In situ synthesis of ZnS nanoparticles onto cellulose/chitosan sponge for adsorption-photocatalytic removal of Congo red.

Developing an efficient and sustainable approach for removing dyes from wastewater remains a challenge. Herein, we report a facile and reliable strategy to create ZnS nanoparticles (NPs) supported by cellulose/chitosan sponge (ZnCCSs) via hydrothermal decomposition of xanthates and in situ synthesis of ZnS NPs. ZnCCSs demonstrate high porosity, low bulk density, outstanding compressibility, and uniformly immobilized ZnS NPs. Benefiting from the affinity sites of polysaccharide sponge skeleton and highly exposed ZnS NPs, ZnCCSs show an excellent synergistic effect of adsorption and photocatalytic degradation performances in removing Congo red pollutants. By regulating the structure through the ratio of components, ZnCCSs show a high removal ratio of 96.53% and excellent stability after reusability cycles. The adsorption and degradation behavior and the photodegradation mechanism are also investigated through trapping experiments. This study provides a promising way of removing dye contaminants through a combination of various mechanisms.