Photocatalytic degradation of Rhodamine 6G using ZnO-montmorillonite nanocomposite: a kinetic approach

摘要

Montmorillonite clay was incorporated with ZnO to get ZnO-montmorillonite nanocomposite. This nanocomposite was successfully used for removal of Rhodamine 6G by photocatalytic degradation and adsorption. The influence of contact time, initial dye concentration, pH and catalyst dose has been determined. Contact time of 80 min and pH 3 was optimized for photocatalytic degradation of Rhodamine 6G. Kinetic parameters like pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion model were determined. Pseudo-second-order kinetics could describe the adsorption kinetics well with r(2) > 0.997 for 20-150 mg/L dye concentrations. Adsorption isotherms like Langmuir and Freundlich isotherm are used to describe the adsorption of dye. The monolayer capacity was observed to be 200 mg/g. Freundlich adsorption isotherm was found to fit better than Langmuir isotherm. Removal of Rhodamine 6G could be increased by combine effect of photocatalytic degradation and adsorption by nanocomposite.