. Un desafío de los docentes de primaria

Neuman, M., Hood, M., & Neuman, D. (2009). The scaffolding of emergent literacy skills in

Novoa, A. (2010). La construcción de un espacio educativo europeo: gobernando a través de

Olive, T., Kellogg, R. T., & Piolat, A. (2002). The triple task technique for studying the

Pardo, E. (2009). ¿Qué pueden aportar las familias a la escuela? [How can families help

Pérez, P., & Zayas, F. (2007). *Competencia en comunicación lingüística [Liguistic Communication*

Persampieri, M., Gortmaker, V., Daly, E. J., Sheridan, S. M., & McCurdy, M. (2006).

Powell, D., Son, S., File, N., & San Juan, R. (2010). Parent-school relationships and children´s

Rasinki, T., & Padak, N. (2009). Write son. *The Reading Teacher, 62*(7), 618-620. doi:

*for studying writing* (pp. 31-61). Dordrecht: Kluwer Academic Publishers. Pajares, F., Valiente, G., & Cheong, Y. F. (2006). Writing self-efficacy and its relation to

*Educativa [Classroom of Educative Innovation], 15*(170), 13-15.

the family environment. *British Educational Research Journal, 36*(2), 239-260.

[Literacy development: acquisition and proficiency]. *Revista Electrónica Interuniversitaria de Formación del Profesorado [Inter-University Electronic Journal of*

[Developing competences. A challenge for primary teachers]. *Aula de Innovación*

the home environment: a case study. *Early Childhood Educational Journal*, 36, 313–

los datos y la comparación [Building a European education area: the governing through data comparison]. *Revista Española de Educación Comparada [Spanish Journal*

process of writing. In T. Olive & C. M. Levy (Eds.) *Contemporary tools and techniques*

gender, writing motivation, and writing competence: A developmental Perspective. In G. Rijlaarsdam, P. Boscolo, & S. Hidi (Eds.), *Studies in writing. Volume 23, Writing*

schools?] *Actas do X Congresso Internacional Galego-Português de Psicopedagogia [Conference Proceedings of the 10th International Gallician-Portuguese Psychoeducation Congress]* (pp. 2153-2160). Braga: Centro de Investigação em Educação (CIEd),

Promoting parent use of empirically supported reading interventions: Two experimental investigations of child outcomes. *Behavioral Interventions,* 21, 31–57. Policastro, M., Mazeski, D. K., & McTague, B. (2010). Parent Involvement in Reading. *Illinois*

academic and social outcomes in public school pre-kindergarten. *Journal of School*

*Psychologie in Erziehung un Uterricht, 4*, 312-330

Educación (LOE) [Education Organic Law].

doi:10.1080/01411920902802198.

*Teacher Education], 9*(1), 25-40

319. doi 10.1007/s10643-008-0291-y

*of Comparative Education], 16,* 23-41.

Universidade Minho.

*and motivation* (pp. 145-162). Oxford: Elsevier.

*Competence]. Madrid:* Alianza Editorial.

*Reading Council Journal*, 39(1), 60-64.

*Psychology, 48*(4), 269-292.

10.1598/RT.62.7.9

García, J. N. & Fidalgo, R. (2006). Effects of two types of self-regulatory instruction programs

García, J. N., Fidalgo, R., & Robledo, P. (2010). The influence of two self-regulatory

García, J. N., Marbán, J. M. & de Caso, A. M. (2001). Evaluación colectiva de los procesos de

Gilbert, J., & Graham, S. (2010). Teaching Writing to Elementary Students in Grades 4-6: A

Graham, S. (1999). The role of Text Production Skills in Writing Development. *Learning*

Hegarty, S. (2008). Investigación sobre educación especial en Europa [Research on special

Hood, M., Conlon, E., & Andrews, G. (2008). Preschool home literacy practices and

Jones, D., & Christensen, C. (1999). The relationship between automatic in handwriting and

Kellogg, R. (2008). Training writing skills: A cognitive developmental perspective. *Journal of*

Lacasa, P., Gómez, M., Reina, A. & Cosano, C. P. (1999). Los deberes escolares en una clase

Lecuona, P., Rodríguez, J., & Sánchez, C. (2003). Evaluación de modelos de composición

Primary education]. *Revista de Educación [Journal of Education], 332,* 301-326. Llach, S., & Alsina, Á. (2009). La adquisición de competencias básicas en Educación

Lozano, E., Galián, D., & Cabello, F. (2009). Intervención familiar en niños con trastornos del

education in Europe]. *Revista Electrónica Iberoamericana sobre Calidad Eficacia y Cambio en Educación [Ibero-American Electronic Journal on Quality, Efficiency and*

children´s literacy development: a longitudinal analysis. *Journal of Educational*

students, ability to generate written text. *Journal of Educational Psychology, 91*, 44-49.

de lengua [Homework in a language class]. *Cultura y Educación [Culture and*

escrita en Educación Primaria [Evaluation of models of written composition in

Primaria: una aproximación desde la Didáctica de la lengua y de las matemáticas [The adquisition of basic competences in Primary Education: An interdisciplinary approach from the teaching of language and mathematics]. *Revista Electrónica Interuniversitaria de Formación del Profesorado [Inter-University Electronic Journal of*

lenguaje: una revisión [Family intervention on children with language disorders: a review]. *Electronic Journal of Research in Educational Psychology, 7*(3), 1419-1448. McArthur, C., Graham, S., & Fitzgerald, J. (2006, Eds.). *Handbook of writing research*. New

efficacy. *Learning Disability Quarterly, 29*(3), 181-211.

595-611). Almería: Education and Psychology

*psychopedagogical intervention*]. Barcelona: Ariel.

*Disability Quarterly, 22*(2), 75-77.

*Change in Education], 6*(2), 191-199.

*Writing Research, 1(1),* 1-26.

*Teacher Education], 12* (3), 71-85.

York: The Guilford Press.

*Education],* 13, 71-88.

National Survey. *Elementary School Journal*, *110*(4), 494-518.

