Photocatalytic degradation of methyl blue in water using sawdust-derived cellulose nanocrystals-metal oxide nanocomposite

Abstract

The increase in dye-containing effluents that are discharged into the environment and the need to remediate the water bodies from the adverse effect of these dye pollutants have motivated a lot of research work. In this study, ZnO and TiO2 heterojunction systems (MO) embedded in cellulose nanocrystals (CNC), derived from sawdust, are reported. The nanocomposites (CNC/MO) were subsequently used as photocatalyst for the degradation of methyl blue (MB). The nanocomposites were characterized using SEM/EDs, XRD, and the degradation of MB were determined by UV-vis spectrophotometer. The XRD analysis showed characteristic peaks of CNC and the metal oxide (MO) upon the nanocomposite formation. A reduction in the intensity of peak at 30°, attributed to the cellulose 1β phase of pristine CNC, was observed. The morphological evaluation revealed that the nanocomposite exhibited intertwined spherical and rod-like shape on the surface. The effects of some key operating parameters, such as initial pH, catalyst dosage, and initial dye concentration on the degradation of MB were investigated. Higher degradation percentage (98.52%) of MB was observed for the CNC/MO at optimum pH 6. The adopted kinetics models showed that MB degradation was well described by the pseudo-second order model. The application of this nanocomposites in real industrial sample will confirm its robustness.