Removal of Mn(II), Fe(III) and Cr(III) from aqueous solutions using Bulgarian clinoptilolite (original) (raw)

The main purpose of the present work was to study the adsorption of Mn(II), Fe(III) and Cr(III) from aqueous solutions onto natural and pretreated Bulgarian clinoptilolite from Beli plast deposit. Batch adsorption studies were carried out to evaluate the effect of contact time, temperature, solution pH and initial concentration of investigated ions. The equilibrium adsorption data were fitted to linear Langmuir, Freundlich and Dubinin-Radushkevich models and maximum adsorption capacities were calculated. The adsorption of the investigated ions followed pseudo-second-order reaction kinetics, as well as a Freundlich isotherm. The results clearly showed that the treatment with NaCl improved the adsorption capacity of natural clinoptilolite. It was found that the removal of all investigated ions from a multicomponent aqueous solution was significantly affected by the presence of competing ions.