@article{UnuabonahOluOwolabiTaubertetal.2013, author = {Unuabonah, Emmanuel I. and Olu-Owolabi, Bamidele I. and Taubert, Andreas and Omolehin, Elizabeth B. and Adebowale, Kayode O.}, title = {SAPK a novel composite resin for water treatment with very high Zn2+, Cd2+, and Pb2+ adsorption capacity}, series = {Industrial \& engineering chemistry research}, volume = {52}, journal = {Industrial \& engineering chemistry research}, number = {2}, publisher = {American Chemical Society}, address = {Washington}, issn = {0888-5885 (print)}, doi = {10.1021/ie3024577}, pages = {578 -- 585}, year = {2013}, abstract = {A new sulfonated aniline-modified poly(vinyl alcohol)/K-feldspar (SAPK) composite was prepared. The cation-exchange capacity of the composite was found to be S times that of neat feldspar. The specific surface area and point of zero charge also changed significantly upon modification, from 15.6 +/- 0.1 m(2)/g and 2.20 (K-feldspar) to 73.6 +/- 0.3 m(2)/g and 1.91 (SAPK). Zn2+, Cd2+, and Pb2+ adsorption was found to be largely independent of pH, and the metal adsorption rate on SAPK was higher than that on neat feldspar. This particularly applies to the initial adsorption rates. The adsorption process involves both film and pore diffusion; film diffusion initially controls the adsorption. The Freundlich and Langmuir models were found to fit metal-ion adsorption on SAPK most accurately. Adsorption on neat feldspar was best fitted with a Langmuir model, indicating the formation of adsorbate monolayers. Both pure feldspar and SAPK showed better selectivity for Pb2+ than for Cd2+ or Zn2+.}, language = {en} } @article{OmorogieBabalolaUnuabonahetal.2014, author = {Omorogie, Martins O. and Babalola, Jonathan O. and Unuabonah, Emmanuel I. and Gong, Jian R.}, title = {Hybrid materials from agro-waste and nanoparticles: implications on the kinetics of the adsorption of inorganic pollutants}, series = {Environmental technology}, volume = {35}, journal = {Environmental technology}, number = {5}, publisher = {Routledge, Taylor \& Francis Group}, address = {Abingdon}, issn = {0959-3330 (print)}, doi = {10.1080/09593330.2013.839747}, pages = {611 -- 619}, year = {2014}, abstract = {This study is a first-hand report of the immobilization of Nauclea diderrichii seed waste biomass (ND) (an agro-waste) with eco-friendly mesoporous silica (MS) and graphene oxide-MS (GO+MS ) nanoparticles, producing two new hybrid materials namely: MND adsorbent for agro-waste modified with MS and GND adsorbent for agro-waste modified with GO+MS nanoparticles showed improved surface area, pore size and pore volume over those of the agro-waste. The abstractive potential of the new hybrid materials was explored for uptake of Cr(III) and Pb(II) ions. Analysis of experimental data from these new hybrid materials showed increased initial sorption rate of Cr(III) and Pb(II) ions uptake. The amounts of Cr(III) and Pb(II) ions adsorbed by MND and GND adsorbents were greater than those of ND. Modification of N. diderrichii seed waste significantly improved its rate of adsorption and diffusion coefficient for Cr(III) and Pb(II) more than its adsorption capacity. The rate of adsorption of the heavy metal ions was higher with GO+MS nanoparticles than for other adsorbents. Kinetic data were found to fit well the pseudo-second-order and the diffusion-chemisorption kinetic models suggesting that the adsorption of Cr(III) and Pb(II) onto these adsorbents is mainly through chemisorption mechanism. Analysis of kinetic data with the homogeneous particle diffusion kinetic model suggests that particle diffusion (diffusion of ions through the adsorbent) is the rate-limiting step for the adsorption process.