FeOCl/WS2 composite as a heterogeneous Fenton catalyst to efficiently degrade acid orange II

Heterogeneous photo-Fenton technology has been commonly used in the field of wastewater treatment because it is eco-friendly to the environment and does not produce iron mud. However, the efficiency of photogenerated charge separation and transfer is not ideal, which greatly limits the catalytic activity of photo-Fenton materials. FeOCl/WS2 composites with a visible light response was synthesized by calcination using ferric chloride hexahydrate and tungsten disulfide and their catalytic activity was investigated using acid orange II (AO-II) as the target pollutant. The removal efficiency of AO-II by FeOCl/WS2 composite under different reaction conditions (including weight ratios of FeOCl and WS2, initial pH, temperature, H2O2 consumption, and catalyst dose) were investigated. Photo-degradation tests displayed that when the weight ratio of FeOCl and WS2 was 1:2 (F1W2), the removal efficiency of AO-II by FeOCl/WS2 was 5.3 and 35.6 times than that of by pure FeOCl and WS2, respectively. The removal rates of AO-II by the F1W2 composite catalysts can reach 93.4 %. The introduction of WS2 contributed to the dissolution of the F1W2 composite, which increased the Fenton reaction. The OH and h+ acted as primary radicals, and O2– and e− acted as the secondary radicals for AO-II degradation by the radical trapping experiment. A synergistic mechanism for FeOCl/WS2 was proposed for the increased AO-II degradation.