Efficient tetracycline degradation by MoS2/CuS composite catalyst activated peroxydisulfate in batch and continuous-flow reactors.

A facile one-step hydrothermal method was used to obtain MoS 2 /CuS composite catalyst, which was analyzed using multiple characterization techniques, such as XRD, SEM, TEM, SAD, FT-IR and XPS. As-prepared MoS 2 /CuS showed an enhanced peroxydisulfate (PDS) activation performance for tetracycline (TC) elimination compared with MoS 2 and CuS in a batch reactor. The incorporation of MoS 2 and CuS possess more active sites and low-valent S substances to facilitate the circulation of Mo6+/Mo4+ and Cu2+/Cu+, thus promoting PDS activation and TC degradation. Mechanistic studies demonstrated that the free radical (SO 4 •−, ∙ OH and O 2 •−) and non-free radical (1O 2) oxidation pathways collectively led to TC degradation in MoS 2 /CuS-PDS system, and 1O 2 played a primary role. The impact of important operating factors on TC elimination, the pathways of TC degradation and the toxicity of degradation intermediates were investigated. To facilitate the practical application of MoS 2 /CuS catalyst, it was uniformly loaded onto polyurethane (PU) sponge with a rich pore structure. As-obtained MoS 2 /CuS@PU catalytic sponge activating PDS could efficiently remove TC from the different water matrices in a continuous flow reactor; moreover, MoS 2 /CuS@PU can maintain a high level of stability after 20 h of continuous operation. [ABSTRACT FROM AUTHOR]