*Phychology, 100*(2), 252-271. Doi:10.1037//0022-06<IP_ADDRESS>

on students with learning disabilities in writing products, processes, and self

instructional programs in the development of writing competence in students with and without learning disabilities. In J. de la Fuente, & A. E. Mourad (Eds.) *International handbook on Applying Self-Regulated Learning in Different Settings (pp*.

planificación y factores psicológicos en la escritura [Collective assessment of writing planning processes and psychological factors]. En J. N. García, *Dificultades de aprendizaje e intervención psicopedagógica* (pp. 151-155) [*Learning disabilities and*

**8**

*University of León*

*Spain*

**The Family Environment of**

**Students with Learning Disabilities and ADHD**

In recent decades there has been a proliferation of studies on the empirical aspect of the family influence on school development of children, and trends have emerged which analyze the effects of household structural and dynamic variables on student learning (Xia, 2010). Results show that family socioeconomic level (Dearing, McCartney & Taylor, 2009; Gil, 2011, Liu & Lu, 2008; Park, 2008), its typology characteristics (Burnett & Farkas, 2008; Gennetian, 2005 ), a suitable home environment (Barkauskiene, 2009; Bodovski & Youn, 2010; Campbell & Berne, 2007; Ghazarian & Buehler, 2010; Khan, Haynes, Armstrong, & Ronher, 2010) and parents' positive outlook on education and their active involvement in it (Flouri & Buchanan, 2004; Phillipson, 2010; Powell, Son, File, & San Juan, 2010; Regner, Loose, & Dumas, 2009; Sirvani, 2007; Mo & Singh, 2008) are factors affecting the academic development of the vast majority of children. This influence is even more relevant for pupils with complex problems that can affect their ability to learn, such as specific learning disabilities (hereafter LD) or attention deficit disorder with/without hyperactivity (ADHD). Such pupils usually have special educational needs which require specific attention in all microenvironments in which education takes place, including the family (Snowling, Muter,

LD is a concept that encompasses a heterogeneous group of disorders that manifest in significant difficulties in understanding, speaking, reading, writing, reasoning, and mathematical ability, presumably of biological origin and related to the functioning of the central nervous system (Kavale & Forness, 2000; Lerner & Kline, 2006). As for ADHD, it is a neuropsychological disorder that is characterized by a persistent pattern of inattention and/or hyperactivity-impulsivity that affects the social, academic and/or work life areas of the sufferer's life (Frazier, Youngstron , Glutimg, Watkins, & Marley, 2007; Jakobson & Kikas, 2007). Therefore, it is maintained that ADHD and LD are disorders of biologicalgenetic origin which are intrinsic to the individual. However, there has now been a shift in focus towards environmental variables, including the family, which are it is claimed can enhance or minimize the negative effects of these difficulties and, therefore, must be thoroughly examined and taken into consideration (Pheula, Rohde, & Schmitz, 2011;

The research available on learning and environmental conditions confirms the importance of adequate family functioning, as well as the existence of a satisfactory home environment to

**1. Introduction**

& Carroll, 2007; Shur-Fen , 2007).

Snowling, et al. 2007; Shur-Fen, 2007).

Patricia Robledo-Ramón and Jesús-Nicasio García-Sánchez


4. Conclusions

In this study, an analytical protocol involving the combination of HS-SPME coupled to GC–MS and ASE coupled to HPLC-HRMS (Orbitrap®) was applied for the in-depth profiling and fingerprinting of cannabinoids and terpenes in an authorised medical grade variety of Cannabis sativa L. (Bediol®). HS-SPME was shown to be an excellent technique to investigate both the cannabis inflorescence and derived macerated oil volatile composition. In particular, HS-SPME extraction provides an accurate profile concerning plausible terpenes fingerprint of different cannabis chemotypes, as presented in this study.

LC-HRMS-Orbitrap, used to investigate cannabinoids extracted from inflorescences and macerated oils, showed high-throughput performances, as it can be used both for quantification of target analytes and to investigate untargeted fraction to obtain a very complex prolife as an expression of plant phytocomplex at the same time.

These approaches are nowadays essential and pivotal in order to understand the composition of Cannabis sativa chemotypes currently used for their role in therapeutic management, as they are able to provide comprehensive information essential to then correlate the phytochemical characteristics of cannabis and the clinical results obtained when managed and administered to patients as well.


**2. Materials and Methods**

An Fe-20%Mn-8%Al-5%Ni-0.8%C (mass%) was used in the present study, which has a chemical composition similar to that used in previous studies by Kim et al. and Yang et al. [16,17]. An as-received ingot having dimension of 100 mm (length) × 50 mm (width) × 20 mm (thickness) was cut into small blocks with 10 mm in thickness, and then solution-treated at 1280 ◦C for 1 h in argon atmosphere followed by water quench. After that, the plate was cold-rolled from 10 to 1.2 mm by multiple rolling passes, which corresponded to an 88% rolling reduction in thickness. The cold-rolled specimen was annealed at 850 ◦C for 120 min in a salt bath and then quenched into water. Tensile test specimens having 7.5 mm in gauge length, 2.5 mm in gauge width, and 1.2 mm thick were cut from the annealed sheet, with the tensile axis parallel to the rolling direction (RD) of the sheets. The surface perpendicular to the normal direction (ND) of the sheet specimen was decorated by white and black paint, and a CCD camera was used to record the images of the surface during the tensile test. Those images were analyzed afterwards by a digital image correlation (DIC) software (VIC2D) to obtain the precise tensile elongation and strain localization behaviors during the tensile deformation. The details about the DIC system used in the present experiments were described in Reference [18]. Tensile tests were carried out at room temperature at an initial strain rate of 8.3 × 10−4 s−1. Microstructures of the specimen were observed from the transverse direction (TD) of the specimens by a scanning electron microscope (SEM) equipped with an electron backscatter diffraction (EBSD) system (JSM-7100F, JOEL Ltd., Tokyo, Japan), using an acceleration voltage of 15 kV and a scan step size of 50 nm.

To investigate the individual deformation behavior of constituent phases in the material during tension, another tensile test with in situ X-ray diffraction (XRD) was conducted at the beam line BL46XU of SPring-8 in Harima, Japan. The experimental setup of the in situ XRD measurement is schematically illustrated in Figure 1. The energy of the X-ray was 30 keV, corresponding to a wavelength of 0.0413 nm. The incident X-ray beam having a size of 0.5 × 0.3 mm was irradiated perpendicular to the tensile test specimen during tensile deformation, and the diffracted X-ray in the diffraction angle (2θ) from 9.8◦ to 40.3◦ was detected by a one-dimensional detector composed of six MYTHEN detectors (DECTRIS Ltd., Baden-Daettwil, Switzerland) arranged in a line. The exposure time for each X-ray diffraction profile was set to 1 s. The tensile test specimen described earlier was further polished to 0.5 mm in thickness to ensure the penetration of the X-ray beam, and a strain rate of 8.3 × 10−4 s−1 was applied for the tensile test. After the tensile test, the diffraction peaks in a profile were fitted using the pseudo-Voigt function. For more details of the in situ XRD measurements in BL46XU, one can refer to References [19–21].

