The adsorption behaviors of ciprofloxacin(CIP),a fluoroquinolone antibiotic,onto goethite(Gt)in the presence of silver and titanium dioxide nanoparticles(AgNPs and TiO2NPs)were investigated.Results showed that CIP adsorption kinetics in Gt with or without NPs both followed the pseudo-second-order kinetic model.The presence of AgNPs or TiO2NPs inhib-ited the adsorption of CIP by Gt.The amount of inhibition of CIP sorption due to AgNPs was decreased with an increase of solution pH from 5.0 to 9.0.In contrast,in the presence of TiO2NPs,CIP adsorption by Gt was almost unchanged at pHs of 5.0～6.5 but was decreased with an increase of pH from 6.5 to 9.0.The mechanisms of AgNPs and TiO2NPs in inhibiting CIP adsorption by Gt were different,which was attributed to citrate coating of AgNPs result-ing in competition with CIP for adsorption sites on Gt,while TiO2NPs could compete with Gt for CIP adsorption.Additionally,CIP was adsorbed by Gt or TiO2NPs through a tridentate complex involving the bidentate inner-sphere coordination of the deprotonated carboxylic group and hydrogen bonding through the adjacent carbonyl group on the quinoline ring.These findings advance our understanding of the environmental behavior and fate of fluo-roquinolone antibiotics in the presence of NPs.

Jie Tang;Yun Wang;Qiang Xue;Fei Liu;Kenneth C.Carroll;Xiaohua Lu;Taogeng Zhou;Dengjun Wang

MOE Key Laboratory of Groundwater Circulation and Environmental Evolution,China University of Geosciences(Beijing),Beijing 100083,China;Beijing Key Laboratory of Water Resources and Environmental Engineering,School of Water Resources and Environment,China University of Geosciences(Beijing),Beijing 100083,China;Water Science and Management Program,New Mexico State University,MSC 3Q,USA;Plant&Environmental Science,New Mexico State University,Las Cruces,NM 88003,USA;National Institute of Metrology,Beijing 100022,China;Beijing Institute of Technology,Beijing 100081,China;School of Fisheries,Aquaculture and Aquatic Sciences,Auburn University,Auburn,AL 36849,USA

环境科学学报（英文版）

[1]Jie Tang;Yun Wang;Qiang Xue;Fei Liu;Kenneth C.Carroll;Xiaohua Lu;Taogeng Zhou;Dengjun Wang-.A mechanistic study of ciprofloxacin adsorption by goethite in the presence of silver and titanium dioxide nanoparticles)[J].环境科学学报（英文版）,2022(08):46-56

pHs,roquinolone

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