the inappropriate disposal of dyes in waste water constitutes an environmental problem and can cause damage to the ecosystem
wastewater containing dyes cause water pollution by lowering light penetration and photosynthesis and toxicity from heavy metals associated with pigments .
synthetic dyes are widely used in industries such as textiles , leather , paper , and plastics to color final products .
reactive dyes are the most common dyes used due to their advantages , such as bright colors , excellent colorfastness , and ease of application but effluents are highly toxic to aquatic life .
these dyes are mostly resistant to biodegradation and therefore are not removed by conventional treatment techniques .
dyes are colored substances which colored a substrate as they retained in it by adsorption .
these are soluble completely or partially soluble in a media from which they are applied in contrast with pigments .
synthetic dyes have complex aromatic structures which provide them physiochemical , thermal , biological , and optical stability   and used in photographic paper as indicator and as biological stains .
commercial uses of dyes include the coloration of textile paper , leather , wood , inks , fuels , food items and metals .
this dye may cause problems in , respiratory tract , gastrointestinal tract , irritation to skin , and redness of eyes .
prasad et al . studied the biosorption of coomassie brilliant blue by acid treated coir pith in batch mode .
effect of time , initial concentration of dye and initial adsorbent concentration on biosorption was investigated .
the investigation shows that the acid - treated coir pith is better suited for the removal of dyes from the textile industry effluent .  
katarzyna and watala studied a new photometric method for determining the surface area of plants , which relies on the adsorption of coomassie brilliant blue g-250 on the plant surfaces .
the method was applied to a variety of aquatic plants and found to provide a routine procedure to determine plant surface area .
compared to activated carbon and/or carbon fiber adsorption , in this research , the characteristics and mechanism of adsorption were examined with the aim to develop an efficient dyestuff adsorption system using okara .
the amount of the saturation dye adsorption , qm ( mg - dye / g - okara ) obtained from the langmuir adsorption isotherm after 24  h at ph 3 was 197 .
it was found that okara 's adsorption ability is approximately 66 times higher than the ability of activated carbon .
rauf et al . studied three organic dyes namely , coomassie blue , malachite green and safranin orange by adsorption on sand at 298  k. characteristics of local sand sample used as an adsorbent in this work were initially found from the low - temperature adsorption of nitrogen on sand samples at 77  k. conditions for maximum adsorption of these dyes on sand sample were then optimized .
the adsorption behavior of the dyes was also investigated in terms of added cations and anions and it was found that adsorption of coomassie blue and safranin orange decreased substantially in the presence of sulphate , thiosulphate , acetate , potassium , and nickel and zinc ions .
wei et al . studied the interactions of coomassie brilliant blue g-250 ( cbb ) with bovine serum albumin ( bsa ) and 7-globulin at low ph that are investigated by a spectrophotometric method .
it is considered that the binding of cbb to protein is because of the weak interactions ( ionic , van dar waals , hydrogen bonding , and hydrophobic ) .
factors which influence the sensitivity of the cbb protein assay are studied using this method .
ionic strength and acidity are found to have significant effect on the binding of cbb to protein .
the objective of the present study was to assess the ability of locally available bran for the removal of coomassie brilliant blue ( cbb ) .
the study was carried out with the aim to optimize conditions for maximum removal of this dye from aqueous solutions by using wheat bran . besides this , the adsorption data was fitted to various equations to obtain constants related to the equilibrium of the adsorption phenomena .
pure coomassie brilliant blue r-250 was used for the preparation of standard coomassie brilliant blue r-250 stock solution .
the main characteristics of comassie brilliant blue are and max = 580  nm , color index ( c.i ) = 42660 , chemical formula = c45h44n3nao7s2 , and m.w .
= 825.97  g / mol and is insoluble in cold water and slightly soluble in hot water .
wheat has a hard outer layer . when it is processed , this layer becomes a byproduct , and is called bran . in the case of processing wheat to make wheat flour ,
after three days wheat bran was put in oven at 60c for twenty four hours . dried wheat bran was thoroughly washed with distilled water to remove all dirt and was dried at 100c till constant weight .
then the dried wheat bran was grinded and sieved with a 30-mesh sieve , to prepare homogenous particle size .
this biosorbent was again washed with distilled water to remove adhearing dirt and foreign particles .
the average particle size of adsorbents was measured and it was 500  m and bet surface area was measured by the brunauer , emmett and teller ( bet ) method using n2 gas adsorption ( quanta - chrome inst .
, nova 2200e surface area analyzer ) and it was calculated as 8.62  m / g .   100  mg / l comassie brilliant blue stock solution was prepared in distilled water and stored in brown reagent bottles in dark place to prevent oxidation of the dye solution .
various concentrations of comassie brilliant blue solutions ranging from 1 to 10  ppm were prepared from the comassie brilliant blue stock solution in 100  ml measuring flasks .
. with the help of double beam spectrophotometer absorbance of comassie brilliant blue was measured at wavelength of 580  nm in a 1.0  cm matched quartz curettes against a reagent blank ( without soln . ) on through mixing . at this wavelength
the values obtained from this experiment were given in table 1 and graph shown in figure 1 .
the adsorption of comassie brilliant blue on wheat bran was studied by a batch technique . the general method used for these studies
0.1  g of the dried sieved wheat bran was equilibrated with 10  cm of the comassie brilliant blue solution of the known concentration in a stopper pyrex glass flasks at fixed temperature in a shaker for a known period of time .
the flasks containing the weighed amounts of wheat bran and comassie brilliant blue solution were separately kept in the before mixing for a sufficient period of time to attain the desired experimental temperature .
after equilibration the suspension was centrifuged in a stopper tube for 10 minutes at 3500  rpm .
the concentration of comassie brilliant blue in a known volume of the supernatant was determined by spectrophotometrically .
adsorption of comassie brilliant blue on wheat bran was determined in terms of equilibrium concentration ( ce ) , percentage removal p% , adsorption capacity qe determined as , the equilibrium concentration ( ce ) is determined .
the amount adsorbed per unit weight of the wheat bran , x / m , was calculated spectrophotometrically from the initial ( known comassie brilliant blue concentrations ) and final absorbance of the solutions .
the adsorption of c.b.b on wheat was studied as a function of shaking time at 35c .
a sample of 50  cm of c.b.b ( 10  ppm ) solution was taken in nine titration flasks , labeled them from 19 , and shaken with 0.1  g of wheat bran in each flask for different intervals of time ranging from 5  min to 60  min in a shaker .
after 15 minutes all the solutions were filtered and absorbance was determined photometrically at wavelength 560  nm . from it , calculate the equilibrium concentration ( ce ) of c.b.b , percentage removal , and equilibrium time was determined by plotting a graph between different time intervals and percentage removal . 

