Study On Dielectric Barrier Discharge Combined With Catalytic Materials For Removal Of Antibiotics In Wastewater

Due to the abuse and improper handling of antibiotics,more and more antibiotics were detected in the environment,which poses a huge threat to the ecological environment and human health.Traditional methods,such as adsorption,membrane separation and activated sludge method,usually had the problems of low removal efficiency and secondary pollution.Therefore,it is urgent to develop an efficient antibiotic treatment technology.As one of the advanced oxidation processes（AOPs）,dielectric barrier discharge plasma（DBD）had received more and more attention due to its non-selective and high efficiency.However,DBD also had some defects such as low energy utilization.In view of these problems,introducing catalytic materials into DBD system to construct DBD catalytic system could effectively solve the problem of low energy utilization.Therefore,DBD synergetic catalytic material technology was used to degrade antibiotic wastewater in this study.In this paper,different crystal forms MnO₂and different Fe/Mn molar ratios of activated carbon-supported iron-manganese oxide（FMAC）catalytic materials were prepared by hydrothermal synthesis,and ciprofloxacin（CIP）and tetracycline hydrochloride（TCH）wastewater were degraded respectively.The effectiveness of the DBD synergistic system in degrading antibiotic wastewater was investigated.The effect of single influencing factor on the degradation of antibiotic wastewater was analyzed.And the main mechanism of the DBD synergistic catalytic system to degrade antibiotic wastewater was analyzed.The degradation effect of CIP wastewater by DBD and MnO₂ catalytic system was studied.Three crystal forms MnO₂（α-MnO₂,β-MnO₂ andγ-MnO₂）were prepared by hydrothermal method.XRD,SEM and XPS were used to characterize MnO₂ with different crystal forms.The experimental results of CIP degradation in different reaction systems showed that the synergetic catalytic system effectively promoted the degradation efficiency of CIP,among whichα-MnO₂>γ-MnO₂>β-MnO₂,DBD synergeticα-MnO₂ had the best degradation effect,and the CIP degradation efficiency was up to 93.97%after 50 min.The lower initial concentration and higher discharge voltage promoted the degradation of CIP,and the degradation efficiency of CIP first increased and then decreased with the increase of air flow,CIP had the best degradation effect under the neutral conditions.The addition of tert butyl alcohol（TBA）and p-benzoquinone（p-BQ）significantly reduced the degradation efficiency of CIP,which proved that·OH and·O₂^-play a dominant role in the degradation of CIP.The concentration of O₃ in the liquid phase increased with the increase of treatment time.The addition ofα-MnO₂ catalyst promoted the formation of more·OH in the DBD system.Through LC-MS analysis and identification,nine intermediate products were identified and three possible degradation pathways were inferred.The degradation of TCH wastewater by DBD combined with FMAC catalytic system was studied.FMAC with different molar ratio of Fe/Mn were prepared by hydrothermal method;The prepared FMAC materials with different Fe/Mn molar ratio were characterized by XRD,TEM and XPS.The experimental results of different reaction systems showed that the synergetic catalytic system could effectively promote the removal of TCH,among which FM<F3M1AC<F1M2AC<F1M1AC<F2M1AC,and DBD combined with F2M1AC had the best effect on the degradation of TCH.With the increase of discharge voltage and catalyst dosage,the degradation efficiency of TCH was continuously increased,and the degradation effect of TCH was the best under alkaline conditions.The addition of dimethyl sulfoxide（DMSO）significantly inhibited the degradation of TCH,indicating that·OH plays a leading role in the degradation of TCH.And the formation of O₃ in the liquid phase increased with the increase of the discharge reaction time.The introduction of F2M1AC material promoted the formation of more·OH.Through the results of LC-MS,the analysis showed that the oxidative destruction of carbon-carbon double bonds,carbon-nitrogen bonds and benzene ring was the main degradation pathway of TCH.