Sorption Kinetics of Arsenic onto Iron-Conditioned Zeolite

Abstract

Iron-conditioned zeolite was prepared and used in arsenic removal from groundwater at pH 7.8 ± 0.2 and temperature 293 ± 1 K. The effects of initial arsenic concentration and intermittent agitation were investigated in a batch reaction vessel. Kinetics analysis showed that the adsorption reaction between arsenic and the binding surfaces (probably hydrous ferric oxide) can be approximated by a pseudo-second order rate equation and that chemical reaction is the essential rate-controlling step. The rate constant, the equilibrium sorption capacity and the initial arsenic sorption rate were calculated. The initial arsenic uptake and equilibrium uptake increased with an increase in initial concentration. The intermittent agitation was superior in arsenic uptake, compared to continuous agitation. The external and intra-particle diffusion resistances to mass transfer slightly varied with an increase in initial arsenic concentration.