Comparison Study of Adsorption of Lead and Methylene Blue on Zeolite, Activated Carbon and Their Composite Materials

Abstract

In this study, composite materials consisting of Activated Carbon (AC) and Zeolite were prepared for application in the removal of methylene blue and lead from an aqueous solution. The optimum synthesis method involves the use of metakaolinization and zeolitization, in the presence of activated carbon from kaolin, to form Zeolite. First, Kaolin was thermally activated into amorphous kaolin (metakaolinization); then the resultant metakaolin was attacked by alkaline, transforming it into crystalline zeolite (zeolitization). Using nitrogen adsorption and SEM techniques, the examination and characterization of composite materials confirmed the presence of a homogenous distribution of Zeolite throughout the activated carbon. It has also shown the carbonization process did not destroy the crystalline structure of the zeolite, which was revealed to be intact. Experiments in batch mode were conducted (using three differently-prepared composites, zeolite and activated carbon), to investigate the removal of methylene blue and lead from the aqueous solution of the sorbents. Key experimental parameters (initial concentration, pH, contact time and adsorbent dosage) from the obtained results were measured and analysed. Freundlich and Langmuir models were used to describe the adsorption isotherms, and the observed adsorption kinetic adhered to pseudo-second order.