Trimethoprim(TMP)is a typical antibiotic to treat infectious disease,which is among the most commonly detected antibacterial agents in natural waters and municipal wastewaters.In the present study,the impacts of disso...Trimethoprim(TMP)is a typical antibiotic to treat infectious disease,which is among the most commonly detected antibacterial agents in natural waters and municipal wastewaters.In the present study,the impacts of dissolved oxygen(DO)on the oxidation efficiency and pathways of TMP by reaction with sulfate radicals(SO_(4)^(-1))were investigated.Our results revealed that the presence of DO was favourable for TMP degradation.Specifically,TMP would react initially with SO_(4)^(-1)via electron-transfer process to form a carbon-centered radical.In the absence of oxygen,the carbon-centered radical could undergo hydrolysis to produceα-hydroxytrimethoprim(TMPàOH),followed by the further oxidation which generatedα-ketotrimethoprim(TMP=O).However,in the presence of oxygen,the carbon-centered radical would alternatively combine with oxygen,leading to a sequential reaction in which peroxyl radical and a tetroxide were formed,and finally generated TMPàOH and TMP=O simultaneously.The proposed pathways were further confirmed by density functional theory(DFT)calculations.The results obtained in this study would emphasize the significance of DO on the oxidation of organic micropollutants by SO_(4)^(-1).展开更多
基金financially supported by the National Natural Science Foundation of China(No.21806037)。
文摘Trimethoprim(TMP)is a typical antibiotic to treat infectious disease,which is among the most commonly detected antibacterial agents in natural waters and municipal wastewaters.In the present study,the impacts of dissolved oxygen(DO)on the oxidation efficiency and pathways of TMP by reaction with sulfate radicals(SO_(4)^(-1))were investigated.Our results revealed that the presence of DO was favourable for TMP degradation.Specifically,TMP would react initially with SO_(4)^(-1)via electron-transfer process to form a carbon-centered radical.In the absence of oxygen,the carbon-centered radical could undergo hydrolysis to produceα-hydroxytrimethoprim(TMPàOH),followed by the further oxidation which generatedα-ketotrimethoprim(TMP=O).However,in the presence of oxygen,the carbon-centered radical would alternatively combine with oxygen,leading to a sequential reaction in which peroxyl radical and a tetroxide were formed,and finally generated TMPàOH and TMP=O simultaneously.The proposed pathways were further confirmed by density functional theory(DFT)calculations.The results obtained in this study would emphasize the significance of DO on the oxidation of organic micropollutants by SO_(4)^(-1).
