Removal of trace As(V) from aqueous solution by Fe(III)-loaded porous amidoximated polyacrylonitrile

A Fe(III)-loaded chelating resin named Fe(III) AO PAN was prepared by immobilizing Fe(III) onto porous amidoximated polyacrylonitrile (AO PAN) obtained by modification of hydroxylamine with polyacrylonitrile (PAN), which was synthesized by suspended emulsion polymerization. The structures of PAN, AO PAN, and Fe(III)-AO PAN were characterized by infrared spectrometry and scanning electron microscopy. The performance of Fe(III)-AO PAN as the ligand exchange adsorbent to remove As(V) from aqueous solution was investigated using static equilibrium and dynamic adsorption experiments. The adsorption experiments showed that Fe(III)-AO PAN had higher adsorption selectivity for As(V) than other ubiquitous anions in nature water body such as Cl−, SO42−, HCO3−, PO43−, and SiO32−. The optimal pH for adsorption of As(V) on Fe(III) AO PAN was 2.0, with the maximum adsorption capacity of 0.55 mg/g. The As(V) adsorbed on Fe(III) AO PAN could be easily eluted with 10 BV of 5% NaCl solution (at pH = 9.0).