Lead and Cadmium removal from aqueous solution using an industrial gypsum by-product

Abstract

The valorization of gypsum (by-product of phosphoric acid production) into useful product seems to be of important interest. In this study, the adsorption of lead (II) and cadmium (II) in an aqueous solution using both commercial gypsum (CG) and industrial gypsum byproduct (IG) as adsorbents, has been investigated. The use of highly-purity CG allows the understanding of the adsorption phenomenon. The use of an IG as received from an industrial site allows the evaluation of its reactivity compared to pure CG. The adsorption experiments were carried out at ambient conditions for 24 h and the pH was recorded along the reaction. FTIR analyses were performed in order to examine the modification in the sulfate bound arrangement in the case of use of lead and/or cadmium. The obtained results have shown that the retention capacity of lead (II) and cadmium (II) by IG was similar that those obtained in the case of CG. However, gypsum by-product may be used as an alternative material to remove heavy metals in wastewaters.