Study On Degradation Of Ofloxacin Wastewater Using Dielectric Barrier Discharge Non-thermal Plasma Technology

The problem of bacterial resistance caused by the extensively use of antibiotics has attracted widespread public attention and poses a major threat to public health and the global environment.Ofloxacin(OFX)is a synthetic third-generation quinolone antibiotic that enters the aquatic environment through wastewater discharge,ofloxacin and its metabolites accumulate in the aquatic environment.Ofloxacin burden in water may be directly toxic to organisms,even at low concentrations ofloxacin may be enriched in organisms through the food chain.Common antibiotic treatment methods do not completely decompose the residual antibiotics in water,so efficient removal of ofloxacin from wastewater has become an essential task of water pollution prevention and control.As an advanced oxidation technology,Dielectric Barrier Discharge(DBD)non-thermal plasma technology possesses the superiority of rapid removal of organic contaminants.In order to make full use of the ultraviolet light generated in DBD process to improve the degradation effect of target pollutants,iron and graphene co-doped titanium dioxide(TiO2)catalytic ceramic plate was prepared.The combining degradation of ofloxacin was carried out by non-thermal plasma and Fe-rGO-TiO2.Graphene and iron have excellent ability to transfer electrons to produce holes and generate doping effect,which can significantly improve the photocatalytic performance of TiO2.In this thesis,the feasibility of DBD non-thermal plasma combined with Fe-rGO-TiO2 catalyst to degrade ofloxacin wastewater was investigated.Through XRD,FTIR,SEM,and BET characterization analysis,the results show that Fe3+ and graphene are successfully doped in TiO2,which can refine TiO2 grains,increase the specific surface area,and improve the catalytic performance of TiO2 In the oxidative degradation experiment,the Fe-rGO-TiO2-DBD synergistic system showed the best removal effect.The degradation rate of ofloxacin reached 86.37%after 60 min reaction,and the energy yield was improved at the same time.The thesis explored the effect of initial operating conditions on the degradation effect of ofloxacin.The results showed that the degradation effect of ofloxacin increased with the decrease of initial concentration and conductivity;increasing the input power promoted the degradation effect,but the corresponding energy yield decreased;the synergistic system is more suitable for operation in neutral conditions.Metal ions,sodium percarbonate and humic acid have catalytic effects and can improve the degradation efficiency of ofloxacin.The results of active radical trapping experiments and hydrogen peroxide and ozone measurements proved that hydroxyl radicals,superoxide radicals,hydrogen peroxide and ozone were important active substances involved in oxidative degradation reactions.Mass spectrometry was used to analyze the intermediate products of ofloxacin in the synergistic system.It was speculated that the degradation and transformation mechanism of ofloxacin included decarboxylation,piperazinyl dealkylation and ring cleavage reactions.