figure 1 shows the variation of % age adsorption as a function of shaking time .
the result shows that the adsorption of c.b.b on wheat bran is symmetrically time dependant which increases with the shaking time rapidly and gets to an equilibrium stage after 30 minutes which dose not change latter on .
the values of equilibrium concentration ( ce ) and % age adsorption were shown in figure 1 .
as adsorption and desorption occur side by side so after an appropriate time equilibrium takes place .
composition of wheat bran also plays a major role in this regard . at 30 minute ,
the maximum adsorption is observed due to the attractive forces developed between cbb and wb .
after complete adsorption on outer surface , the dye enters to the inner surface via pores .
the adsorption of c.b.b on wheat bran was studied as a function of different ph .
110 , while keeping all other parameters , that are , c.b.b concentration ( 10  ppm ) , shaking time ( 30  min ) .
after equilibration , the suspension was centrifuged for 30 minutes at 3500  rpm . after 15 minutes all the solutions were filtered and absorbance was determined photometrically at wavelength 560  nm . from it , calculate the amount of equilibrium concentration ( ce ) of c.b.b , percentage removal , and determined the adsorption of c.b.b on wheat bran at different ph by plotting a graph between different ph and percentage removal .  
figure 2 shows the variation of equilibrium concentration ( ce ) and percentage removal as a function of different ph .
the result shows that the adsorption of c.b.b on wheat bran increases with increasing ph and attains to maximum at ph 2.0 .
both ce and % age adsorption also increase with increasing ph till ph 2.0 and then decreased sharply .
the values of equilibrium concentration ( ce ) and % age adsorption were shown in figure 2 .
. it may be due to the increased positive charges on the surface of adsorbent that attracts the functional groups of a dye carrying negative charge .
the adsorption of c.b.b on wheat bran was studied as a function of different amount of adsorbent , that is , 0.11.0 
g , while keeping all other parameters that is , c.b.b concentration ( 10  ppm ) , shaking time ( 30  min ) , and ph ( 2.0 ) , of the suspension constant .
calculate the equilibrium concentration ( ce ) of c.b.b and % age adsorption and determine the adsorption of c.b.b on wheat bran at different amount of adsorbent by plotting a graph between different amount of adsorbent and % age adsorption .  
figure 3 shows the variation of % age adsorption as a function of different amount of adsorbent .
the results show that the adsorption of c.b.b on wheat bran increases spontaneously with increasing adsorbent concentration due to availability of greater active sites .
on the basis of these results , 0.1  g/50  cm of c.b.b solution was selected for further studies .
the values of equilibrium concentration ( ce ) and % age adsorption were shown in figure 3 .
the decrease in % age removal of dye with increased amount of adsorbent is due to the fact that adsorption sites remain unsaturated during adsorption reaction .
the adsorption of c.b.b on wheat bran was studied as a function of its different concentrations , that is , 530  ppm , while keeping all other parameters that is , shaking time ( 30  min ) and ph ( 2.0 ) , sorbent concentration ( 0.1  g ) constant .
calculate the equilibrium concentration ( ce ) of c.b.b and % age adsorption and determined the adsorption of c.b.b on wheat bran at its different concentrations by plotting a graph between different concentration of sorbate and % age adsorption .  
figure 4 shows the variation of % age adsorption as a function of different sorbate concentrations .
the results show that the adsorption of c.b.b on wheat bran increases spontaneously with increasing sorbate concentration till 30  ppm and then become constant onward .
% age adsorption increases continuously with increasing c.b.b concentration . on the basis of these results 0.2  g/1000  cm of c.b.b solution
the values of equilibrium concentration ( ce ) and % age adsorption were shown in figure 4 .
the adsorption of c.b.b on wheat bran was studied as a function of different temperature , that are , 30c , 40c , 50c , 60c , 70c , and 80c , while keeping all other parameters that are , c.b.b concentration ( 10  ppm ) , shaking time ( 30  min ) , ph ( 2.0 ) , and sorbent concentration ( 0.1  g ) , constant . from it
calculate the equilibrium concentration ( ce ) of c.b.b and % age adsorption and determined the effect of temperature on adsorption of c.b.b on wheat bran by plotting a graph between different temperature and % age adsorption .  
figure 5 shows the variation of % age adsorption as a function of different temperature .
the results show that the adsorption of c.b.b on wheat bran was increased spontaneously with increasing temperature .
the values of equilibrium concentration ( ce ) and % age adsorption were shown in figure 5 .
increase in adsorption at elevated temperature is due to the enlargement of pore size from where dye adsorbed .
the adsorption of c.b.b on wheat bran was studied as a function of different c.b.b concentration that is , 530  ppm , while keeping all other parameters that are , shaking time ( 30  min ) , ph ( 2.0 ) , and sorbent concentration ( 0.1  g ) constant .
50  cm of c.b.b ( 5  ppm to 30  ppm ) solution was shaken with 0.1  g of wheat bran for 30  min in a shaker .
after 15 minutes , the absorbance was determined photometrically at wavelength 560  nm . then calculated the adsorbed amount of c.b.b and equilibrium concentration ( ce ) and determine the adsorption isotherms c.b.b on wheat bran by plotting a graph between extent of adsorption ( logq ) and equilibrium concentration log ce ( moldm )
the adsorption isotherms were used to investigate the relationship between the concentration of sorbed species and sorption capacity of sorbing species . 

