Feasibility Study of Cadmium Removal from Water by Cationic Exchange on Clinoptilolite

Clinoptilolite is the most abundant natural zeolite in many countries as well as in Mexico and exhibits a special characteristic such as cation exchange that can be used to remove certain ions from their solutions. In this work this natural zeolite has been examined systematically in order to assess the feasibility of this low cost mineral in removal of Cadmium from contaminated water. It is known Cadmium is a heavy metal and extremely toxic, even at very low concentrations, hence its removal is environmentally essential.

Studies were performed under various conditions such as presence of different cations (Cd2+, Na+ and NH4+), Cd2+ concentrations and times of cation exchange. The removal of Cd2+ from its artificially prepared aqueous solutions was successfully done by cationic exchange mechanism during its interaction with zeolite at room temperature. The concentration of cadmium in solution was determined using Atomic-Absorption Spectroscopy and in zeolite using Scanning Electron Microscopy and X-Ray Photoelectron Spectroscopy, as a function of time of cationic exchange. The results showed that Clinoptilolite is highly effective in Cd2+ removal from water even at higher concentrations than those of relevance to environmental control.