}, language = {en} } @article{UnuabonahGuenterWeberetal.2013, author = {Unuabonah, Emmanuel I. and G{\"u}nter, Christina and Weber, Jens and Lubahn, Susanne and Taubert, Andreas}, title = {Hybrid Clay - a new highly efficient adsorbent for water treatment}, series = {ACS sustainable chemistry \& engineering}, volume = {1}, journal = {ACS sustainable chemistry \& engineering}, number = {8}, publisher = {American Chemical Society}, address = {Washington}, issn = {2168-0485 (print)}, doi = {10.1021/sc400051y}, pages = {966 -- 973}, year = {2013}, abstract = {New hybrid clay adsorbent based on kaolinite clay and Carica papaya seeds with improved cation exchange capacity (CEC), rate of heavy metal ion uptake, and adsorption capacity for heavy metal ions were prepared. The CEC of the new material is ca. 75 meq/100 g in spite of the unexpectedly low surface area (approximate to 19 m(2)/g). Accordingly, the average particle size of the hybrid clay adsorbent decreased from over 200 to 100 pm. The hybrid clay adsorbent is a highly efficient adsorbent for heavy metals. With an initial metal concentration of 1 mg/L, the hybrid clay adsorbent reduces the Cd2+, Ni2+, and Pb2+ concentration in aqueous solution to <= 4, <= 7 and <= 20 mu g/L, respectively, from the first minute to over 300 min using a fixed bed containing 2 g of adsorbent and a flow rate of approximate to 7 mL/min. These values are (with the exception of Pb2+) in line with the WHO permissible limits for heavy metal ions. In a cocktail solution of Cd2+, and Ni2+, the hybrid clay shows a reduced rate of uptake but an increased adsorption capacity. The CEC data suggest that the adsorption of Pb2+, Cd2+, and Ni2+ on the hybrid clay adsorbent is essentially due to ion exchange. This hybrid clay adsorbent is prepared from materials that are abundant and by a simple means that is sustainable, easily recovered from aqueous solution, nonbiodegradable (unlike numerous biosorbent), and easily regenerated and is a highly efficient alternative to activated carbon for water treatment.}, language = {en} } @article{UnuabonahElKhaiaryOluOwolabietal.2012, author = {Unuabonah, Emmanuel I. and El-Khaiary, Mohammad I. and Olu-Owolabi, Bamidele I. and Adebowale, Kayode O.}, title = {Predicting the dynamics and performance of a polymer-clay based composite in a fixed bed system for the removal of lead (II) ion}, series = {Chemical engineering research and design}, volume = {90}, journal = {Chemical engineering research and design}, number = {8}, publisher = {Inst. of Electr. and Electronics Engineers}, address = {Rugby}, issn = {0263-8762 (print)}, doi = {10.1016/j.cherd.2011.11.009}, pages = {1105 -- 1115}, year = {2012}, abstract = {A polymer-clay based composite adsorbent was prepared from locally obtained kaolinite clay and polyvinyl alcohol. The composite adsorbent was used to remove lead (II) ions from aqueous solution in a fixed bed mode. The increase in bed height and initial metal ion concentration increased the adsorption capacity of lead (II) and the volume of aqueous solution treated at 50\% breakthrough. However, the adsorption capacity was reduced by almost 16.5\% with the simultaneous presence of Ca2+/Pb2+ and Na+/Pb2+ in the aqueous solution. Regeneration of the adsorbent with 0.1 M of HCl also reduced its adsorption capacity to 75.1\%. Adsorption of lead (II) ions onto the polymer-clay composite adsorbent in the presence of Na+ and Ca2+ electrolyte increased the rate of mass transfer, probably due to competition between cationic species in solution for adsorption sites. Regeneration further increased the rate of mass transfer as a result of reduced adsorption sites after the regeneration process. The length of the mass transfer zone was found to increase with increasing bed height but did not change with increasing the initial metal ion concentration. The models of Yoon-Nelson, Thomas, and Clark were found to give good fit to adsorption data. On the other hand, Bohart-Adams model was found to be a poor predictor for the column operation. The polymer-clay composite adsorbent has a good potential for the removal of lead (II) ions from highly polluted aqueous solutions.}, language = {en} } @article{OmorogieBabalolaUnuabonahetal.2012, author = {Omorogie, Martins O. and Babalola, Jonathan O. and Unuabonah, Emmanuel I. and Gong, Jian Ru}, title = {Kinetics and thermodynamics of heavy metal ions sequestration onto novel Nauclea diderrichii seed biomass}, series = {BIORESOURCE TECHNOLOGY}, volume = {118}, journal = {BIORESOURCE TECHNOLOGY}, number = {8}, publisher = {ELSEVIER SCI LTD}, address = {OXFORD}, issn = {0960-8524 (print)}, doi = {10.1016/j.biortech.2012.04.053}, pages = {576 -- 579}, year = {2012}, abstract = {This study reports the sequestration of Cd(II) and Hg(II) using a new biosorbent. Nauclea diderrichii seed biomass. Experimental data obtained were