In-situ synthesis of porous PVC/ZnO heterojunction composites for photocatalytic removal of uranium from wastewater

The design and construction of green, efficient, and economical biochar-based materials are critical for the removal of uranium from wastewater. In this study, pumpkin vine biochar (PVC) was pre-activated with ZnCl2 at high temperatures, followed by in-situ transformation of the uniformly distributed ZnCl2 within the pores into ZnO using (NH4)2C2O4, resulting in the successful preparation of the PVC/ZnO heterojunction composite material. The efficient uranium adsorption of PVC/ZnO is enabled by its high specific surface area and abundant adsorption active sites. Additionally, the heterostructure between PVC and ZnO establishes a rapid photoelectron transfer channel, effectively inhibiting the recombination of photogenerated electrons and holes, thereby enhancing photocatalytic efficiency. Experimental results demonstrate that the uranium capture capacity of PVC/ZnO under light irradiation reaches up to 2442.5 mg & sdot;g-1, with an especially notable removal rate exceeding 96 % in mine wastewater. This study provides a novel approach for fabricating modified biochar-based composite materials and paves the way for the development of multifunctional biochar photocatalysis.