title: Interaction of ciprofloxacin and probe compounds with palygorskite PFl-1.
abstract: The adsorption of ciprofloxacin (CIP) as well as probe compounds, phenylpiperazine (PP) (NH) and fluorochloroquinolone carboxylic acid (FCQCA) (COOH), on palygorskite (PFl-1) obeyed the Langmuir isotherm at pH 2, 7, and 11 except the FCQCA adsorption at pH 2. The CIP and PP adsorption onto PFl-1 was 98-160 mmol/kg. In neutral solution the total amount of exchangeable cations desorbed correlated with the adsorbed amount of CIP and PP well with a slope of 0.9-1, indicating a cation-exchange mechanism. A low amount of FCQCA adsorption of 27-57 mmol/kg was observed and the amount of exchangeable cations desorbed negatively correlate with the amount of FCQCA adsorbed as influenced by surface complexation or cation bridging. FTIR band shifting due to the ring-stretch vibration of PP and the keto-carbonyl group stretching of FCQCA suggested strong interactions as PP and FCQCA absorbed on PFl-1 in neutral solution. In the interaction of CIP with PFl-1, the piperazine-amine group played an important role in cation-exchange interaction in acidic to neutral solution, while the deprotonated keto carbonyl group actively partook in cation bridging or surface complexation with metal cations adsorbed on PFl-1 when the CIP was in anionic form in alkaline solution.
authors.affiliation: Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan.
authors.forename: Po-Hsiang
authors.initials: PH
authors.lastname: Chang
authors.affiliation: Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan. Electronic address: atwtj@mail.ncku.edu.tw.
authors.forename: Wei-Teh
authors.initials: WT
authors.lastname: Jiang
authors.affiliation: Department of Geosciences, University of Wisconsin-Parkside, 900 Wood Road, Kenosha, WI 53144, USA. Electronic address: li@uwp.edu.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Public Health, College of Health Care and Management, Chung Shan Medical University, No. 110, Sec. 1, Chien-Kuo N Road, Taichung 40242, Taiwan.
authors.forename: Chung-Yih
authors.initials: CY
authors.lastname: Kuo
authors.affiliation: College of Physics and Technology, Yangtze University, Jingzhou, Hubei 434023, China.
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan.
authors.forename: Jiin-Shuh
authors.initials: JS
authors.lastname: Jean
authors.affiliation: School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Lv
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000737:chemistry*; D002939:Ciprofloxacin / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007474:Ion Exchange; D017616:Magnesium Compounds / Q000737:chemistry*; D017655:Silicon Compounds / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D017616:Magnesium Compounds; D017655:Silicon Compounds; D002939:Ciprofloxacin; C026325:attapulgite
keywords: Adsorption; Cation bridging; Cation exchange; Ciprofloxacin; Palygorskite