**Figure 1.** Schematic illustration of the in situ X-ray diffraction (XRD) measurement system in SPring-8.


**2. Hunza River basin**

*Glaciers and the Polar Environment*

due to rugged mountains and the limited data availability because there is a highly different precipitation rate due to the settings and steep topography. Similarly, there are extremely different ablation rates due to aspect and variable debris cover on the glaciers. However, an extensive field study was conducted by the Snow and Ice Hydrology Project (SIHP) of Water and Power Development Authority (WAPDA) with the collaboration of Canadian University during the 1980s. It was reported that the maximum precipitation occurs at the elevation of 4500–5100 m.a.s.l. Moreover, Hewitt [3] reported that about 80% of flows in the Upper Indus River derives from the glaciered region above 3500 m.a.s.l. Recently, researchers have tried to assess the spatial distribution of precipitation by inversely inference of precipitation for glacier mass balance [4] snow cover variation [1, 5] using remote sensing data, Geographical Information System (GIS) techniques, and runoff modeling approaches. Adnan et al. [5] reported that the expansion in snow cover in the Hunza River could be attributed to the surge activities in the basin. Many researchers [6–10] have reported the surge events in the region. Studies on glaciers also indicate the slightly reduced mass balance in the region. However, most of the glaciers have gained the mass in the nourishment zone and loss in the ablation zone. These findings suggest the increase in the slopes of the glacier that could cause increased glacier velocities and the probable advance of glaciers in the future. However, in this chapter, we have presented the existence of glaciers and glacial lakes in the Hunza basin through which the CPEC route passes and is a heavily glaciered region. Many GLOF events and surges have been reported in the basin, especially, along the CPEC route. Moreover, glaciers are sensitive indicators of global climate change because they remain sensitive to global temperature conditions as specified by their continuous retreat which has been witnessed in many parts of the world including the Hindu-Kush Karakoram Himalaya (HKH) region especially CPEC route [9, 11]. After the industrial revolution, the rapid glaciers melting and its associated retreating trend left a major concern to the scientists and managers in the region. The substantial glaciers melting not only decrease the rivers discharge in the long run but also bring the high sediment load which causes flash floods in downstream areas and has a direct posture on the life of hydropower projects and socio-economic consequences

for the local people and those living in downstream areas.

well for long-term development and planning in this region [12, 13].

Terminal moraines and glacial lakes have been exposed in these high mountains as a result of surging, substantial melting, and retreating of glaciers. GLOFs have become a matter of concern for social and economic stability in the river valleys because of the rapid addition of meltwater in those glacial lakes adjacent to receding valley glaciers and may lead to sudden breaching of the unstable debris dam. Thus, it is very important to understand the state and fate of these glaciers and lakes as

During the last half-century, a large number of glacial lakes development have been witnessed in the CPEC region, and at the same time, several GLOFs have been reported, especially, in the eastern part of the CPEC region. Probably, remote glacial lakes are under risk and they may impact the downstream inhabitant as a result of GLOFs. These GLOFs may have devastating effects on the population as

The understanding that GLOFs can significantly surpass design floods of Hydropower Plant (HPP) under the threat of destruction or complete non-functionality is based on few case studies [17–19] but a clear picture of regional GLOF exposure remains vague. The previous glacial lake inventories to identify future GLOF sources have neglected their impacts on downstream areas [20]. However,

**1.1 Glacial Lake Outburst Floods (GLOFs)**

well as property and infrastructure [14–16].

**106**

CPEC is in the interest of both the countries China and Pakistan; it will develop connectivity between west China and south China; and it is an integrated part of the "One Belt One Road" initiative policy. The establishments of China and Pakistan have agreed to complete the CPEC route from Kashgar (China) to Gwadar (Pakistan) by the end of 2030. The Chinese government is providing necessary support in terms of finance and logistics to build the infrastructure along the CPEC route. The CPEC is not only important for both the countries but also will prove beneficial for the surrounding countries. This project will strengthen the economic growth of Pakistan and it is the right initiative for both the countries. This corridor is considered a sign of peace, prosperity, and development. Even though this economic corridor is challenging but it will open new horizons of development in the future for both the countries. In the past, the lack of the right decision and insufficient opportunities have always remained a hurdle in the way of Pakistani peoples but CPEC will have transformational impacts on the state and the prosperity Pakistani nationals. The Chinese president Xi's visit in April 2015 and the announcement of \$46 billion-plus for various CPEC projects drew the world's attention to this region because new development and growth of the economy will benefit both of the countries under the umbrella of this economic corridor. In the meeting called by the Prime Minister of Pakistan, all political parties have supported the CPEC and project and warmly welcomed the Chinese investment. This project will bring a revolution in the lives of over 3 billion people in this region. It will improve the strategic and economic location of Pakistan through trade and investment and exploration of mineral resources. Alternatively, according to China's perspective, this is a "flagship project" because it provides the shortest route to the Middle East, Africa, and Europe, which will boost up its economy. This corridor is passing through the Northern part of Pakistan.

The northern part of Pakistan is mostly consisting of a mountainous region, which is rich in glaciers and glacial lakes. The source of water in the river is glacier melting and rainfall. The population living downstream is under high risk due to the melting of glaciers and GLOFs [26–28]. International Center for Integrated Mountain Development (ICIMOD's) published an inventory in 2005, which comprised of 2420 glacial lakes in 10 major river basins of Hindukush Karakoram Himalayan Region of Pakistan [29]. The different river basins have glacial lakes such as Gilgit (614), Indus (574), Swat (255) Shingo (238), and Hunza (110). The Gilgit River basin comprised of 614 glacial lakes and 380 lakes out of 614 were identified

**Figure 1.** *Study area of China Pakistan economic corridor.*

as major lakes, which contribute 62% of the total lakes. These major lakes form 93% of the lake area of the basin. New glacial lakes also formed due to glaciers thinning and retreating of this region. These lakes are categorized according to risk, 52 glacial lakes identified in this region. Passu lake has experienced historical GLOF events, which lie in the Hunza River basin [6]. The location of Passu lake is 38 km away and directed to the East-West of Passu glacier in the HKH region (**Figure 1**). The climate of Hunza is moderate, which have minimum and maximum temperature of 16 and 35.9°C, respectively. The annual average rainfall in this region is 136.2 mm with a minimum (2.1 mm) and maximum (283.2 mm) in November and April, respectively [30].


Hence, the skin layer (top layer) is formed by gelation and the porous sublayer (bottom layer) is the result of liquid–liquid phase separation by nucleation and growth. On the one hand, the factor which is determining the type of phase inversion at any point in the cast sheet is the local polymer concentration at the moment of precipitation. On the other hand, in the first split second after immersion in the coagulation bath, there is a fast depletion of solvent from the casted film and a relatively small penetration of nonsolvent. Thus, this means that the concentration of polymer in the film/bath interface increases, which crosses the gel boundary (transition H to G in Fig. 10). The thin and dense gel-layer which is induced by this way will work as a resistance to solvent outdiffusion and at positions beneath the skin layer (top layer). At lower polymer and higher nonsolvent concentrations, demixing process will take place. Thus, the type of demixing process in that case will be liquid–liquid phase separation (transition H to L in Fig. 10). At the end of the process, the demixing gap is entered at the polymer-rich side of the critical point (CP), so the nuclei consist of the polymer-poor phase, and a porous sublayer structure is formed, the pores of which are filled with the dilute solvent/nonsolvent

**Figure 10.** Mechanism of formation of asymmetric membrane, ternary phase diagram containing P, polymer; S, solvent; NS, nonsolvent; CP, critical point; G, gelation (gel region); L, liquid–liquid phase separation( two phase region); H, homogeneous

