Process-assisted Synergistic Advanced Oxidation Technology For Degradation Of Emerging Antibiotic Pollutant

Such emerging pollutants have gradually brought environmental and health threats,the consumption of antibiotics will not reduce due to substantial dependence on such products and continuous employment in modern medicine.It is impossible to stop the use of antibiotics at the source,and the pollution for the environment will persist for a long time.Advanced oxidation processes（AOPs）have attracted extensive interests in the treatment of refractory toxic pollutants.Commonly,AOPs rely on the generation of strong oxidants,which can eliminate various emerging toxic organic compounds in aquatic environment benefiting from high oxidizing capability of reactive species,exhibiting the features of environmental protection,high safety,wide use,simple reaction equipment and easy industrialization.However,AOPs face the issues of low current efficiency and high operating cost.The paper starts from three directions including degradation process optimization,persulfate activation and electrocatalytic coupling process to improve the degradation efficiency.（1）Ti based BDD anode was prepared by hot wire chemical vapor deposition.The electrocatalytic degradation and kinetic behavior of TMP on the BDD anode were studied,and the influence rules of applied current density,solution pH,TMP concentration,supporting electrolyte type and concentration on the degradation kinetics were analyzed.According to the degradation rate,the optimal reaction conditions for TMP on BDD anode were determined as follows:current density 30m A/cm²,pH=1,TMP concentration 100mg/L,and 0.03 mol/LNa₂SO₄ electrolyte.（2）The traditional single-chamber electrolytic cell faces the problem of limited mass transfer.The three-dimensional carbon felt-based PbO₂anode with filter structure was prepared by simple electrodeposition technique,and the effects of deposition current and time on PbO₂ deposition were analyzed.The three-dimensional structure can not only provide large specific surface area and multi-dimensional electron transfer for electrocatalytic degradation of organic compounds,but also the filter circulation electrochemical reactor can promote the mass transfer performance of the electrocatalytic process to a certain extent and increase the kinetic reaction rate of the degradation process.Under the current density of I=2m A/cm² and pH=5 solution,98%removal of NOR could be realized on the reactor within 1.5 h,showing an excellent electrocatalytic reaction rate.（3）Nano-sized CoFe₂O₄ particles were prepared by hydrothermal method to determine the reaction ratio parameters as catalysts for activated persulfate system.The CoFe₂O₄/PMS concentration of 1mmol/L was obtained by CoFe₂O₄/PMS.When100mg/LCoFe₂O₄NPs was added,the degradation rate of SMX reached 98.63%after60min reaction under neutral condition,and the degradation process was in accordance with the pseudo-first-order kinetic equation.The^·OH and SO₄^·-are the main free radicals involved in the degradation of persulfate by radical quenching experiments.（4）Electrochemical advanced oxidation technology coupling with cathode activation PMS promotes electrocatalytic degradation kinetics.CoFe₂O₄ nanosheets on nickel foam were hydrothermal prepared as cathode materials for electrochemical activation of PMS,which proved that the PMS-CoFe₂O₄/Ni electrochemical system has better catalytic effect.The synergistic mechanism and electrochemical reaction mechanism of the combined system of electrochemistry and persulfate were revealed.The SO₄^·-generated from the CoFe₂O₄ cathode activated by PMS and the^·OH and SO₄^·-generated from the anode acted on the removal of MNZ together,and the optimal operating conditions were determined.The concentration of PMS was 1mmol/L with50mmol/L NaClO₄ as electrolyte,and the degradation rate of MNZ reached 98%after90 min reaction at neutral pH.The above four chapters start with the degradation kinetics,mass transfer limitation and cathode activation of advanced oxidation technology.As a simulated waste water source,the possible attack locations of reactive free radicals are predicted by DFT calculation,and the degradation paths of four representative antibiotics TMP,NOR,SMX and MNZ in different systems are proposed respectively.