Sunlight assisted photodecolorization of crystal violet catalyzed by CdS nanoparticles embedded on zeolite A

Zeolite A was prepared from waste porcelain as a cheap source of Si. Cadmium sulfide nanoparticles were prepared by a precipitation process after ion exchange of Cd2+ into the zeolite A. Fourier Transformation Infrared (FT-IR), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) methods were applied for the characterization of samples. The prepared composite was used as a catalyst in the photodecolorization process of crystal violet dye in aqueous solution under sunlight radiation. UV–vis spectrophotometric measurements were performed to determine the extent of decolorization and mineralization. The extent of mineralization was also confirmed by Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) concentration determination and High Performance Liquid Chromatography (HPLC) methods. Considering the influence of experimental parameters such as catalyst concentration, dye concentration, solution pH, and temperature, the dye photoelimination process was studied. The optimal operation parameters were found as follows: pH 9, 1 g L−1 of catalyst loading and 20 ppm of the dye concentration. Zeolite A and naked CdS nanoparticles did not show a remarkable decolorization efficiency. The decolorization process obeyed first-order kinetics.

Research Highlights► Waste porcelain is a cheap source for synthesis of zeolite A. ► Aqueous solution of crystal violet was degraded by CdS incorporated in zeolite A under sunlight irradiation. ► CdS inside the zeolite is active center for degradation.