**separation**

L:**liquid-liquid phase**

Conversely to the case of precipitation from the vapor phase, the casted polymer solution, in this case, is in contact directly with a nonsolvent vapor phase. In addition, the nonsolvent vapor phase is saturated with the solvent used. On the one hand, in this process, there is no solvent outflow from polymer casted solution but only a nonsolvent inflow to polymer casted solution. On the other hand, the only possible demixing mechanism is liquid–liquid phase separation to form symmetric microporous membrane without a dense

> **P** 1

**S** 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0

**Figure 11.** Formation symmetric microporous membrane of a polymer film with initial composition D when brought in

In this section, the influence of some parameters on membrane morphology will be described. It is known that there are two different types of membranes can be obtained, asymmetric membranes (i.e., reverse osmosis, nanofiltration, and ultrafiltration) and symmetrical mem‐ branes (i.e., dense membrane), depending on the type of formation mechanism, i.e. instanta‐

It is obvious that the kinetics of phase separation during the immersion of a polymer/ solvent mixture in a nonsolvent bath plays a major role in the control of membrane morphology [44]. The accelerated rate of phase separation due to the addition of nonsol‐ vent additive may be restricted in the rearrangement of polymer aggregates, resulting in the formation of membrane with small macrovoids. Surface properties of membranes can be controlled depending on the casting conditions, polymer solution, and coagulation bath

0

**NS** 1

0.9

0.8

0.7

0.6

 **E** (**liquid–liquid phase separation)**

0.5

0.4

0.3

0.2

0.1

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

**D**

0.1

0

reported that the top layer is formed by gelation while liquid–liquid phase separation forms the sublayer of the membrane.

G : **Gelation**

CP

phase.

solution (one phase region) [41,42].

**<IP_ADDRESS> Mechanism of formation symmetric microporous membrane**

a nonsolvent vapor phase saturated with solvent [39–41**]**.

top layer. The change of composition in the casted film is illustrated in Fig. 11 (transition D to E).

58 Desalination Updates

**H :**

 **Homogeneous**

 **solution**

In order to obtain an optimal membrane structure, an additive or cosolvent is frequently used. The addition of a fourth component to a casting solution or a nonsolvent coagulant bath is an important method used in membrane modification. Many researchers studied the effects of additive materials in a coagulation bath with other factors, which can influence membrane formation.

The choice of solvent/nonsolvent is one of the main variables in the wet-phase inversion process which is influenced by the membrane formation. Generally, the membrane morphol‐ ogy can be characterized by scanning electron microscopy (SEM). In the case of delayed liquid– liquid demixing, a sponge-like structure can be formed, and in the case of instantaneous demixing, finger-like structure can be formed [1, 2, 32]. Generally, in the case of higher affinity between the solvent and coagulant, however, instantaneous demixing process takes place, but for a lower affinity between the solvent and coagulant, the delayed demixing process takes place [2, 32].

By addition of cosolvent to polymer/solvent solution with low-affinity coagulant, the polymer solution system will be shifted from instantaneous demixing to delayed demixing process. This is due to the lower affinity of cosolvent with coagulant than solvent. In the case of delayed demixing, a dense skin layer is formed; this inhibits the inflow of nonsolvent (water) into the polymer solution. Further, in the case of delayed demixing, the number and the size of nuclei of polymer-poor phase become smaller. Therefore, macrovoids significantly disappear. By increasing the amount of cosolvent, the numbers of macrovoids become smaller, and the top layer shows a very packed and dense shape. When the ratio of cosolvent to solvent is increased, almost all the macrovoids disappear and the spongy structure starts formation. Without the addition of cosolvent, large fingers are formed because of instantaneous demixing and the upper part of the membrane is porous.

Water-miscible solvent (wms) and water-immiscible solvents (wis) can be used in the casting solution in order to prepare asymmetric membranes. Because (wis) is immiscible with water, it is left in the membrane after coagulation and can further modify the membrane structure through its solvency power.

Kim et al. [45] developed the formation of integrally skinned asymmetric polyetherimide nanofiltration membranes by phase inversion process and showed that the polymer solution system is shifted from instantaneous demixing to delayed-demixing process. This is due to the lower affinity of 1, 4-dioxane (cosolvent) with water (nonsolvent) than DMF (solvent). By increasing the amount of 1, 4-dioxane, the number of macrovoids became smaller and the top layer shows a very packed and dense shape. Without the addition of 1, 4-dioxane, large fingers were formed because of instantaneous demixing and the upper part of the membrane was porous.

Shieh et al. [46] studied the preparation of polyetherimide membranes from water-miscible/ immiscible mixture solvents and reported that the PEI/NMP/H2O system exhibits an instan‐ taneous liquid−liquid phase separation property, but the phase separation rate reduces with the addition of methlyene chloride (MC) into the casting solution. The decrease in the phase separation rate may be mainly due to the difference in solubility parameters; water is 47.9 (MPa)1/2, while MC is 19.8 (MPa)1/2. The elongated macrovoids diminish gradually as the MC content increases, and no macrovoids are formed when the MC content is 30 wt% in the casting solution.

#### *4.9.2. Effect of Immersion Bath Temperature (IBT)*

Immersion bath temperature is an important parameter in membrane morphology and performance. It was found that with asymmetric membranes, the porosity increases with the increase of the immersion bath temperature [47]. Raising the temperature increases mutual diffusivities between the nonsolvent (as water) and the solvent (as DMF) in the casting solution during demixing process. In addition, in the former case, the increase of coagulation bath temperature [48] rises the speed of nucleus growth of polymer-poor phase, that is, increases the formation of porous structure in the membrane. Conversely, in the latter case, at the reduction of the temperature, the speed of nucleus growth is limited and the formation of a large number of small nucleuses is increased, so a great number of pores/voids are formed in the bottom layer of the asymmetric membranes. Therefore, the formation of macrovoids is prevented and denser membrane structures are obtained.

Kim et al. [42] prepared skinned asymmetric polyetherimide nanofiltration membranes by phase inversion process and reported that light transmittance of experiment showed an increase with coagulation bath temperature; demixing of the casting solution was gradually shifted from delayed demixing to instantaneous demixing. When the casting solution [PEI/DMF/1, 4-dioxane (16/28/56)] was coagulated at the temperature of 25o C, porous spongylike structure was formed. However, lower coagulation temperature (<10 o C) makes the membrane structure dense spongy.

#### *4.9.3. Effect of polymer concentration*

Generally, increasing polymer concentrations in the casting solution slows down the demixing process, leads to a much higher polymer concentration at the interface [49], and increases the thickness of the top layer and decreases the porosity of the membrane. The macrovoids formation will be diminished, and the pore size will decrease. Conversely, the reduction of the polymer concentration in the casting solution indeed leads to a more open and porous structure with large pores. Such a phenomenon has been reported in cellulose acetate/dimethyl sulfox‐ ide/water [50] and Nomex/*N*, *N*-dimethylacetamide/water systems [51]. Furthermore, me‐ chanical properties of the membranes prepared with a low polymer concentration are lower than for a membrane prepared with a high polymer concentration.

