Synthesis of zeolite/activated carbon composite material for the removal of lead (II) and cadmium (II) ions

Abstract The present study reports the feasibility of synthesis of a new composite material containing zeolite (ZSM‐5) and activated carbon that was prepared from custard apple shell powder. The process consisted of the following steps: preparation of activated carbon and subsequent steam assisted dry gel conversion of tetraethyl orthosilicate and sodium aluminate to ZSM‐5 and ZSM‐5 activated carbon composite. The resulting composite materials were characterized by X‐ray diffraction, scanning electron microscope, and Brunauer–Emmett–Teller techniques. The co‐ordination of the alumina incorporated was analyzed using Al magic angle spinning nuclear magnetic resonance. A comparative study among ZSM‐5, ZSM‐5 activated carbon composite, and mechanical mixture was executed toward sequestration of Pb 2+ and Cd 2+ ions from aqueous solution. The ZSM‐5/activated carbon composite exhibited higher sequestration efficiency of lead (Pb 2+ ) and cadmium (Cd 2+ ) from aqueous solution and further from industrial effluents compared to other two sorbents. The ZSM‐5/activated carbon composite exhibited selective adsorption toward Pb 2+ ions compared to Cd 2+ ions and other divalent metal ions.