| Antibiotic is a kind of common antibacterial drugs which has been widely used in medical treatment,animal husbandry and aquaculture industry.To meet the market demand for antibiotics,the industrial production is increasing gradually.And due to the large number of production and use of antibiotic,the treatment of antibiotics wastewater with high concentration has become a hot focus and difficult issue.Therefore,it is significance to explore the effective degradation methods for antibiotics wastewater.In this study,a new kind of iron-carbon material was firstly prepared by using reducing iron powder and activated carbon powder as raw material with the addition of a certain amount of additive through high temperature calcination method.And then the effects of iron-carbon mass ratio,iron-carbon content(of the total mass)and calcination temperature on the treatment efficiency of sulfamerazine antibiotics wastewater(named as SM1)by micro-electrolysis method was investigated.According to the experiment results,the optimal preparation conditions were determined with the iron-carbon mass ratio,iron-carbon content and the calcination temperature of 1:1,80% and 900 oC,respectively.In addition,the new composite was found as a porous material with big specific surface area and narrow aperture by scanning electron microscope(SEM)and BET specific surface area test,which was conducive to the removal of antibiotics.In the actual projects,the most common material used in micro-electrolysis is the mixture of scrap iron and activated carbon.Therefore,a certain concentration of amoxicillin(AMX),ampicillin(AMP)and penicillin G sodium(PG)solution as the synthetic wastewater wasprepared and treated through micro-electrolysis method with this traditional material,the mixture of iron powder-active carbon powder.Firstly,the influence of reaction time,initial pH,iron-carbon mass ratio and aeration condition on the removal efficiency of three kinds of penicillins with this material was studied.Secondly,the reaction process of iron-carbon micro-electrolysis was explored through the contrast test,which could be a complex process mainly consisting of electrochemical reaction,oxidation-reduction,coagulation and adsorption.In this reaction,the coagulation caused by Fe3+ contributed to a nearly 21.8% effect.Finally,at the above optimum conditions,the micro-electrolysis experiments with iron powder-active carbon powder and the new iron-carbon composite material were conducted,respectively.The new iron-carbon composite was found to have a better performance on penicillin removal compared with the iron powder-activated carbon powder.In order to value the application of new iron-carbon composite in the antibiotics wastewater treatment by micro-electrolysis method,a certain concentration of sulfamerazine(SM1),sulfamethoxazole(SMX)and sulfamethoxydiazine(SMT)solution was prepared as the synthetic wastewater,respectively.The optimal conditions were obtained based on the single factor experiment with the initial pH,iron-carbon loading and reaction temperature of 2,1g/mL and 25 oC.And after 8 hours of reaction time at these conditions,83.0%,65.8% and 75.6% removal efficiencies of SM1,SMX and SMT were observed,respectively.Furthermore,the degradation mechanism of sulfonamide antibiotics by iron-carbon micro-electrolysis was discussed according to the concentration variations of SM1,TOC,TN,NO3-,SO42-,Fe2+and Fe3+from the effluent and product analysis by liquid chromatography/mass spectrum(LC/MS)method.One of the main reaction pathways could be that,the S and N atoms were released from the S-N bond cleavage and then removed by further redox reactions.In conclusion,the new iron-carbon composite material has good physical properties and its porous structure is more suitable for the treatment of antibiotic wastewater compared to the traditional material of iron powder-carbon powder.In addition,the iron-carbon micro-electrolysistechnology is proven to be an economic,practical and effective pretreatment method for antibiotic wastewater. |
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