Poly(acrylamide) grafts on spherical polyvinyl pyridine resin for removal of mercury from aqueous solutions

Poly(acrylamide) is grafted onto cross-linked poly (4-vinyl pyridine) (P4-VP) resin "Reillex 425". Its quaternization with potassium chloroacetate results in cross-linked poly (4-vinyl pyridine) having carboxymethyl pyridinium groups. This resin is grafted with acrylamide after redox initiation through the carboxyl groups with cerium ammonium nitrate. The resulting resin with 111.7 wt% of poly(acrylamide) grafts is a high capacity (3.36 mmol g^-1) mercury specific sorbent. Experiments performed under identical conditions with some other ions such as Zn(II), Pb(II), Fe(III) and Cd(II) showed that those metal ions are not sorbed by the resin. Flexible graft chains of poly(acrylamide) provide nearly homogeneous reaction conditions in mercury uptake. Regeneration of the mercury loaded polymer can be achieved by acetic acid treatment.