Removal Of Cephalosporin Antibiotics In Wastewater By SBBR Process Strengthened By Ce-PbO₂/C Electrode

At present,many of the world's aquatic environment have detected antibiotic residues and resistance genes,and these emerging pollutants pose a serious threat for human health.In this study,the Ce-PbO2/C electrode was first applied to the SBBR process to form a BES(Bioelectrochemical System)system.The removal of cephalosporins and the microbial community were studied.The conclusions are presented as follows:1.The surface of Ce-Pb02/C electrode is firm.After 18 months of aeration and hydraulic erosion,the coating did not fall off,the working condition was steady and well,which proves that the electrode can provide a good environment for microbial growth.The microbial attachment time was shorter than the graphite electrode.2.The optimal conditions of BES system for degradating ceftazidime:pH of 7.0,organic load of 1200 mg·-L-1,voltage of 2.0 V in BES.The removal efficiency after 12 h of ceftazidime by BES system was 100%in the summer and 87.7%in winter,and rised to 94%after 16 h in winter.Both of the BES and SBBR system had a COD removal rate of more than 95%,and the removal efficiency of total nitrogen was between 50%and 80%,but the removal rate of BES was lower than that of SBBR.3.The degradation law of ceftazidime under the optimal conditions of BES system is that the degradation rate can reach to more than 50%within 1 h,and then meet the first order reaction kinetics.In the degradation process,C-N is easy to break,and then ?-lactam ring fractured,and gradually decomposed into small molecules like H20 and inorganic nitrogen.4.The abundance sequence of bacteria was SBBR>BES>electrode.The dominant bacteria in BES under optimized condition was Actinobacteria and Cyanobacteria,accounting for 60%and 30%respectively.The species adhered onto the electrode were similar to that of BES.The abundance of fungi was electrode>SBBR>BES,the electrode plate is rich in an Unidentified fungus,Sordariomycetes,Eurotiomycetes,etc.,which indicating that the electrode can provide excellent survival conditions for the fungus.5.A SPE-HPLC method for the detection of eight cephalosporins and two intermediates simultaneously was established,and 10 antibiotics were separated completely within 15 minutes.The detection limit was 0.448?4.321?g·L-1.The degradation efficiency and rate of cephalosporins by BES after 12h were faster than SBBR system:The degradation rate of BES was 74.20%?94.58%and the SBBR degradation rate was 21.69%?87.53%.The QSPR analysis of seven kinds of cephalosporins in the BES system was carried out.It was found that the first order kinetic k1 was linearly related to LogP(oil and water partition coefficient),?(molecular polarizability)and R(refractive index).The QSPR regression equation was obtained:k1 =-0.046 +0.072 LogP-0.012a + 0.001R,R2 was 0.997,F was 177.575,significance index P was 0.006.