Catalytic Degradation Of Dye Wastewater By Micro-sized Zero-valent Iron And MOFs-derived Porous Carbon Containing Bimetals In Heterogeneous E-fenton System

Global water scarcity is a major obstacle to human progress and sustainable development goals.Industrial processes generate large volumes of wastewater of complex nature that require proper treatment to reduce or eliminate pollutants in order to be utilized in industrial processes and promote sustainability.Among them,the textile industry is one of the important sources of pollution.Advanced oxidation processes（AOPs）have received much attention from many researchers due to their many advantages,and the newly developed electrochemical advanced oxidation processes（EAOPs）are one of the main alternatives to AOPs and are widely used in various wastewater treatments.Compared with the homogeneous electro-Fenton method,the heterogeneous Electro-Fenton method with solid catalyst-modified electrodes has received a lot of attention,which can recover metal ions,thus greatly reducing sludge production,and can be used in a wide p H range.In this work,the catalytic degradation of dye wastewater by micro-sized zero-valent iron（m ZVI）and bimetallic MOFs-derived porous carbon materials in a heterogeneous Electro-Fenton system was investigated and improvements were made in the system and/or material synthesis,respectively.The micro-sized zero-valent iron non-homogeneous system was investigated for the degradation of real textile wastewater as system I,using magnetically immobilized micro-sized zero-valent iron with Ti/Ru O₂-Ir O₂ sheets to form a composite anode.The effects of different process parameters such as m ZVI dosage,H₂O₂ concentration,applied voltage and p H on the removal rate of the actual textile wastewater were evaluated and the optimal parameters were verified by Tafel curves and Nyquist plots of the electrochemical workstation.The optimum operating conditions for the wastewater treatment were:H₂O₂ dosage of 0.10 mol/L,applied voltage of 5.0 V,m ZVI dosage of 1.0 g/L,and initial p H of 3.0.The removal rates of TOC and COD reached 92.44%and 82.84%,respectively,within 60 min.GC-MS was used to analyze the pollutants before and after degradation and to propose a suitable reaction mechanism.The bimetallic MOFs-derived porous carbon non-homogeneous electro-Fenton system was used as system II,and the new MIL-53（Fe）and Fe Mo bimetallic MOFs were synthesized from divalent iron salts,and the porous carbon materials with Fe Mo bimetallic MOFs as precursors were obtained by high temperature carbonization.The effects of different process parameters such as catalyst dosage,applied current,p H value,pollutant concentration and electrolyte on the pollutant removal rate in this system were investigated.The best removal effect（96.5%）was achieved with the cationic dye rhodamine B as the target pollutant at catalyst dosage of 0.2 g/L,constant current of 100 m A,p H of 5.87 and electrolyte concentration of 50 m M Na₂SO₄.The Nyquist plots of the electrochemical workstation were used to evaluate the electron transfer kinetics on the surface of the different catalysts.XRD,XPS and SEM-EDS,BET tests were used to analyze the performance of the different solid catalyst materials synthesized.The possible reaction mechanism of the system was also effectively proposed in combination with free radical burst experiments and EPR tests.