title: Montmorillonite enhanced ciprofloxacin transport in saturated porous media with sorbed ciprofloxacin showing antibiotic activity.
abstract: Antibiotic ciprofloxacin (CIP) is immobile in the subsurface but it has been frequently detected in the aquatic system. Therefore it is important to investigate the factors impacting CIP's mobilization in aquifer. Laboratory columns packed with sand were used to test colloid-facilitated CIP transport by 1) using kaolinite or montmorillonite to mobilize presorbed-CIP in a column or 2) co-transporting with CIP by pre-mixing them before transport. The Langmuir model showed that CIP sorption by montmorillonite (23gkg(-1)) was 100 times more effective than sand or kaolinite. Even with strong CIP complexation ability to Fe/Al coating on sand surface, montmorillonite promoted CIP transport, but not kaolinite. All presorbed-CIP by sand was mobilized by montmorillonite after 3 pore volumes through co-transporting of CIP with montmorillonite. The majority of CIP was fixed onto the montmorillonite interlayer but still showed inhibition of bacteria growth. Our results suggested that montmorillonite with high CIP sorption ability can act as a carrier to enhance CIP's mobility in aquifer.
authors.affiliation: Department of Soil and Water Science, University of Florida, Gainesville, FL 32611, United States.
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL 32611, United States.
authors.forename: Bin
authors.initials: B
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 210046, China.
authors.forename: Liu-Yan
authors.initials: LY
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 210046, China; Department of Soil and Water Science, University of Florida, Gainesville, FL 32611, United States. Electronic address: lqma@ufl.edu.
authors.forename: Lena Q
authors.initials: LQ
authors.lastname: Ma
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D001546:Bentonite / Q000737:chemistry*; D002939:Ciprofloxacin / Q000737:chemistry* / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects; D060587:Groundwater / Q000737:chemistry; D007616:Kaolin / Q000737:chemistry*; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D014874:Water Pollutants, Chemical; D001546:Bentonite; D007616:Kaolin; D002939:Ciprofloxacin; D012822:Silicon Dioxide
keywords: Ciprofloxacin; Colloid; Kaolinite; Montmorillonite; Transport