SORPTION OF HUMIC SUBSTANCES ONTO NATURAL ZEOLITE AND THEIR EFFECT ON ARSENIC IMMOBILIZATION

This paper evaluates the immobilization of humic acids extracted from soils on the surface of natural zeolite clinoptilolite from aqueous solutions and the influence of humic acid coverage on the arsenate immobilization. The kinetics of humic acids sorption onto two different fractions of zeolite was evaluated and Freundlich isotherm was applied for finer fraction (below 0.1 mm). Freundlich constant was 0.002 mg.g(-1) which indicates low affinity of humic acids towards the inorganic material in diluted solutions. The amount of sorbed humic acids slightly decreased the affinity of sorbent for arsenate at pH 7. The sorption capacity for iAs(V) decreased from 10.97 mg.g(-1) to 7.57 mg.g(-1).