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

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 Bi 2 O 3 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*Bi 2 O 3 @BiVO 4 , 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*Bi 2 O 3 @BiVO 4 was 0.906 h −1 and 84.86%, respectively. The degradation pathway of AO7 was also revealed. The improved photocatalytic performance of the Bi 2 O 3 @BiVO 4 could be attributed to the p-n heterojunction, excitating ·O 2 − 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.