### **5. Process block flow diagram for membrane desalination**

Fortunately, there are different types of membranes which can be used for membrane desali‐ nation by using different technologies such as (RO), (MD), and (FO). In this section, major emphasis is placed on the preparation of membrane distillation (MD) and reverse osmosis (RO) via phase inversion process.

#### **5.1. Membrane Distillation (MD)** reported in cellulose acetate/dimethyl sulfoxide/water [50] and Nomex/*N*,*N*-dimethylacetamide/water systems [51]. Furthermore,

these materials are presented in Figs. 12–18.

were formed because of instantaneous demixing and the upper part of the membrane was

Shieh et al. [46] studied the preparation of polyetherimide membranes from water-miscible/ immiscible mixture solvents and reported that the PEI/NMP/H2O system exhibits an instan‐ taneous liquid−liquid phase separation property, but the phase separation rate reduces with the addition of methlyene chloride (MC) into the casting solution. The decrease in the phase separation rate may be mainly due to the difference in solubility parameters; water is 47.9 (MPa)1/2, while MC is 19.8 (MPa)1/2. The elongated macrovoids diminish gradually as the MC content increases, and no macrovoids are formed when the MC content is 30 wt% in the casting

Immersion bath temperature is an important parameter in membrane morphology and performance. It was found that with asymmetric membranes, the porosity increases with the increase of the immersion bath temperature [47]. Raising the temperature increases mutual diffusivities between the nonsolvent (as water) and the solvent (as DMF) in the casting solution during demixing process. In addition, in the former case, the increase of coagulation bath temperature [48] rises the speed of nucleus growth of polymer-poor phase, that is, increases the formation of porous structure in the membrane. Conversely, in the latter case, at the reduction of the temperature, the speed of nucleus growth is limited and the formation of a large number of small nucleuses is increased, so a great number of pores/voids are formed in the bottom layer of the asymmetric membranes. Therefore, the formation of macrovoids is

Kim et al. [42] prepared skinned asymmetric polyetherimide nanofiltration membranes by phase inversion process and reported that light transmittance of experiment showed an increase with coagulation bath temperature; demixing of the casting solution was gradually shifted from delayed demixing to instantaneous demixing. When the casting solution

Generally, increasing polymer concentrations in the casting solution slows down the demixing process, leads to a much higher polymer concentration at the interface [49], and increases the thickness of the top layer and decreases the porosity of the membrane. The macrovoids formation will be diminished, and the pore size will decrease. Conversely, the reduction of the polymer concentration in the casting solution indeed leads to a more open and porous structure with large pores. Such a phenomenon has been reported in cellulose acetate/dimethyl sulfox‐ ide/water [50] and Nomex/*N*, *N*-dimethylacetamide/water systems [51]. Furthermore, me‐ chanical properties of the membranes prepared with a low polymer concentration are lower

C, porous spongy-

C) makes the

[PEI/DMF/1, 4-dioxane (16/28/56)] was coagulated at the temperature of 25o

than for a membrane prepared with a high polymer concentration.

like structure was formed. However, lower coagulation temperature (<10 o

porous.

60 Desalination Updates

solution.

*4.9.2. Effect of Immersion Bath Temperature (IBT)*

prevented and denser membrane structures are obtained.

membrane structure dense spongy.

*4.9.3. Effect of polymer concentration*

Membrane distillation is a thermal, vapor-driven transportation process through microporous and hydrophobic membranes. It is a low-cost membrane separation technology and energysaving process. Membrane distillation (MD) is generally used to remove water from aqueous solutions of inorganic solutes. In this field, desalination is the best-known MD application. The main membrane materials for membrane distillation are typically prepared from polytetra‐ fluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene, polypropylene (PP), and polyether sulphone (PES). The process block flow diagrams for the preparation of MD from these materials are presented in Figs. 12–18. mechanical properties of the membranes prepared with a low polymer concentration are lower than for a membrane prepared with a high polymer concentration. **1.5 Process Block Flow Diagram for Membrane Desalination**  Fortunately, there are different types of membranes which can be used for membrane desalination by using different technologies such as (RO), (MD), and (FO). In this section, major emphasis is placed on the preparation of membrane distillation (MD) and reverse osmosis (RO) via phase inversion process. **1.5.1 Membrane Distillation (MD)**  Membrane distillation is a thermal, vapor-driven transportation process through microporous and hydrophobic membranes. It is a low-cost membrane separation technology and energy-saving process. Membrane distillation (MD) is generally used to remove water from aqueous solutions of inorganic solutes. In this field, desalination is the best-known MD application. The main membrane materials for membrane distillation are typically prepared from polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene, polypropylene (PP), and polyether sulphone (PES). The process block flow diagrams for the preparation of MD from

**Figure 12.** Process flow sheet for the preparation of PVDF membranes for desalination by direct contact membrane distillation [52]. **Figure 12.** Process flow sheet for the preparation of PVDF membranes for desalination by direct contact membrane distillation [52].

Mixing step

Immersion in non solvent (water) at 5 0

Rinsing with running water

Drying procedure

C

Degassing

Solvent (DMF, DMA)

FA: film applicator; S: support

Casting+ Preconcentration

C 30 sec

at 20 0

‐ 7–12 wt % in DMF ‐ 8 wt % in DMA ‐3 wt % LiCl

poly(vinylidene fluoride)

‐ Support: The polyester filament woven fabric

Immersion step

15

‐ 15 wt % in DMF ‐ 8wt % in DMA ‐ LiCl

high polymer concentration.

**1.5 Process Block Flow Diagram for Membrane Desalination**

reverse osmosis (RO) via phase inversion process. **1.5.1 Membrane Distillation (MD)**

these materials are presented in Figs. 12–18.

poly (vinylidene fluoride)

Immersion step

Mixing step

reported in cellulose acetate/dimethyl sulfoxide/water [50] and Nomex/*N*,*N*-dimethylacetamide/water systems [51]. Furthermore, mechanical properties of the membranes prepared with a low polymer concentration are lower than for a membrane prepared with a

Fortunately, there are different types of membranes which can be used for membrane desalination by using different technologies such as (RO), (MD), and (FO). In this section, major emphasis is placed on the preparation of membrane distillation (MD) and

Membrane distillation is a thermal, vapor-driven transportation process through microporous and hydrophobic membranes. It is a low-cost membrane separation technology and energy-saving process. Membrane distillation (MD) is generally used to remove water from aqueous solutions of inorganic solutes. In this field, desalination is the best-known MD application. The main membrane materials for membrane distillation are typically prepared from polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene, polypropylene (PP), and polyether sulphone (PES). The process block flow diagrams for the preparation of MD from

C 30 sec

Degassing

Solvent (DMF, DMA)

FA: film applicator; S: support

C

Casting+ Pre‐concentration

Immersion in non solvent (water) at 5 0

Rinsing with running water

Drying procedure at room temperature 24 hr

**Figure 12.** Process flow sheet for the preparation of PVDF membranes for desalination by direct contact membrane distillation [52].

