Rapidly photocatalytic mineralization of typical veterinary drugs with the SnO2/SnIn4S8 composite.

Abstract Considering the high environmental risk, the remediation of veterinary drug pollutants aroused numerous concerning. In this paper, a novel photocatlyst, SnO2/SnIn4S8, was fabricated by in situ precipitation and hydrothermal method and then employed to simulate photocatalytic degradation of olaquindox under visible light. The SEM, TEM, XRD, XPS and electrochemical results clearly showed that the n-type heterojunction between SnO2 and SnIn4S8 was successfully constructed, which greatly reduce the recombination of the photogenic electron and holes, leading to the improvement of photocalytic performance and stability (recycled over 10 times). Besides, the SnO2/SnIn4S8 composite also exhibited good ability to mineralize the olaquindox. Under the optimal condition (pH of 3, 1 g L−1 of 30 wt% SnO2/SnIn4S8 and 10 mg L−1 of initial olaquindox concentration), the olaquindox could be fully and rapidly degraded in 25 min, and completely mineralized in 2 h (99.3 ± 1.7%). LC-QTOF-MS analysis evidently displayed 10 intermediates during the olaquindox degradation. In addition, with the attack of the reactive oxygen species (h+, •OH and •O2−), olaquindox could be effectively decomposed via deoxygenation, hydroxylation and carboxylation reactions. Importantly, compared to photodegradation, the photocatalytic process was an ideal way to eliminate the olaquindox form water because it could avoid the accumulation of toxic byproducts.