Concentration of Anions by Silica Adsorbents with Immobilized Nitrogen-containing Polymers

Immobilization of a polyionene complex on a silica gel surface immediately after polymer formation (in situ immobilization) and the covalent anchorage of polyhexamethylene guanidine hydrochloride onto an amino-containing silica surface have been performed. The adsorption properties of the modified silica adsorbents with respect to Cr(IV), Mo(VI), W(VI), As(V), P(V) and V(V) anions were studied. Silica gels with chemically-bound polyhexamethylene guanidine hydrochloride effected the quantitative removal of V(V), W(VI), Mo(VI) and As(V) anions from their acidic (pH = 2-4) and neutral solutions, although their kinetic characteristics were closer to those of polymeric sorbents. Silicas with in situ immobilized polyionene complexes quantitatively extracted As(V), W(VI) and Mo(VI) anions, and exhibited a high adsorption activity towards Cr(IV), P(V) and V(V) anions from acidic (pH = 1-4) media with adsorption equilibrium being attained at a high rate. The adsorbents synthesized exhibited high adsorption capacities towards the anions investigated.