fitted into kinetic and thermodynamic models. Experimental data fitted best into pseudo-second order kinetic model among others. Results obtained kinetically revealed that the biosorption of Cd(II) and Hg(II) using N. diderrichii seed biosorbent increased with increase in temperature. At the highest temperature, which was 333 K. the highest amount of metal biosorbed, q(e), for Cd(II) and Hg(II) obtained were 6.30 and 6.15 mg/g respectively. The biosorption of Cd(II) was kinetically faster than that of Hg(II), the highest initial biosorption rates for Cd(II) and Hg(II) were 56.19 and 4.39 mg/g min respectively. Thermodynamic parameters obtained by Erying equation from this study revealed that the biosorption process was spontaneous, feasible, endothermic with a decrease in the degree of chaos in the biosorption system. (C) 2012 Elsevier Ltd. All rights reserved.}, language = {en} } @misc{UnuabonahTaubert2014, author = {Unuabonah, Emmanuel I. and Taubert, Andreas}, title = {Clay-polymer nanocomposites (CPNs): Adsorbents of the future for water treatment}, series = {Applied clay science : an international journal on the application and technology of clays and clay minerals}, volume = {99}, journal = {Applied clay science : an international journal on the application and technology of clays and clay minerals}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0169-1317 (print)}, doi = {10.1016/j.clay.2014.06.016}, pages = {83 -- 92}, year = {2014}, abstract = {A class of adsorbents currently receiving growing attention is the clay-polymer nanocomposite (CPN) adsorbents. CPNs effectively treat water by adsorption and flocculation of both inorganic and organic micropollutants from aqueous solutions. Some of these CPNs - when modified with biocides - also have the ability to efficiently remove microorganisms such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans from water. CPNs are far more easily recovered from aqueous media than neat clay. They also exhibit far better treatment times than either polymer or clay adsorbents. They have higher adsorption capacity and better life cycles compared with clay alone. CPNs therefore show an excellent potential as highly efficient water and waste treatment agents. This article reviews the various CPNs that have been prepared recently and used as adsorbents in the removal of micropollutants (inorganic, organic and biological) from aqueous solutions. A special focus is placed on CPNs that are not only interesting from an academic point of view but also effectively reduce the concentration of micropollutants in water to safe limits and also on new developments bordering on CPN use as water treatment agent that have not yet realized their full potential. (C) 2014 Elsevier B.V. All rights reserved.}, language = {en} } @misc{UnuabonahNoeskeWeberetal.2019, author = {Unuabonah, Emmanuel I. and N{\"o}ske, Robert and Weber, Jens and G{\"u}nter, Christina and Taubert, Andreas}, title = {New micro/mesoporous nanocomposite material from low-cost sources for the efficient removal of aromatic and pathogenic pollutants from water}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {720}, doi = {10.25932/publishup-42621}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-426214}, pages = {119 -- 131}, year = {2019}, abstract = {A new micro/mesoporous hybrid clay nanocomposite prepared from kaolinite clay, Carica papaya seeds, and ZnCl2 via calcination in an inert atmosphere is presented. Regardless of the synthesis temperature, the specific surface area of the nanocomposite material is between ≈150 and 300 m2/g. The material contains both micro- and mesopores in roughly equal amounts. X-ray diffraction, infrared spectroscopy, and solid-state nuclear magnetic resonance spectroscopy suggest the formation of several new bonds in the materials upon reaction of the precursors, thus confirming the formation of a new hybrid material. Thermogravimetric analysis/differential thermal analysis and elemental analysis confirm the presence of carbonaceous matter. The new composite is stable up to 900 °C and is an efficient adsorbent for the removal of a water micropollutant, 4-nitrophenol, and a pathogen, E. coli, from an aqueous medium, suggesting applications in water remediation are feasible.}, language = {en} }