Removal of silver (I) from aqueous solutions with clinoptilolite

The aim of the present work was to investigate the ability of natural zeolite, clinoptilolite, to remove silver ions from aqueous solution. Towards this aim, batch adsorption experiments were carried out and the effect of various parameters on this removal process has been investigated. The effects of pH, adsorption time, metal ion concentration and the acidic treatment on the adsorption process were examined. The optimum pH for adsorption was found to be 4.0. It was found that acid treatment has a substantial effect on the metal uptake. In adsorption studies, residual Ag+ concentration reached equilibrium in a short duration of 45 min. Maximum adsorption capacity, 33.23 mg Ag+/g zeolite, showed that this adsorbent was suitable for silver removal from aqueous media. Adsorption phenomena appeared to follow Langmuir and Freundlich isotherms.