For liquid film, at 20 0

15 **Figure 13.** Process flow sheet for the preparation of PVDF membranes for desalination by direct contact membrane distillation [53]. **Figure 13.** Process flow sheet for the preparation of PVDF membranes for desalination by direct contact membrane distillation [53].

Mixing step Solvent (DMAC, DMF) Poly(vinylidene fluoride) PVDF **Figure 14.** Process flow sheet for the preparation of PVDF membranes for desalination by direct contact membrane distillation [54].

‐ 10–25 wt% in solvent

16

Casting

**Figure 14.** Process flow sheet for the preparation of PVDF membranes for desalination by direct contact membrane distillation [54].

Degassing

Immersion in water bath (22C)

Washing Drying (45C) overnight

Solvent (DMAC)

Mixing step

**Figure 13.** Process flow sheet for the preparation of PVDF membranes for desalination by direct contact membrane distillation [53].

at 50 0 C

Degassing at 30°C

over 24 h

Casting

‐ 7–12 wt % in DMAC - Pore-forming additives LiClO4·3H2O or/and TMP was used in F2.4 solution

Poly (vinylidene fluoride) PVDF

‐ Support: The polyester filament

woven fabric

+ Preconcentration

Immersion in water at 30°C for 10 min

Soaking in ethanol bath for 2 days

**Figure 14.** Process flow sheet for the preparation of PVDF membranes for desalination by direct contact membrane distillation [54].

**Figure 15.** Process block flow diagram for preparing PVDF membrane [55].

‐ 12–20 wt % in *N*,*N*dimethylacetamide

‐ 10 wt % in nonsolvent butyrolactone (GBL) - Surface-modifying macromolecule (SMM)

Immersion step

(DMAC)

Ultem®1000)

Flat membrane

15

**Figure 13.** Process flow sheet for the preparation of PVDF membranes for desalination by direct contact membrane distillation [53].

Mixing step at 50 0 C

> Degassing at 30°C over 24 h

16

Mixing step

reported in cellulose acetate/dimethyl sulfoxide/water [50] and Nomex/*N*,*N*-dimethylacetamide/water systems [51]. Furthermore, mechanical properties of the membranes prepared with a low polymer concentration are lower than for a membrane prepared with a

Fortunately, there are different types of membranes which can be used for membrane desalination by using different technologies such as (RO), (MD), and (FO). In this section, major emphasis is placed on the preparation of membrane distillation (MD) and

Membrane distillation is a thermal, vapor-driven transportation process through microporous and hydrophobic membranes. It is a low-cost membrane separation technology and energy-saving process. Membrane distillation (MD) is generally used to remove water from aqueous solutions of inorganic solutes. In this field, desalination is the best-known MD application. The main membrane materials for membrane distillation are typically prepared from polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene, polypropylene (PP), and polyether sulphone (PES). The process block flow diagrams for the preparation of MD from

C 30 sec

Degassing

Solvent (DMF, DMA)

FA: film applicator; S: support

Solvent (DMF, DMA)

FA: film applicator; S: support

Solvent (DMAC)

C

Casting+ Pre‐concentration

Immersion in non solvent (water) at 5 0

Rinsing with running water

Drying procedure at room temperature 24 hr

Mixing step

**Figure 12.** Process flow sheet for the preparation of PVDF membranes for desalination by direct contact membrane distillation [52].

Immersion in non solvent (water) at 5 0

Rinsing with running water

Drying procedure

**Figure 13.** Process flow sheet for the preparation of PVDF membranes for desalination by direct contact membrane

Casting

+ Preconcentration

Immersion in water at 30°C for 10 min

Soaking in ethanol bath for 2 days

Drying procedure in air

Mixing step

**Figure 14.** Process flow sheet for the preparation of PVDF membranes for desalination by direct contact membrane

**Figure 14.** Process flow sheet for the preparation of PVDF membranes for desalination by direct contact membrane distillation [54].

Casting

Degassing

Solvent (DMAC, DMF)

Immersion in water bath (22C)

Washing Drying (45C) overnight

C

Degassing

Casting+ Preconcentration

C 30 sec

at 20 0

Flat membrane

For liquid film, at 20 0

‐ 15 wt % in DMF ‐ 8wt % in DMA ‐ LiCl

high polymer concentration.

**1.5 Process Block Flow Diagram for Membrane Desalination**

reverse osmosis (RO) via phase inversion process. **1.5.1 Membrane Distillation (MD)**

these materials are presented in Figs. 12–18.

poly (vinylidene fluoride)

Immersion step

‐ 7–12 wt % in DMF ‐ 8 wt % in DMA ‐3 wt % LiCl

poly(vinylidene fluoride)

62 Desalination Updates

‐ Support: The polyester filament woven fabric

Immersion step

‐ 7–12 wt % in DMAC - Pore-forming additives LiClO4·3H2O or/and TMP was used in F2.4 solution -LiCl

Poly (vinylidene fluoride) PVDF

‐ Support: The polyester filament woven fabric

‐ 10–25 wt% in solvent

Poly(vinylidene fluoride) PVDF

Flat membrane

distillation [54].

distillation [53].

Mixing step Solvent (DMAC) membrane distillation [56].D rms Polymer polyetherimide (PEI, **Figure 16.** Process flow sheet for the preparation of isotactic polypropylene (IPP) membranes for desalination by direct contact membrane distillation [56].

**Figure 16.** Process flow sheet for the preparation of isotactic polypropylene (IPP) membranes for desalination by direct contact

Room temp. 8 h

Degassing

Casting+ Preconcentration

Ethanol solution for 4 h

Immersion in non solvent (water) at 200

Solvent exchange

Drying procedure

C

Mixing step Solvent (DMAC or **Figure 17.** Process flow sheet for the preparation of polyetherimide membranes by direct contact membrane distilla‐ tion [57]. Flat membrane **Figure 17.** Process flow sheet for the preparation of polyetherimide membranes by direct contact membrane distillation [57].

**Figure 17.** Process flow sheet for the preparation of polyetherimide membranes by direct contact membrane distillation [57].

**1.5.2 Process Flow Diagram for RO Membrane Preparation**  The more useable membrane materials for RO are cellulose acetate, polyamide, polyimide, polybenzimidazole, **Figure 18.** Process flow sheet for the preparation of PEI membranes for desalination by direct contact membrane distil‐ lation [58].

of these materials are presented in Figs. (19)–(30).

**Figure 18.** Process flow sheet for the preparation of PEI membranes for desalination by direct contact membrane distillation [58].

polybenzimidazolone, sulfonated-PSF, and chitosan. The process block flow diagrams for the preparation RO membrane from some

#### **5.2. Process flow diagram for RO membrane preparation**

Mixing step Room temp. 8 h

‐ 12–20 wt % in *N*,*N*dimethylacetamide (DMAC)

Polymer polyetherimide (PEI,

**rms**

64 Desalination Updates

tion [57].

lation [58].

