Removal of As (V) from Water with Cryogels Prepared By Molecular Imprinting Technique

Abstract

The aim of this study is to selectively remove As(V) ions, the most common type of arsenic in drinking water and especially surface water. For this purpose, a super macroporous polymeric cryogel column was prepared using the molecular imprinting technique. MAC was chosen as the functional monomer due to the high affinity of arsenic to sulfhydryl (-SH) functional groups. MAC monomer was synthesized from the amino acid cysteine. Physicochemical properties of HEMA-based synthesized poly(HEMA-MAC) cryogel were determined by SEM FTIR surface area and swelling. Adsorption studies from water were carried out in a continuous system. Different parameters such as pH, flow rate, temperature, ionic strength and time were studied to determine the optimum conditions for the removal of As(V) ion from water. The maximum As(V) removal of poly(HEMA-MAC) cryogel was 189.4µg/g polymer at pH: 5.0 and 15ppm concentration. In selectivity studies conducted in the presence of PO43-, SO42- and NO3- ions. According to the relative k values obtained from the selectivity experiments, As IIP cryogel shows 1.52 times more selectivity for As(V) ion than PO43- ion, 2.61 times more selectivity for SO42- ion and 1.53 times more selectivity for NO3- ion than NIP cryogel. From the theoretical calculations, it was found that the As (V) adsorption was fit with the Langmuir isotherm and the adsorption process obeyed pseudo-second order kinetics.