Exploitation of industrial solid wastes for preparing zeolite as a valueadded product and its kinetics as adsorbent for heavy metal ions

Abstract

Aluminum and fumed silica as solid industrial wastes were converted to zeolite NaP as a value-added product without any template. The hydrothermal process was optimized using static autoclave. The crystallization was carried out at 100, 120 and 150°C for 24, 48 and 72 h. The prepared zeolite of Si:Al ratio of 1.2 was characterized using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) provided with Energy Dispersive Spectroscopy (EDS), Surface Area, Fourier Transmitted Infra-Red (FTIR) and Thermal Analysis (TG-DSC). The crystalline phase was formed at 100°C after 72 hours and at 120°C after 48 hours, while it was formed after 24 h only at 150°C. Increasing temperature and time lead to the conversion of the prismatic gibbsite crystals into plate-like structure of zeolite which is then formed cauliflower-like structure. The prepared zeolite was employed as adsorbent for Ni2+ and Cu2+ ions from aqueous solution. The kinetic studies of adsorption processes were performed.