Dry membranes

Dry membranes

Ultem®1000)

‐ 10 wt % in nonsolvent butyrolactone (GBL) - Surface-modifying macromolecule (SMM)

Immersion step

‐ 12wt % in *N*,*N*dimethylacetamide (DMAC) or 1‐Methyl‐2‐ pyrrolidinone (NMP) ‐ 10 wt % in nonsolvent butyrolactone (GBL) - Surface-modifying macromolecule (SMM)

‐ 12wt % in *N*,*N*dimethylacetamide (DMAC) or 1‐Methyl‐2‐ pyrrolidinone (NMP) ‐ 10 wt % in nonsolvent butyrolactone (GBL) - Surface-modifying macromolecule (SMM)

Flat membrane

Flat membrane

Flat membrane

**1.5.2 Process Flow Diagram for RO Membrane Preparation**

of these materials are presented in Figs. (19)–(30).

0.5–2 wt%.

0.5–2 wt%.

Polyetherimide (PEI, Ultem®1000)

Polyetherimide (PEI, Ultem®1000)

Casting+ Preconcentration

Ethanol solution for 4 h

Immersion in non solvent (water) at 200

Degassing

Solvent exchange

Drying procedure

**Figure 17.** Process flow sheet for the preparation of polyetherimide membranes by direct contact membrane distillation [57].

**Figure 17.** Process flow sheet for the preparation of polyetherimide membranes by direct contact membrane distillation [57].

**Figure 17.** Process flow sheet for the preparation of polyetherimide membranes by direct contact membrane distilla‐

Mixing step Room temp. 48 h

Mixing step Room temp. 48 h

Degassing

Degassing

Casting+ Preconcentration For liquid film, room temp.

Casting+ Preconcentration For liquid film, room temp.

> Immersion in distilled water at room temp

> Immersion in distilled water at room temp

> > Drying procedure

Drying procedure

**Figure 18.** Process flow sheet for the preparation of PEI membranes for desalination by direct contact membrane distillation [58].

**Figure 18.** Process flow sheet for the preparation of PEI membranes for desalination by direct contact membrane distil‐

The more useable membrane materials for RO are cellulose acetate, polyamide, polyimide, polybenzimidazole, polybenzimidazolone, sulfonated-PSF, and chitosan. The process block flow diagrams for the preparation RO membrane from some

C

Solvent (DMAC)

Solvent (DMAC or

Solvent (DMAC or NMP)

NMP)

The more useable membrane materials for RO are cellulose acetate, polyamide, polyimide, polybenzimidazole, polybenzimidazolone, sulfonated-PSF, and chitosan. The process block flow diagrams for the preparation RO membrane from some of these materials are presented in Figs. (19)–(30).

**Figure 19.** Process block flow diagram for preparing CA membrane [59].

**Figure 20.** Process block flow diagram for preparing CA membrane [60].

**Figure 21.** Process block flow diagram for preparing CA membrane [61].

**Figure 22.** Process block flow diagram for preparing PEI membrane [62].

**Figure 23.** Process block flow diagram for preparing PA-6 membrane [63]. Figure 23. Process Block Flow Diagram for Preparing PA-6 Membrane [63].

**Figure 21.** Process block flow diagram for preparing CA membrane [61].

66 Desalination Updates

**Figure 22.** Process block flow diagram for preparing PEI membrane [62].

3

Figure 24. Process Block Flow Diagram for Preparing Polyamide Membrane [64]. **Figure 24.** Process block flow diagram for preparing polyamide membrane [64].

Figure 24. Process block flow diagram for preparing polyamide membrane [64].

**Figure 25.** Process block flow diagram for preparing PA-6 membrane [65].

Figure 25. Process block flow diagram for preparing PA-6 membrane [65].

**Figure 26.** Process block flow diagram for preparing PA-6 membrane [66].

**Figure 27.** Process block flow diagram for preparing PA- 6/CA membrane [67].

21

Figure 24. Process block flow diagram for preparing polyamide membrane [64].

68 Desalination Updates

Figure 25. Process block flow diagram for preparing PA-6 membrane [65].

**Figure 25.** Process block flow diagram for preparing PA-6 membrane [65].

**Figure 26.** Process block flow diagram for preparing PA-6 membrane [66].

**Figure 28.** Process block flow diagram for preparing PA-6 membrane [68].

**Figure 29.** Process block flow diagram for preparing PA-6 membrane [69].

**Figure 30.** Process block flow diagram for preparing PA-6/Chitosan membrane [70].

### **6. Conclusion**

The preparations of desalination membranes usually involve the phase inversion process, in which a homogeneous casting solution induces phase separation into a polymer-rich phase and a polymer-poor phase by the exchange of solvent with nonsolvent in a coagulation bath. Phase inversion process is the most important technique used to prepare both asymmetric and symmetric polymeric membranes. From a thermodynamic point of view, study on polymer– solvent–nonsolvent system can be well depicted in a ternary phase diagram. The Flory-Huggins theory was found to be a convenient and useful framework for the thermodynamic analysis of component mixing in a membrane preparation system.

In fact, the equilibrium ternary phase diagram system is still a good tool for controlling the membrane morphology and interpreting the membrane structure to be suitable for the required application such as membrane desalination. Significantly, knowledge of phase equilibria (cloud points, binodals, spinodals, and critical compositions) enables one to change the conditions for the preparation of membranes such as the compositions of the casting solution, temperature, and coagulation bath type to obtain an optimum membrane structure. The phase diagram has an important role to report the agreement between experimental work in order to get the required membranes, and the ternary phase diagram miscibility gaps for the evaluations of membrane-forming system.

### **Nomenclature**

**Figure 29.** Process block flow diagram for preparing PA-6 membrane [69].

70 Desalination Updates

**Figure 30.** Process block flow diagram for preparing PA-6/Chitosan membrane [70].

## **Author details**

Ayman Taha Abd El-aziem El-gendi

Address all correspondence to<EMAIL_ADDRESS>
Chemical Engineering & Pilot Plant Department Engineering Research Division, National Research Centre El-Bohouth St., Dokki, Cairo, Egypt

### **References**

SEIP Solvent exchange immersion precipitation

PI Aromatic polyimides such as Kapton™

PPSS Poly (phenylene sulfide sulfone)

PTMSP Poly (1-trimethylsilyl-1-propyne)

CA Cellulose acetate

72 Desalination Updates

PMDA Pyromellic dianhydride PASA Poly (amidesulfonamide) PEAH Polyetheramide hydrazide

PEG Polyethylene glycol

PEI Polyetherimide

PES Polyether sulfone PS Polysulfone

PVA Polyvinyl alcohol

PA Propionic acid PA-6 Polyamide-6

PVDF Polyvinylidenedifluoride

PABH p-Amino benzhydrazide PAH Polyamide hydrazides PAN Polyacrylonitrile PP Polypropylene PPO Polyphenyleneoxide

PTFE Teflon (polytetrafluoro ethylene)

Ayman Taha Abd El-aziem El-gendi

Address all correspondence to<EMAIL_ADDRESS>
Research Centre El-Bohouth St., Dokki, Cairo, Egypt

Chemical Engineering & Pilot Plant Department Engineering Research Division, National

PVAC Poly(vinyl acetate) PVC Poly(vinyl chloride) PVDC Poly(vinylidene chloride)

ZrO2 Zirconium oxide

**Author details**

bution systems to improve organoleptic properties. The case of the Barcelona Metropolitan Area, Journal of Cleaner Production 2014; 69 250–259.

