Construction And Performance Of A Filtered Heterogeneous Electro-Fenton Reactor

With the development of human industry,large quantities of non-degradable,highly toxic and complex organic wastewater are entering the environment,which has a serious impact on natural water bodies and threatens clean water resources.As water pollution becoming increasingly serious,researchers have developed a variety of technologies to effectively control the environmental impact of organic waste.Electro-Fenton technology is gaining increasing interest due to its advantages such as in-situ hydrogen peroxide generation,environmental friendliness,no need for additional reagents,mild reaction conditions and easy process control.The cathode material not only determines the efficiency of H₂O₂ production,but also affects the suitability and stability of the cathode,and is also important for reducing the cost of wastewater treatment.Therefore,the development of high-performance cathode materials is of great importance for the development and application of electro-Fenton technology.In addition,the structure of the reactor affects the mass transfer efficiency and current efficiency,while high mass transfer efficiency and current efficiency will greatly improve the performance of the reactor.Therefore,the development of practical and high-performance reactors is of great significance to achieve the widespread application of electro-Fenton technology.In this study,a graphite felt（GF）loaded carbon black-polytetrafluoroethylene（CB-PTFE）cathode（CGF）prepared by bonding and calcination using acidified GF as a substrate.It has the advantages of good performance,stable structure and high applicability.The surface morphology,hydrophilicity,functional group species,elemental species and electrochemical properties of CGF were investigated.The optimum preparation conditions were searched for,the effect of different operating conditions on its pollutant removal performance was investigated and the stability of CGF was examined.Titanium film（TM）loaded SnO₂-Sb anodes（PTM）are prepared by impregnation and calcination using a titanium film as a substrate.The CGF,PTM and Al/Fe solid catalysts（Al/Fe）were combined to design and construct the reactor.Examining the surface properties of PTM and Al/Fe and testing the electrochemical properties of PTM.To investigate the effect of different operating conditions on reactor performance and to examine its bisphenol A（BPA）removal performance,repeatability,suitability and contaminant treatment mechanisms.The following research results were obtained.（1）Characterization of the CGF showed that CB-PTFE was successfully loaded onto the GF substrate and that the distribution was homogeneous without damaging the original structure of the GF.The hydrophobicity of the electrode has improved.High temperature calcination and load CB make CGF carbon structures more ordered and changed GF’s functional group type.The CGF prepared under optimum conditions exhibited good electrochemical properties.The effects of voltage（U）,pH and aeration（V）on the performance of the electrodes were examined.The best electrode performance was found at operating conditions of U=-1.2 V,pH=3 and V=0.2 L/min.Under these conditions,the hydrogen peroxide yield was 20.07 mg/h cm³ and the BPA removal rate was 96.46%.The CGF has proven to be stable in continuous tests.（2）The electrochemical membrane reactor is constructed with CGF as the cathode,PTM as the anode and Al/Fe as the solid phase catalyst.It is capable of coupling electro-Fenton and anodic oxidation.And it has the advantages of high mass transfer efficiency,low iron precipitation and continuous operation.The effects of flow regime,voltage（U）,pH,electrolyte concentration（C）and treatment fluid flow rate（I）on reactor performance were investigated.It was found that when in Flow-through mode,the treatment fluid flows through the CGF and PTM in sequence,the treatment effect is better than in Batch mode.When U=2.5 V,I=1mL/min,pH=3,C=0.05 mol/L,V=0.2 L/min,the reactor has the best performance.100 ml10 mg/L BPA simulation wastewater was run 240 min in the reactor,and the BPA removal rate was 99.19%.Successive tests have demonstrated the good reusability of the reactor and the low iron precipitation of Al/Fe.The reactor is also effective for higher concentrations of BPA solutions.In addition,the reactor achieved 82.81%,99.82%and 99.75%removal of phenol（Phenol）,sulfamethoxazole（SMX）and rhodamine B（Rh B）respectively under the above conditions.The experimental results show that the reactor has good applicability.Oxidation mechanism tests show that the electro-Fenton process plays a dominant role in the degradation of pollutants,with·OH andO₂^-·being the main oxidation groups.