Recovery of vanadium from wastewater and in situ preparation of Bi-V-based photocatalyst

Abstract

Vanadium is a kind of heavy metal pollutant listed as priority control by various countries, but it is also a strategic valuable metal. The current treatment of vanadium-containing wastewater suffers from the waste of vanadium resources and produces large volumes of hazardous wastes. An innovative approach was proposed to address these problems. The method involved selectively recovering vanadium from wastewater using Bi2O3 and preparing Bi-V photocatalyst in situ. By optimizing the conditions, the recovery efficiency of pentavalent vanadium (V(V)) was 99.6%. The recovered product was determined to be 1.14*Bi2O3@BiVO4, and it was proved to be a heterojunction structure by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The band gap was calculated to be 2.32 eV by UV–vis analysis. Under visible light, the degradation rate and efficiency of AO7 by 1.14*Bi2O3@BiVO4 was 0.906 h−1 and 84.86%, respectively. The degradation pathway of AO7 was also revealed. The improved photocatalytic performance of the Bi2O3@BiVO4 could be attributed to the p-n heterojunction, excitating ·O2− and ·OH under visible light. Thus, this method solved the problem of both vanadium discharge in wastewater and the difficulty of vanadium resource utilization, and had practical utilization value.