Study On Carbamazepine Degradation In Wastewater By Dielectric Barrier Discharge Plasma In Collaboration With Fe³⁺/Sulfite

Carbamazepine（CBZ）is a typical drug in pharmaceuticals and personal skincare products（PPCPs）.Its molecular chemical structure is relatively stable,and it is frequently detected in various types of wastewater,posing potential risks to the natural environment and human health.Traditional wastewater treatment methods cannot effectively remove it.Therefore,it is necessary to seek an efficient degradation water treatment technology to degrade CBZ in wastewater.Dielectric barrier discharge plasma technology is a new advanced oxidation water treatment technology,which has the advantages of low selectivity and high speed and can effectively degrade organic pollutants in wastewater.Sulfite can be activated by the action of metal trivalent iron salts or ultraviolet light,producing highly oxidizing oxygen sulfur radicals that act on the degradation of organic compounds in wastewater.In this study,sulfites and ferric salts were added to the dielectric barrier discharge plasma system.The physical and chemical effects of the discharge were used to make ferric ions catalyze sulfites to produce oxygen sulfur free radicals and ferric ions were reduced to divalent iron ions.The divalent iron ions reacted with hydrogen peroxide generated in the system to produce more hydroxyl groups,improving the degradation effect of CBZ.The main research content and conclusions of this article are as follows:（1）A dielectric barrier discharge reaction device was made to investigate the effect of different experimental parameters on the degradation of CBZ in a separate dielectric barrier discharge plasma and to analyze the changes in p H and conductivity of carbamazepine solution as well as the production of ozone and hydrogen peroxide under different discharge voltages.The results show that when the discharge voltage is 21 k V,the air flow rate is 0.8 L/min,liquid circulation flow rate of 0.16 L/min,the volume of degradation solution is 250 m L,the initial concentration of CBZ is 10 mg/L,and the initial p H of the solution is 5,the CBZ degradation effect is the best,reaching 88.95%.The higher the discharge voltage,the greater the conductivity of the solution,the decrease in p H value,and the appearance of acidity.The production of hydrogen peroxide and ozone in the system increases.Under the optimal parameter conditions,the TOC removal rate of CBZ solution is 7.61%,and the energy utilization efficiency is 1247.706 mg/（kw·h）.（2）The degradation effects of CBZ in dielectric barrier discharge alone,sulfite alone,Fe³⁺/sulfite,dielectric barrier discharge/Fe³⁺,dielectric barrier discharge/sulfite,and dielectric barrier discharge co-Fe³⁺/sulfite systems were compared and analyzed.The regression model between the degradation rate of CBZ and the concentration of sulfite,p H,and ferric salt was established by the response surface method.The results show that the CBZ degradation effect is the best in dielectric barrier discharge and Fe³⁺/sulfite systems.The regression model of the CBZ degradation rate was established,and the model had better fitting accuracy and prediction.The model predicted that the optimal conditions for the degradation of CBZ in the collaborative system were as follows:sulfite concentration was 0.102 m M,p H was 3.32,and ferric ion concentration was 1.457 mg/L.Under these conditions,the predicted degradation rate of CBZ was 100%.The predicted value of the model was verified,and the error between the degradation rate of CBZ and the actual one was only 1.9%.The TOC removal rate of the CBZ solution was 17.45%,and the energy utilization efficiency was 1620.989 mg/（kw·h）.（3）EPR radical recognition and radical inhibition experiments in the system of dielectric blocking discharge with Fe³⁺/sulfite cooperation showed that single linear oxygen,hydroxyl,and superoxide radicals generated in this system were involved in the degradation of CBZ.The UV absorption spectra of the degradation process were analyzed.It was found that CBZ was gradually decomposed and the molecular structure was disrupted.Using MULLIKEN theory in Gauss View 6.0 and combined with high-performance liquid chromatography-mass spectrometry（HPLC-MS）analysis,eight intermediates were identified,and it was deduced that the main degradation mechanism of CBZ molecules includes the cleavage of olefin double bonds,aldehyde groups,decarboxylation process,and finally mineralization to water and carbon dioxide.Figure[47]table[13]reference[105]...