1179 Research Article Received: 19 May 2012 Revised: 30 August 2012 Accepted: 6 September 2012 Published online in Wiley Online Library: 4 December 2012 (wileyonlinelibrary.com) DOI 10.1002/pi.4403 Environmentally friendly copolymeric beads of Chlorella vulgaris and poly(methacrylamide) grafted aliginic acid di-block copolymers for biosorption of zinc ions Mohammad M Fares, a* Fahmi A Abu Al-Rub, b* Munther Kandah b and Hussein Allaboun b Abstract The synthesis of biodegradable environmentally friendly copolymeric beads for water treatment biosorption processes is demonstrated. The synthesized poly(methacrylamide) grafted aliginic acid copolymers were characterized using 1 H NMR, Fourier transform infrared spectroscopy, TGA and SEM. The di-block copolymers showed a morphological change from two-dimensional layer-by-layer structures to three-dimensional well-compacted wrinkles as grafting efficiency increased. The copolymeric beads were formed from the di-block copolymer and algae crosslinked with 5% calcium ions (w/w). These copolymeric beads were then subjected to biosorption investigations for zinc ions as a model heavy metal ion at different pH values and stirring time periods. Batch adsorption experiments showed that the copolymeric beads were effective in zinc ion removal from aqueous solutions with maximum uptake exceeding 89.0 mg g –1 using higher grafting efficiency copolymeric beads at pH 5.5. Equilibrium pH studies revealed that zinc biosorption was pH dependent and maximum uptake was obtained at pH 5.5. Dynamics studies showed that the biosorption of zinc was rapid with equilibrium attained within 40 min and the data followed pseudo-second-order kinetics. The equilibrium biosorption of zinc ions on the copolymeric beads exhibited a Freundlich isotherm fit. c  2012 Society of Chemical Industry Keywords: environmentally friendly; algae; poly(methacrylamide) grafted aliginic acid; copolymeric beads; biosorption INTRODUCTION Industrial and agricultural daily efficacies are usually accompanied by severe environmental lesions and industrial threat. Water pollution is one of the significant industrial epidemics that needs to be well treated and resolved. 1 Various methods and techniques have been developed to resolve such environmental obstacles via purification of water from hazardous metals and/or organic pollutants. The removal and recovery of metals have been successfully implemented using various techniques such as reverse osmosis, 2 electrolysis, 3 chemical precipitation 4 and ion exchangers, 5 which were found to be expensive and not eco-friendly. 6 On the other hand, biosorption, which involves the use of materials of biological origin, has been extensively investigated. Biosorbents such as bacteria, 7 fungi, 8 – 10 agricultural wastes, 11 yeast, 12 pectin 13 and algae 14 – 17 have recently been utilized for the purification of water and for the recovery of metals and/or organic pollutants. The use of such biosorbents brings many advantages such as low cost, environmentally friendly and efficient adsorptivity characteristics. Sodium alginate is a naturally occurring polysaccharide obtained mainly from algae belonging to the Phaeophyceae class and composed of two monomeric units, β -D-mannuronic acid and α-L-guluronic acid. 18 It has been used in various applications such as controlled release of drugs, 19 pesticides, 20 thickening agents, gelling agents and as colloidal stabilizers. 21 Furthermore, sodium alginate and other polysaccharides such as pectin may form three-dimensional network structures when crosslinked with either calcium ions or glutaraldehyde, and consequently could be used in protein release and as drug carriers. 22,23 It has also been used in the enhancement of drug dissolution. 24 The modification of natural polymers via formation of di-block copolymers through grafting not only formed nontoxic, low price material but also showed substantial biodegradability properties. The highly porous structure of these hydrogels could easily be tuned by controlling the density of crosslinks and the degree of hydrophilicity of the gel matrix, which would permit their successful implementation in biosorption and desorption studies. 25,26 Furthermore, cell immobilization is an ∗ Correspondence to: Mohammad M Fares, Department of Chemical Sciences, Faculty of Science and Arts, and Fahmi A Abu Al-Rub, Department of Chemical Engineering, Faculty of Engineering, Jordan University of Science and Technology, PO Box 3030, Irbid 22110, Jordan. E-mail: fares@just.edu.jo; abualrub@just.edu.jo a Department of Chemical Sciences, Faculty of Science and Arts, Jordan University of Science and Technology, PO Box 3030, Irbid, 22110, Jordan b Department of Chemical Engineering, Faculty of Engineering, Jordan University of Science and Technology, PO Box 3030, Irbid, 22110, Jordan Polym Int 2013; 62: 1179–1186 www.soci.org c  2012 Society of Chemical Industry