Investigating The Transformation Mechanism Of Fe Elements And Efficiency Of Wastewater Treatment In Fe/C-Fenton Process Based On PH Control

The application of Fe/C-Fenton process in the treatment of chemical organic wastewater has always been a hot spot in the field of water treatment.In this study,a typical refractory organic pollutant,benzotriazole（BTA）,was systematically studied by controlling p H and reaction time.The dissolution rule of iron in Fe/C micro-electrolysis reaction was studied.The optimal conditions of Fenton oxidation reaction were investigated by matching the corresponding amount of hydrogen peroxide in the subsequent Fenton oxidation reaction.The morphological transformation of Fe in the process of Fe/C-Fenton reaction was studied.In this paper,the Fe/C-Fenton process based on p H control is studied in depth with the dynamic small-scale experiment.The dissolution rule of ferrous and total iron in the process of Fe/C microelectrolysis was investigated when only the initial p H value and the whole process p H value were controlled.When controlling the whole process p H=2,3,4,with the increase of the reaction time of Fe/C micro-electrolysis,the concentration of ferrous divalent in the solution increases gradually with the total iron concentration,which has a good linear relationship,and the dissolution of ferrous divalent and total iron is higher than that of only controlling the initial p H=2,3 and 4.In the Fenton oxidation process,the optimum ratio of Fe2+to hydrogen peroxide is n(Fe²⁺):n（H₂O₂）=1:2,the optimum reaction time is 120 min,and the optimum p H condition is to control the whole process p H=3.Under the optimum conditions,for BTA wastewater with 10 g/L concentration and COD=14443 mg/L,the removal rate of Fe/C-Fenton process based on p H control reached 96%.In the Fe/C-Fenton process of controlling the whole process p H,iron in the solution mainly exists in the form of ferrous bivalent in the micro-electrolysis reaction of Fe/C.With the increase of reaction time,the concentration of ferrous bivalent increases continuously,and the concentration of ferrous trivalent does not change significantly.In Fenton oxidation reaction,the concentration of ferrous divalent decreases gradually and the concentration of ferrous trivalent increases gradually.The total iron concentration after Fe/C-Fenton reaction is lower than that before the reaction.In dynamic small-scale experiments,Fe/C-Fenton process based on p H control has higher COD removal rate than traditional Fe/C-Fenton process.Through the research results of this paper,the law of iron dissolution in Fe/C micro-electrolysis reaction can be clarified,and the basis of hydrogen peroxide dosage in subsequent Fenton oxidation can be provided.The transformation of Fe in Fe/C-Fenton process based on p H control was analyzed and dynamic small-scale experiments were carried out,which provided a reference for the application of Fe/C-Fenton process in the treatment of chemical organic wastewater.