langmuir adsorption isothermlinear form of langmuir adsorption isotherms is shown as follows : 
 ( 1)1qe=1qmax  + 1bqmax1ce 
 qe : sorption capacity , ce : equilibrium concentration , qmax : maximum possible amount of dye that can be adsorbed per unit dry weight of sorbent , b : empirical constant , indicating the affinity of sorbent towards the sorbate . 
 
linear form of langmuir adsorption isotherms is shown as follows : 
 ( 1)1qe=1qmax  + 1bqmax1ce 
 qe : sorption capacity , ce : equilibrium concentration , qmax : maximum possible amount of dye that can be adsorbed per unit dry weight of sorbent , b : empirical constant , indicating the affinity of sorbent towards the sorbate .   a curve 1/qe versus 1/ce has been plotted to investigate the fitting of langmuir model for the equilibrium data of wb - dye sorption a straight line was obtained .
the correlation coefficient r was found to be 0.9732 indicating that the data was fitted well the langmuir model ( figure 6 ) .   from the langmuir plot ,
qmax = 6.410  mg / g and b = 3.502  l / mg .
the characteristics of the langmuir isotherm can be expressed as another constant separation factor or equilibrium parameter given by rl .
( 2)rl=11+klco , 
 where kl is langmuir 's equilibrium constant which is related to the affinity of binding sites and kl = qmax  b. co is the initial dye concentration . according to mckay et al .
is found to be 0.0042636 and again the adsorption is found to be favorable . 

freundlich absorption isothermlinear form of freundlich adsorption isotherms is shown as [ 1618 ] . 

( 3)logqe = logkf+1nlogce , 
 where qe is the equilibrium dye concentration sorbed in sorbent ( mg  g ) ,  ce  is the dye equilibrium concentration in solution ( mg 
kf is freundlich constant related to the sorption capacity , and 1/n is an empirical parameter related to sorption intensity , which varies with heterogeneity of the material .
the value of n is between 01 indicating favorable sorption of cbb   ( figure 7 ) . 
 
