Adsorption of arsenite from aqueous solutions by cerium-loaded cation exchange resin

摘要

A new cerium-loaded cation exchange resin adsorbent for arsenite was prepared by impregnating cerium onto cation exchange resin. Batch adsorption experiments under various conditions, such as time, temperature, pH and coexistent ions were carried out to evaluate the adsorption characteristics of Ce-loaded resin in the removal of As(III) from aqueous solutions. The results show that the adsorption kinetics of As(III) obey a pseudo second-order kinetic model and the adsorption rate constant were 0.5215 g mg-1min-1. The adsorption isotherm data for As(III) fitted well to the Langmuir equation model and the adsorption capacity were 2.5297 mg/g. The adsorption of As(III) were found pH sensitive and the optimum pH was found to be 5–6. Except for phosphate ion, the coexistent anionic, such as nitrate, chlorate, sulphate and carbonate, showed no remarkable effect on As(III) adsorption. The desorption and regeneration study showed that the adsorption capacity of Ce-loaded resin for As(III) can be restored to 69.61% with 0.5 M sodium hydroxide solution.