Improved metal affinity of chelating adsorbents through graft polymerization

Modification of cellulose for heavy metal adsorption was conducted by the g raft polymerization of glycidyl methacrylate utilizing eerie ammonium nitra te initiator, followed by the reaction with polyethyleneimine to introduce nitrogenous ligands. Infrared (IR) spectra of the reaction intermediates an d products qualitatively revealed the presence of significant functional gr oups. Low amine to epoxide ratio (2 amines/epoxide) from elemental analysis of the products confirmed the occurrence of crosslinking between PEI and p oly(GMA) side chain. Comparisons between metal adsorption isotherms of poly (CGMAPEI) adsorbent and cellulose-PEI, a previously synthesized adsorbent h aving extensive PEI crosslinking with the matrix, showed a higher metal aff inity in the former. Based on these properties, an adsorbent structure mode l where ligands acquire an improved mobility was suggested. Optimization ex periments Further revealed that the metal affinity of the this adsorbent is affected by the amount of initiator during polymerization. (C) 1999 Elsevi er Science Ltd. All rights reserved.