( 3)logqe = logkf+1nlogce , 
 where qe is the equilibrium dye concentration sorbed in sorbent ( mg  g ) ,  ce  is the dye equilibrium concentration in solution ( mg 
kf is freundlich constant related to the sorption capacity , and 1/n is an empirical parameter related to sorption intensity , which varies with heterogeneity of the material .
the value of n is between 01 indicating favorable sorption of cbb   ( figure 7 ) .
this equation is used to determine sorption mean energy which enabled us to estimate whether adsorption is carried out by ion exchange mechanism , physisorption or , chemisorptions .
( 4)lnqe = lnqm2,=rtln(1 + 1ce ) , 
 where qm is a theoretical saturation capacity ,  is a constant related with sorption energy , molj ,  is a polonyi potential and is equal to rtln(1 + 1/ce ) .
mean sorption energy e is determined by 
 ( 5)es=12. is calculated from slope of a linear graph lnqe versus  shown in figure 8 .   the value of sorption mean energy is 0.26  kjmol . it is positive and less than 8  kjmol .
the effect of a change in temperature on the sorption system was studied to determine the thermodynamic parameter and to investigate the nature of the process .
thermodynamic parameters for adsorption of c.b.b on wheat bran such as heat of adsorption ( enthalpy change , h ) , entropy change , s , free energy of specific adsorption and g were calculated from the binding constant kc obtained from langmuir plot by using the following equation .
( 6)go=hotso . 
 below is the equation of straight line : 
 ( 7)go=rtlnkd , kd = qece , lnkd=ho2.303rt+so2.303r . 
 for activation energy , following equation
is used 
 ( 8)lnk = lnaea2.303rt.ea can be calculated from slope of a graph lnk versus 1/t as shown in figure 10 .   where r is the gas constant , kc is the equilibrium constant , t is the temperature ( k ) , co is the equilibrium concentration of c.b.b on adsorbent ( mg / l ) , and ce is the equilibrium concentration of c.b.b in the solution ( mg / l ) .
the values of thermodynamic parameters h and s for the c.b.b . on wheat bran calculated from above equations
the negative values of g indicates the spontaneous nature of adsorption . as the temperature increases , the g values increase , indicating more driving force and hence resulting greater adsorption capacity at higher temperatures .
the lagergrens kinetics equation has been most widely used for the adsorption of an adsorbate from an aqueous solution .
the model is based on the assumption that rate is directly proportional to the number of free sites according to lagergren equation : 
 ( 9)log(qeqt)=logqekt2.303 . 

linear plot of log ( qe  qt ) versus t was plotted to evaluate this kinetic model and to determine rate constant k. the values of r and k are 0.469 and 0.002073 , respectively , shown in figure 11 .
it depicts that lagergren model is not fitted in sorption of cbb on wb .  
the pseudo - second - order model is based on the biosorption followed by second - order mechanism nearby the rate of sorption is proportional to the square of number of unoccupied sites and can be represented as 
 ( 10)tq=1k2qe2+tqt . 

the parameters qe and k2 are calculated from slope and intercept of a plot t / qe versus time shown in figure 12 . the value of r is 0.8396 that shows pseudo - second - order model is best fitted .
the result of this study indicates that wb is an effective sorbent for the uptake of toxic dye from aqueous solution .
the optimum parameters for equilibrium study are time of contact 30  min , ph 2 , and dose of w.b 2  gl under optimum conditions .
the sorption of cbb dye by wb followed a monolayer sorption model langmuir isotherm rather than multilayer model .
 the sorption studies of coomassie brilliant blue ( cbb ) from aqueous solution have been carried out on wheat bran ( wb ) . 
 coomassie brilliant blue on wheat bran was used to study the adsorption behavior under various parameters such as ph , dosage amount , and contact time . 
 it was observed that under optimized conditions up to 95.70% dye could be removed from solution onto wb . 
 langmuir and freundlich adsorption isotherms were used to elaborate the results . 
 freundlich model was found to be fitted well and favored multilayer adsorption . 
 the freundlich constants n and kf were determined as 0.53 and 2.5  104 . 
 thermodynamic parameters such as g , h , and s studied were taking into account , showed spontaneous and favorable reaction for coomassie brilliant blue on wheat bran . 
 the maximum adsorption capacity qm was found to be 6.410  mg / g . 
 the investigations show that non treated wb is a low - cost adsorbent for the removal of dyes from textile industry effluents . 
1. Introduction
2. Materials and Experimental Procedure
3. Conclusion