| Recently,a large number of?-lactam antibiotics have been used to enter the environment through the treatment of human disease,livestock breeding and aquaculture.However,the presence of high concentration of antibiotics in the environment causes microbes to produce resistance and anti-drug genes,causing potential threats to human health and the ecological environment.Therefore,how to effectively and environmentally friendly removal of such pollutants from the environment is of great significance.This paper uses persulfate?PS,PMS?,Potassium Permanganate?KMnO4?and hydrogen peroxide?H2O2?as the oxidant,and then test of?-lactam antibiotics removal effect analysis of degradation under different reaction conditions,finally using high performance liquid chromatography mass spectrometry instrument?LC-MS?of?-lactam antibiotics degradation products and the path was proposed.Firstly,the reaction rate of?-lactams in the PMS system is accelerated with the increase of the concentration of PMS and the whole reaction process belongs to the second order reaction.On the contrary,the degradation rate of?-lactams decreased with the increase of its concentration,pH and humic acid content.In the process of PMSsystem,there is no sulfate radical?SO4-·?generated,which belongs to the non-radical reaction.Its active site is located on the S of the lactam ring,and finally produces two kinds of sulfoxide products.The oxidation efficiency of the system is not affected by various inorganic anions in the water.Finally,in the different water matrixes,the removal efficiency of?-lactams in thePMS system is followed by river,lake and sewage.Secondly,in the UV/PS system,the removal rate of?-lactams was increased with PS concentration increasing and the reaction fit the pseudo first-order kinetics.Under acidic conditions,it is beneficial to degradation of?-lactams in UV/PS system.Adding MA and TBA,the removal rate of?-lactams was decreased significantly.It show that in this process,SO4-·and HO·were generated and has acertain mineralization.Finally,the presence of chloride ions?Cl-?in water promotes the degradation of?-lactams.Last,we identified the second order reaction rate constants of?-lactams at UV/H2O2 and Potassium Permanganate systems,respectively.Compared with Potassium Permanganate,UV/H2O2 and PMS oxidation system of the pseudo first-order apparent reaction rate showed PMS system oxidate?-lactams degradation more easily,no matter where the oxidation reaction rate of cephalosporins is faster than penicillin.In a word,the mechanism of the oxidation of PMS is non-radical reaction,which mainly involves the oxidation of thioether.The reaction of free radicals in the UV/PS system is the main effect of the radical radical of the sulfate radical.Finally,the oxidation capacity determines the oxidation degradation of antibiotics.This study provides theoretical basis and technical support for the remediation of contaminated environment by?-lactams.In practical significance and social value,it is important for China which is a big country in antibiotic use. |
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