Synthesis of porous acrylonitrile/methyl acrylate copolymer beads by suspended emulsion polymerization and their adsorption properties after amidoximation.

Porous acrylonitrile (AN)/methyl acrylate (MA) copolymer beads were prepared by suspended emulsion polymerization. The cyano groups in AN/MA copolymer beads were converted to amidoxime (AO) groups by reaction with hydroxylamine hydrochloride (NH(2)OH.HCl) to remove metal ions in aqueous solution. The untreated AN/MA and amidoximated AN/MA (AO AN/MA) copolymer beads were characterized by FTIR spectroscopy, SEM, and porous structural analysis. Both mesopores and macropores were presented in AN/MA and AO AN/MA copolymer beads. Qualitative experiments of adsorption were conducted to evaluate modified and unmodified resins on fixing Hg(2+), Ag(+), Cu(2+), Fe(3+) and Pb(2+) from aqueous solution using batch extractions. It was found that AO AN/MA copolymer beads have excellent adsorption capacities for Hg(2+), Ag(+) and Cu(2+), especially for Hg(2+), and it have good selectivity for Hg(2+). The equilibrium was established in 10h through adsorption kinetics study. The Langmuir model was much better than the Freundlich model to describe the isothermal process. (c) 2009 Elsevier B.V. All rights reserved.