Removal of Paraquat Pesticide from Aqueous Solutions Using a Novel Adsorbent Material Based on Polyacrylamide and Methylcellulose Hydrogels

This research studied the characteristics of poly(acrylamide) and methylcellulose (PAAm-MC) hydrogels as a novel adsorbent material for removal of pesticide paraquat, from aqueous solution, with potential applications in curbing environmental risk from such herbicides. PAAm-MC hydrogels with different acrylamide (AAm) and MC concentrations were prepared by a free-radical polymerization method. The capability of the hydrogels in removing paraquat dichloride from aqueous solution was determined using UV-Vis analysis. The scanning electron microscopy method was used to study the morphological properties of the hydrogels, and swelling degree (Q) of the hydrogels was also measured. The entrapped MC in PAAm chains provoked significant changes in morphological, hydrophilic, and adsorption properties of the PAAm-MC hydrogels. The adsorption capacity of hydrogels was strongly influenced by AAm, MC, and paraquat concentrations with the highest adsorption capacity (q(eq) = 14.3 mg g(-1)) was observed for hydrogels synthesized with 6.0%, AAm with 0.75%, MC swollen in 45.7 mg L-1 of paraquat Solution. Freundlich model performed better than Langmuir model in describing the adsorption isotherm of PAAm-MC/paraquat system, implying a heterogeneous surface. These results suggest that PAAm-MC hydrogels are potentially viable absorbents for removal of paraquat pesticide from aqueous solution and cleaning water contaminated with dyes, heavy metals, and others pesticides. (C) 2009 Wiley Periodicals, Inc. journal of Appl Polym Sci 114:2139-2148, 2009