[30] Bulte A., Naafs E., Eeten F., Mulder M., Smolders C., Strathmann H. Equilibrium thermodynamics of the ternary membrane- forming system nylon, formic acid and water, Polymer 1996; 37 1647–1655.

bution systems to improve organoleptic properties. The case of the Barcelona

[17] Frank W, Smolders C, Calculation of liquid-liquid phase separation in a ternary sys‐ tem of a polymer in a mixture of a solvent and a nonsolvent, Macromolecules 1982;

[18] Frommer M., Lancet M A. Reverse Osmosis Membrane Research, In: Lonsdale H K.,

[19] Baker RW., Cussler EL., Eykamp W., Koros WJ., Riley RL., Strathman RH. Membrane separation systems: recent developments and future directions, ndc, Membrane Technology and Research, Noyes Publications, Mill Road at Grand Ave., Park Ridge,

[20] Witte P., Dijkstra P., Berg J., Feijen J. Review phase separation processes in polymer solutions in relation to membrane formation, J. Membr. Sci. 1996; 117 1–31.

[21] Strathmann H. Production of microporous media by phase inversion processes, ACS

[22] Strathmann H. and Koch K. The formation mechanism of phase inversion mem‐

[23] Wijmans J. and Smolders C. Preparation of asymmetric membranes by the phase in‐ version process, In: Londsdale H K. and Pinho M H. (Eds.), Synthetic Membranes: Science, Engineering and Applications, Reidel, Dordrecht, The Netherlands; 1986,

[24] Zeman L. and Fraser T. Formation of air-cast cellulose acetate membranes. Part I.

[25] Zeman L. and Fraser T. Formation of air-cast cellulose acetate membranes. Part II. Ki‐

[26] Scott K., Hughes R. Industrial membrane separation technology, Chapman & Hall:

[27] Loeb M., Sourirajan S. Sea water demineralization by means of an osmotic mem‐

[28] Chun K., Jang S., Kim H., Kim Y., Han H., Joe Y, Effects of solvent on the pore forma‐ tion in asymmetric 6FDA–4, 40ODA polyimide membrane: terms of thermodynam‐ ics, precipitation kinetics, and physical factors, J. Membr. Sci 2000; 169 197–214. [29] Dyukevick A., Yatskova T. Compaction on ultrafiltration membrane under the effect

netics of demixing and microvoid growth, J. Membr. Sci 1994; 87 267.

Metropolitan Area, Journal of Cleaner Production 2014; 69 250–259.

Podall H E. (Eds.)., Plenum Press: New York; 1972, p. 85.

Study of macrovoid formation, J. Membr. Sci 1993; 84 93.

of working pressure, Khim-Tekhnol-Vody, 1991; 13 544–547.

15 1493–1497.

74 Desalination Updates

NJ 07656 (USA) ;1991.

Symp. Ser 1985; 269 165.

pp. 39–56.

London; 1996.

branes, Desalination 1977; 21 241.

brane, Adv. Chem. Ser 1962; 38 117.

[59] Combe C., Molis E., Lucas P., Riley R., Clark M M. The effect of CA membrane prop‐ erties on absorptive fouling by humic acid, J. Membr. Sci 1999; 154 73–87.

[45] Kim I., Yoon H., Lee K. Formation of integrally skinned asymmetric polyetherimide nanofiltration membranes by phase inversion process, J. Appl. Polym. Sci 2002; 84

[46] Shieh J., Chung T S. Phase-inversion poly(ether imide) membranes prepared from water-miscible/immiscible mixture solvents, Ind. Eng. Chem. Res 1999;38 2650–2658.

[47] Smolders C., Reuvers A., Boom R., Wienk I. Microstructures in phase inversion mem‐

[48] Amirilargani M., Sadrzadeh M., Mohammadi T. Synthesis and characterization of

[49] Saljoughi E., Sadrzadeh M., Mohammadi T. Effect of preparation variables on mor‐ phology and pure water permeation flux through asymmetric cellulose acetate mem‐

[50] Frommer M., Messalam R., Mechanism of membrane formation. VI. Convective flows and large void formation during membrane precipitation, Ind. Eng. Chem.,

[51] Strathmann H., Kock K., Amar P., Baker R. The formation mechanism of asymmetric

[52] Tomaszewska M. Preparation and properties of flat-sheet membranes from poly (vi‐ nylidene fluoride) for membrane distillation, Desalination 1996; 104(1-2) 1–11.

[53] Ruiting H., Zhenya G., Kaijie Z. and Guangming Z., Preparation and properties of PVDF-fabric composite membrane for membrane distillation, Desalination 2009;

[54] Chunsheng F., Baoli S., Guomin L. and Yonglie W., Preparation and properties of mi‐ croporous membrane from poly (vinylidene fluoride-co-tetrafluoroethylene) (F2.4)

[55] Ortiz J M., Peria L., Mengual L J. Characterization of membrane distillation prepared

[56] Na T., Qian J., Huanju Z., Jinjin L., Sha C. Preparation and morphological characteri‐ zation of narrow pore size distributed polypropylene hydrophobic membranes for vacuum membrane distillation via thermally induced phase separation, Desalination

[57] Khayeta M., Menguala J I., Matsuura T. Porous hydrophobic/hydrophilic composite membranes Application in desalination using direct contact membrane distillation, J.

[58] Qtaishat M., Rana D., Khayet M., Matsuura T. Preparation and characterization of novel hydrophobic/hydrophilic polyetherimide composite membranes for desalina‐ tion by direct contact membrane distillation, J. Membr. Sci 2009; 327(1-2) 264–273.

for membrane distillation, J. Membr. Sci 2004; 237(1-2) 15–24.

by phase inversion, Desalination 1995; 100 139–148.

branes. Part 1. Formation of macrovoids, J. Membr. Sci 1992; 73 259–275.

polyethersulfone membranes, J Polym Res 2010; 17 363–377.

branes, J. Membr.Sci 2009; 326 627–634.

membranes, Desalination 1975; 16 179–203.

Prod. Res. Dev 1973; 12 328–333.

249(3) 910–913.

2010 ; 256(1-3) 27–36.

Membr. Sci 2005; 252 101–113.

1300–1307.

76 Desalination Updates

**Alternative Power for Desalination**