| In recent years,the overuse and misuse of antibiotics have received much public attention,among which fluoroquinolone antibiotics represented by ofloxacin（OFX）have limited the traditional biological treatment process due to their inhibitory effect on microorganisms.Advanced oxidation technology based on persulfate has broad prospects in the field of treatment of refractory organic wastewater.At present,more and more new nano-catalysts（such as metal-organic framework,metal oxide,nano-carbon,etc.）have been used in the activation of persulfate.However,most catalysts are in powder form,which has problems such as poor stability and difficult recovery after treatment,and the mass transfer and activation efficiency are not high when the persulfate is activated with traditional Batch or two-dimensional plate electrode.Activated carbon fiber felt（ACF）,as an excellent carrier material,has a large specific surface area and unique three-dimensional pore structure,which can be used in activated persulfate system.In addition,in order to improve the efficiency of mass transfer,the contact between the target pollutant and the oxidant can be achieved by constructing the overflow reaction device.This paper mainly includes the following research contents:（1）Oxidative degradation of OFX in E+ACF+PMS system with modified activated carbon fiber felt electrode.The modified ACF can degrade OFX more significantly in Flow through mode than in Batch mode and the Flow through mode can improve the mass transfer efficiency during the reaction process and realize the rapid and efficient degradation of OFX.Compared with ACF adsorption system,PMS oxidation system and electrolytic system,the removal rate of OFX and pseudo-first-order kinetic reaction rate constant of E+ACF+PMS system were significantly increased,and the coupling effect of electric activation and activated carbon fiber activation was obviously produced.By optimizing PMS concentration,voltage,initial p H,residence time and other conditions,the degradation rate of OFX under optimal conditions is about 83%.Common inorganic anions such as PO43-,HCO3-and Cl-in wastewater have a certain impact on the degradation of OFX in this system:among them,Cl-has a certain promoting effect on the degradation of OFX,and PO43-,and HCO3-inhibit the degradation of OFX.The experimental analysis of free radical capture shows that the degradation of OFX by the system has both free radical and non-radical effects.In addition,activated carbon fiber still shows good stability after 30 times,which indicates that the E+ACF+PMS system can effectively protect the activity of ACF and extend its service life.（2）Study on the properties and mechanism of oxidative degradation of OFX by ACF@Mo S2@Co overflow activated permonosulfate.The Mo S2@Co composite was synthesized on the activated carbon fiber substrate by hydrothermal method and impregnation calcination method.The composite was closely attached to the surface of ACF,which overcame the difficulty of powder catalyst recovery in the process of material synthesis.The surface exposed rich active sites of Mo and Co,which effectively increased the activation efficiency of PMS.The prepared ACF@Mo S2@Co catalyst was applied to the activated persulfate system to investigate its OFX degradation effect.The results showed that the Flow through mode was faster and more efficient than the Batch mode in the catalytic degradation of OFX.The optimal treatment conditions of 10 mg·L-1ofloxacin wastewater were p H=5,[PMS]=1.5 mmol·L-1,residence time is 26.50 s,and the removal effect of OFX was better.The results of mechanism exploration showed that the free radicals involved in the system included·OH,·SO4-,1O2and·O2-,and the degradation of OFX was completed under the combined action of free radicals and non-free radicals,in which sulfate radical reaction was the main reaction.The ACF substrate with strong adsorption performance was modified,and the Flow through mode based experimental device was constructed for the degradation of organic pollutants.The prepared catalytic materials showed excellent degradation performance,and provided a green and environmentally significant method for the treatment of fluoroquinolone antibiotics which are difficult to biodegrade,which is of great significance for environmental protection and material utilization. |
