Adsorption and Photocatalytic Degradation of Crystal Violet Dye under Sunlight Irradiation Using Natural and Modified Clays by Zinc Oxide

A ZnO-supported natural volcanic Algerian clay (ZnO/CNA) was synthesized through an impregnation method to prepare a photocatalytic adsorbent integrated. The discoloration of crystal violet dye (CV) from an aqueous solution was carried out using natural and modified clays via zinc oxide by adsorption and photocatalytic degradation. The materials were characterized through X-ray fluorescence spectrometer (XRF), Scanning electronic microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The effects of diverse experimental parameters on the adsorption process efficiency were investigated. The photocatalysis process of CV was executed by the ZnO/CNA material under sunlight irradiation. The characterization results informed that ZnO nanoparticles were well dispersed on the clay surface (CNA). The adsorption experiments were well clarified via the kinetic model of pseudo-second-order and isotherm model of Langmuir with correlation coefficients (R۲ > ۰.۹۹). Moreover, thermodynamic data showed that CV adsorption was endothermic, spontaneous, and physical. The adsorption capacity of CV was high utilizing ZnO/CNA material and gives ۷۴.۶۳ mg/g by the Langmuir equation. The photodegradation kinetics followed pseudo-۱st order approximate the model of Langmuir-Hinshelwood. The discoloration efficiency with the ZnO/CNA (∼ ۹۲%) was higher compared with the CNA (۶۷%), clearly suggesting promoting effect of ZnO.