Degradation Of Cefotaxime Sodium In Water By Ozone Catalytic Oxidation

At present,with the rapid development of the medical industry,the use of antibiotics is also becoming more widespread,but the antibiotic wastewater is complex in composition,high in organic matter,high in toxicity,and difficult to be biodegraded.The traditional biochemical treatment process is now widely used,the treated water still contains a large amount of refractory organic matter,which causes persistent pollution to the ecological environment.Ozone catalytic oxidation technology is a new advanced oxidation technology based on ozone oxidation.It can not only effectively remove biodegradable organic matter,improve its biodegradability,but also has no secondary pollution during the reaction process.It is being studied and used more and more widely.Cefotaxime sodium,a 3-acetoxymethylcephalosporin,is a third generation,semisynthetic,antibacterial cephalosporin.In this research,CFX wastewater was treated by ozone catalytic oxidation technology and the purpose of degradation is achieved.In this research,Firstly,the toxicology of cefotaxime sodium was analyzed by electrochemical technique.Then the law of ozone absorption and decomposition in water was studied.Finally,the effects of ozone oxidation alone,homogeneous ozone catalytic oxidation and heterogeneous ozone catalytic oxidation on the degradation of CFX wastewater were studied.The degradation mechanism was analyzed by using the changes of OH,degradation products and mineralization of water.The simulated actual wastewater was configured to analyze the change of biodegradability before and after degradation.The experimental results show that the toxicological study indicates the relationship between CFX and base is obtained by cyclic voltammetry(CV)and other methods,which proves that CFX has certain toxicity and finds the strong relationship with the ability of bases: guanine > adenine > cytosine > thymine.Under the influence of different pH,ozone generator current and air flow,the ozone concentration in water is higher than that in alkaline water under acidic conditions and with the larger the current and the larger the air flow lead to the greater the ozone concentration in the water.The higher the concentration of ozone in the water and the shorter the equilibrium time required for decomposition,and the ozone dissolution and decomposition process conforms to the pseudo first-order kinetics process.Ozone oxidation degradation of CFX system alone showed that the degradation rate was 63% at pH=11,air flow rate was 3 L/min,ozone generator current was 0.8 A,and CFX initial concentration was 100 mg/L.In addition,the process accords with pseudo-first-order kinetics.The homogeneous ozone catalytic oxidation uses Fe(II),Mn(II)and Cu(II)as catalysts.The results show that the degradation rate of CFX is obviously improved and the degradation rate of different types of catalysts at different concentrations and different pH is also different.The best degradation effect was achieved when Fe(II)concentration was 1 mg/L,pH=6.3,Cu(II)=1.3 mg/L,pH=11,Mn(II)=1.5 mg/L,pH=11.The CFX of degradation rates were 85%,83%,and 77%,respectively,and the process was consistent with the first-order kinetic process.Heterogeneous catalytic ozonation was carried out by using diatomaceous earth as carrier to support the above three transition metal ions.The apparent morphology and chemical composition of supported diatomite by SEM ?XRD and IR indicate that the metal ions have been successfully loaded.Under different pH and catalyst dosage,the degradation rates reached 94%,93% and 87.7% respectively which accorded with pseudo-second-order kinetics.It was speculated by UV-Vis that the reaction intermediates,which indicated that the CFX molecular chain was broken during the reaction to form a new substance.The rate of ·OH production in the reaction was analyzed by fluorescence spectrophotometry.The effect of ·OH in the degradation of CFX was analyzed by the free radical inhibitor TBA.Degradation simulation of actual wastewater shows that it can effectively improve the biodegradability of CFX wastewater.