Construction Of A New Fenton-like System And Its Degradation Of Organic Pollutants In Water

Degradation treatment of azo dye wastewater is a key problem in the field of water pollution control.As a highly concerned advanced oxidation technology,heterogeneous Fenton process can overcome the disadvantage of more iron sludge in the traditional Fenton process,and also achieve the effect of oxidation to remove organic pollution,which has very good prospects for development.Purpose of this research is to explore such Fenton process improvements,design a new kind of Fenton catalysts,and research the degradation mechanism and efficiency of transition metal oxide and its composite material system of heterogeneous activation of hydrogen peroxide,and on this basis,build a new kind of fenton system,iron oxide catalytic and adsorption performance was used to study the adsorption of inorganic arsenic in Fenton system,The removal of organic and inorganic arsenic in a reaction system can be realized simultaneously.The specific contents are mainly as follows:（1）In this paper,Fe-Mnporous microspheres bimetallic catalysts were prepared by hydrothermal template method and coprecipitation method,and showed good catalytic activity to drive H₂O₂ catalytic oxidation of azo dye degradation in heterogeneous Fenton system.Fe-MnO_x was characterized by SEM,XRD and XPS,and the size of the catalyst was about 600-800 nm spherical structure.The degradation efficiency of ARSAⅢ and CPAⅢ in Fe-MnO_x/H₂O₂ system was investigated.Under the conditions of Fe-MnO_x dosage of 1.2 g/L,H₂O₂concentration of 15 mmol/L and initial pH of 3.0,The degradation efficiency of 30 mg/L ARSAⅢ reached 92.5%within 40 min.Under the condition of 15 mmol/L H₂O₂ concentration,the degradation efficiency of 30 mg/L CPAⅢ reached 93.3%within 40 min.The results of quenching test showed that·OH was the main active radical in Fe-MnO_x/H₂O₂ system.XPS analysis showed that Mn³⁺activated H₂O₂,and also promoted the reduction of Fe3+to Fe²⁺,and the presence of Fe²⁺could reduce Mn³⁺to Mn²⁺,thus accelerating the cycle of Fe²⁺/Fe³⁺and Mn²⁺/Mn³⁺/Mn⁴⁺in the system,and synergistic effect improved the activation performance of H₂O₂.The intermediates of ARSAⅢ degradation in Fe-MnO_x/H₂O₂ system were determined by LC-MS,and the possible degradation path of ARSAⅢ was speculated.（2）Iron oxides can be used as catalysts for heterogeneous Fenton reactions and as adsorbents in water.Based on the dual effect of iron oxides,the heterogeneous Fenton system of iron oxides is considered to treat wastewater containing organic arsenic compounds.Three iron oxides FeOOH,Fe₃O₄ and Fe₂O₃ were selected:The results showed that when the initial pH of FeOOH was 5.0,the degradation efficiency of 10 mg/L ROX reached more than 90%in40 min.At the same time,after five cycles of experiments,the catalyst also showed good catalytic activity.The design idea of the experiment was well realized,and the inorganic arsenic in the final effluent was controlled below 40 mg/L.Of the three catalysts,FeOOH had the most stable treatment effect.