Preparation of 1 T-WS2 under different conditions and its enhancement of Fe(III)/Fe (II) cycle, synergistic catalysis of PMS activation and degradation of organic pollutants

Abstract

In the Fenton-like system, the activation of sulfate-based AOPs (advanced oxidation processes) is inhibited by the slow conversion of Fe(III) to Fe(II). WS2 and other transition metal sulfides has good reducibility and can promote the conversion of Fe(III) to Fe(II), thus having excellent co-catalytic effect. However, the degradation effects of WS2 in different crystal phases are also different. In this paper, WS2 with different 1 T phase content was prepared under different conditions. The co-catalytic performance of WS2 in the WS2/Fe3+/PMS (peroxymonosulfate) system was further studied. When WCl6/TAA = 1: 12 and the temperature was 200 °C, WS2 had the best co-catalytic effect. 1 T phase WS2 was verified by XRD, Raman and TEM. XPS showed that the content of 1 T phase was the highest in W-200. The WS2/Fe3+/PMS system could efficiently degrade 20 mg/L phenol solution within 20 min. Free radical capture experiments and ESR showed that·SO4-,·OH,·O2- were the main active radicals. The excellent reusability of the 1 T-WS2 was proved by recycling experiments and the generation of sulfur vacancies. The system can be widely applied to the degradation of RhB, OFX and other pollutants. The degradation of different pollutants by WS2 in different oxidation systems was studied.