Enhancing The Efficiency Of FeOCl Catalytic Degradation Of Organic Matter By Complexation Method And Revealing Its Mechanism

Compared with the traditional microbial treatment,adsorption method and Fenton method of water pollution,Fenton-like advanced oxidation process has the advantages of high degradation efficiency,simple infrastructure,low cost,low technical requirements and minor secondary pollution.The heterogeneous Fenton catalysts based on iron oxide chloride（FeOCl）or based on it as the precursor have been widely paid attention due to their high catalytic activity,easy availability of raw materials,mild action conditions and easy separation and recovery.However,because the highly active Fe²⁺in the catalyst will be converted to the low-active Fe³⁺in the reaction process and is difficult to regenerate,the catalytic activity of FeOCl is inhibited,which hinders the promotion and application of this method.According to the above problems,in this paper,tungsten disulfide（WS₂）and iron oxide/carbon nano tubes（Fe₂O₃/CNTs）were used to enhance the catalytic activity of FeOCl in Fenton-like reactions,and the mechanism was discussed.In order to solve the problem that Fe³⁺is difficult to be reduced to Fe²⁺in the Fenton reaction,WS₂ composite method was used to enhance FeOCl activation hydrogen peroxide to degrade phenol and the reaction mechanism was studied.The results showed that it had significant degradation effect under the condition of p H from 3 to 9,and the degradation of phenol（1 mmol/L）reached99.2%in 5 minutes（The concentration of H₂O₂ is 6 m M and the concentration of FeOCl@WS₂ is 0.4 g/L）.In addition,the composite has higher mineralization rate than FeOCl,mild action conditions,with a salinity resistance up to 10m M,and has a certain cycle stability.The hydroxyl radical and singlet oxygen radical play the main role in the reaction by free radical quenching experiment.In order to ensure the regeneration effect of Fe²⁺in the Fenton-like reaction,improve the recoverability of the catalyst and avoid the se condary pollution caused by the introduction of sulfide,FeOCl was modified by magnetic Fe ₂O₃and electron-rich CNTs,and the mechanism of its action in the catalytic reaction was discussed.The experimental results show that FeOCl/Fe ₂O₃/CNTs not only has excellent catalytic performance,but also can completely remove MB within20 minutes,at a low H₂O₂ concentration of 0.8 millimole,in a dosage of 0.2 g/L,and also shows good reactivity in a wide p H from 3 to 7.Finally,FeOCl/Fe₂O₃/CNTs coated laminated films were prepared for continuous flow degradation of methylene blue,which still achieved good degradation effect.XPS analysis showed that the addition of CNTs formed a new C-O bond,which promoted charge transfer in the Fe³⁺/Fe²⁺redox cycle,thus enhancing the activity of the catalyst.Therefore,the addition of electron-rich materials such as carbon nanotubes is an effective strategy to improve the performance of Fenton-like catalyst.To sum up,in this study,FeOCl was combined with WS₂ or Fe₂O₃/CNTs to improve its catalytic activity in Fenton-like reactions,and the paper report s the mechanism of Fe²⁺regeneration promoted in two ways,and provides two new ideas to solve the limitation of catalytic activity of Fe OC l in advanced oxidation.It provides a reference for the study of high efficiency iron catalyst in Fenton-like reaction.