Distinct effects of copper on the degradation of β-lactam antibiotics in fulvic acid solutions during light and dark cycle  

作　　者：Xinran Zhang Yiming Guo Yanheng Pan Xin Yang 

机构地区：[1]School of Environmental Science and Engineering,Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology,Sun Yat-sen University,Guangzhou,510275,China

出　　处：《Environmental Science and Ecotechnology》2020年第3期41-49,共9页环境科学与生态技术（英文）

基　　金：China’s National Key Research and Development Program(grant 2017YFE0133200);National Science Foundation of China(grants 51708562 and 21577178);Characteristic Innovation Projects of Universities in Guangdong province(grant 2018KTSCX001);Guangdong Basic and Applied Basic Research Foundation(2019A1515011664);the Fundamental Research Funds for the Central Universities(20lgzd22)for their financial support of this study.

摘　　要：This study revealed the dual roles of Cu(Ⅱ)on the β-lactam antibiotics degradation in Suwannee River fulvic acid(SRFA)solution during day and night cycle.Amoxicillin(AMX)and ampicillin(AMP)were selected as the representative β-lactam antibiotics.Cu(Ⅱ)played a key role in the dark degradation of AMX and AMP via catalytic hydrolysis and oxidation.However,Cu(Ⅱ)mainly exhibited an inhibitory effect on SRFA-involved photochemical degradation of AMX and AMP.In the presence of 500 nM of Cu(Ⅱ),the degradation rate of AMX and AMP in the light condition were around 5 times higher than that in the dark condition,suggesting the photodegradation of β-lactam antibiotics was much more pronounced than catalyzed hydrolysis and oxidation.The triplet excited state of SRFA(^(3)SRFA*)primarily contributed to AMX and AMP photodegradation.Hydroxyl radicals(·OH)and singlet oxygen(^(1)O_(2))exhibited limit impacts.The redox cycle of Cu(Ⅱ)/Cu(Ⅰ)restricted the electron transfer pathway of ^(3)SRFA* with AMX and AMP.During the day and night cycles for 48 h,Cu(Ⅱ)served as a stronger inhibitor rather than a promotor.These findings highlight the interactions between Cu(Ⅱ)and SRFA are distinct under day and night conditions,which could further affect the fate of β-lactam antibiotics in natural environments.

关 键 词：Amoxicillin(AMX) Ampicillin(AMP) Copper(Cu(Ⅱ)) Fulvic acid Day and night cycle 

分 类 号：O64[理学—物理化学]