Research And Development Of A Novel Type Of Electro-Fenton Cathode And Its Treatment Of Coking Wastewater

The treatment of refractory organic wastewater is a major problem in the field of wastewater treatment,and the traditional wastewater treatment process is difficult to meet its emission requirements.Electro-Fenton technology has attracted much attention because of its strong oxidizing hydroxyl radical,which can effectively treat refractory organic wastewater.In this research,the Fe/AC/Ni cathode was used to construct electro-Fenton reaction system.The key indicators of its application in engineering application were the electrode area load and reactor volume load,and the parameters and conditions of coking wastewater treatment were explored.The empirical formula for guiding the treatment of coking wastewater.On this basis,in order to further optimize the performance of the electro-Fenton cathode,this study improved the Fe/AC/Ni cathode to prepare the electro-Fenton air diffusion cathode(air-Fe/AC/Ti).The electro-Fenton system constructed by air-Fe/AC/Ti cathode was used to treat coking wastewater,and the reaction conditions were optimized to verify the cathode performance.In the processing research of Fe/AC/Ni cathode,the effects of electrode effective surface area,wastewater influent COD concentration and treatment time on COD removal rate were studied by single-factor experiments.On this basis,the response surface model of cathode application was established to obtain the empirical equation of Fe/AC/Ni cathode for coking wastewater treatment and the optimal conditions for cathode application.The optimum application conditions of Fe/AC/Ni cathode were as follows:electrode effective surface area was 28.5 cm²,wastewater influent COD concentration was 1.76 kg·m^-3,and the treatment time was 160.43 min.Under these conditions,different coking wastewaters were used to prepare reaction wastewater.The COD removal rate can be predicted by the empirical equation to be 96.39%.The actual experiment showed that the maximum COD removal rate was 98.51%,and the maximum relative error is 2.12%.Under these conditions,the electrode area load was9.24 g·cm^-2·h^-1,and the reactor volume load was 0.66 kg·m^-3·h^-1.In air-Fe/AC/Ti cathode research and development,air-Fe/AC/Ti cathode was prepared by improving the Fe/AC/Ni cathode by increasing the air diffusion layer,optimizing the type of load metal salt,optimizing the load amount,and replacing the diversion metal skeleton.The performance of the cathode was characterized by the degradation efficiency of methyl orange.The best preparation method and conditions of the electrode were determined.The electrode materials were characterized by SEM-EDS and XRD to confirm the load effect.The results show that the optimal loading metal salt is ferric nitrate,the optimal loading amount is 0.7%,the optimal calcination temperature of the material is 350°C,and the optimal ratio of conductive agent to binder in air diffusion layer is:1:2.The performance of air-Fe/AC/Ti cathode is significantly better than that of the original Fe/AC/Ni cathode.The oxide of iron was loaded well in the catalyst layer and still existed effectively in the cathode material after the reaction.In the research on the treatment of coking wastewater by air-Fe/AC/Ti cathode,the effects of applied current,electrode spacing,initial p H value of wastewater,and reaction time on the COD removal rate of coking wastewater were studied by single-factor experiments.The optimal conditions for the treatment of coking wastewater by the electrode were studied by response surface optimization.Finally,the water samples before and after the reaction were characterized by Ultraviolet-visible spectroscopy,Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry to analyze the electro-Fenton reaction mechanism.The results show that the optimal treatment conditions of coking wastewater are as follows:the applied current is 2.31 A,the electrode spacing is 1.47 cm,the initial p H value of water sample is 7,and the reaction time is 140 min.Under this condition,the optimal COD removal rate is 98.03%.Air-Fe/AC/Ti cathode had obvious degradation effect on organic pollutants in coking wastewater,and the COD degradation conformed to the pseudo-first-order degradation kinetics.The research can provide a reliable empirical formula for the treatment of coking wastewater by Fe/AC/Ni cathode,which has good industrial application.At the same time,the improved electro-Fenton cathode has better performance and wider application range.