The Reinforcement Of Electro-fenton And Electro-peroxone Technology By Activated Sludge Derived Biochar

Dimethyl phthalate（DMP）is an endocrine disruptor,a common plastic additive,widely distributed in natural water,soil,and even the atmosphere,causing harm to organisms at a very low threshold.It is difficult to remove it completely by the traditional wastewater biochemical treatment methods.Therefore,it is necessary to seek more efficient and low-cost methods to deal with the pollution of endocrine disruptors.Therefore,it is necessary to seek more efficient,low-cost and environmentally friendly new methods to eliminate the pollution of endocrine disruptors.In recent years,emerging technologies combining electrochemistry with advanced oxidation process have been widely reported,such as electro-Fenton and electro-peroxone technologies,which have become the emerging hot technologies in the field of refractory organic wastewater treatment.What they have in common is that H₂O₂ is generated in situ by electrochemical cathode two-electron oxygen reduction reaction（2e^-ORR）,which eliminates the hidden danger of H₂O₂ in the storage and transportation process.However,due to the lack of catalytic activity of conventional commercial carbon-based materials,cathode materials should not only consider the rate of oxygen diffusion and mass transfer on their surface,but also consider the material’s own electrochemical properties to compensate for the low selectivity of the two-electron oxygen reduction reaction（2e^-ORR）on electrode surface.Therefore,it is necessary to design a new cathode material which is better than the general commercial carbon material.Activated sludge,a kind of solid waste,is rich in carbon,which is an ideal raw material for the preparation of biological carbon materials.Base on the core idea of"waste treatment with waste",the topic was extended:activated sludge derived biomass carbon enhanced electro-Fenton and electro-Peroxone technology for degradation of organic pollutants.The specific research work of this paper is as follows:1.Preparation and characterization of nitrogen-doped carbon materials derived from activated sludge.This research prepared a novel nitrogen doped carbon material derived from activated sludge and applied it to the synergistic technology of electrochemistry and advanced oxidation.Through the study found that with the additive of zinc chloride,the impedance of the sludge biomass carbon first increases then decreases（minimum 1.20 ohm）,two electronic oxygen reduction（2e^-ORR）capacity（the production of H₂O₂ is 0.97 m M,1.76 times of the AC）,the current efficiency（30%,1.68 times that of the AC）as electrochemical properties compared to commercial activated carbon（AC）has significantly increased.With the introduction of nitrogen species,Graphitic-N can enhance the electron transfer efficiency,and Pyridinic-N and Pyrrolic-N can act as active sites to catalyze the electrochemical reaction,comprehensively improve the material effect,and thus achieve the purpose of enhancing the performance of electrochemical and advanced oxidation synergistic technology.And the dosage of zinc chloride can regulate the ratio of biomass carbon to nitrogen species.2.Degradation of toxic organic pollutants by activated sludge derived nitrogen-doped carbon materials enhanced electro-Fenton technology.In this chapter,the optimal implementation conditions of activated sludge derived biomass carbon materials used as cathode to promote electro-Fenton system degradation of DMP and the degradation effect in real water environment were studied,and the possible reasons affecting the reaction efficiency in water quality were analyzed.Determine the active sludge derived biomass carbon material as a cathode promote electric Fenton system degradation of DMP best adding amount of0.5 m M Fe^2-.In the experiment of simulated degradation of DMP,S4 material has the best performance.In 20 min,S4 as cathode material of DMP degradation rate reached98%,and the first order reaction kinetics constants fitting result for 0.203 min^-1,is1.13 times of that of AC.Activated sludge derived biomass carbon materials as cathode to promote the electro-Fenton system degradation of DMP active species were investigated.It was proved that the main degradation pathway was the·OH radical reaction pathway.Under the background of real water environment,the effect of activated sludge derived biomass carbon material as cathode to promote the electro-Fenton system degradation of DMP was studied.It was found that it was suitable for the treatment of surface water,but not for weakly alkaline groundwater.3.Degradation of toxic organic pollutants by activated sludge derived nitrogen-doped carbon materials enhanced electro-Peroxone technology.In this chapter,the optimal implementation conditions of activated sludge derived biomass carbon materials used as cathode to promote the degradation of DMP by electroperoxone system and the degradation effect in real water environment were studied,and the possible reasons affecting the reaction efficiency in water quality were analyzed.Determine the active sludge derived biomass carbon material as a cathode promote electric Peroxone system degradation of DMP best ozone concentration of 16 mg/L,in the condition of simulating experiment DMP,S4material has the best performance,within 30 min,S4 as cathode material can make0.25 m M DMP degradation completely,and the first order reaction kinetics constants fitting result for 0.1866 min^-1,is 1.7 times of that of AC.Activated sludge derived biomass carbon materials as cathode to promote the degradation of DMP electroperoxone system active species,it is proved that the degradation of the main way is·OH radical reaction path,and a small amount of·O₂^-synergistic reaction.Under the background of real water environment,the effect of activated sludge derived biomass carbon material as cathode to promote the degradation of DMP by electroperoxone system was studied,and it was found that it was suitable for the treatment of groundwater,but not for the treatment of surface water with complex composition.