title: Removal of ciprofloxacin from water by birnessite.
abstract: With more pharmaceuticals and personal care products detected in the surface and waste waters, studies on interactions between these contaminants and soils or sediments have attracted great attention. In this study, the removal of ciprofloxacin (CIP), a fluoroquinolone antibiotic, by birnessite, a layered manganese oxide, in aqueous solution was investigated by batch studies supplemented by X-ray diffraction (XRD) and Fourier transform infrared analyses. Stoichiometric release of exchangeable cations accompanying CIP removal from water confirmed cation exchange as the major mechanism for CIP uptake by birnessite. Interlayer expansion after CIP adsorption on birnessite as revealed by XRD analyses indicated that intercalation contributed significantly to CIP uptake in addition to external surface adsorption. Correlation of CIP adsorption to specific surface area and cation exchange capacity suggested that the former was the limiting factor for CIP uptake. At the adsorption maximum, CIP molecules formed a monolayer on the birnessite surfaces. The adsorbed CIP could be partially removed using a cationic surfactant at a low initial concentration and mostly removed by AlCl3 at a higher initial concentration, which further supported the cation exchange mechanism for CIP removal by birnessite. The results indicated that the presence of layered Mn-oxide in the soil and waste water treatment systems may provide host for CIP accumulation.
authors.affiliation: Department of Earth Sciences, National Cheng Kung University, Tainan 70101, Taiwan. atwtj@mail.ncku.edu.tw
authors.forename: Wei-Teh
authors.initials: WT
authors.lastname: Jiang
authors.forename: Po-Hsiang
authors.initials: PH
authors.lastname: Chang
authors.forename: Ya-Siang
authors.initials: YS
authors.lastname: Wang
authors.forename: Yolin
authors.initials: Y
authors.lastname: Tsai
authors.forename: Jiin-Shuh
authors.initials: JS
authors.lastname: Jean
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Li
authors.forename: Keith
authors.initials: K
authors.lastname: Krukowski
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000032:analysis / Q000302:isolation & purification*; D002138:Calibration; D002412:Cations; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D002939:Ciprofloxacin / Q000032:analysis / Q000302:isolation & purification*; D024841:Fluoroquinolones / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D017895:Manganese Compounds / Q000737:chemistry; D010087:Oxides / Q000737:chemistry*; D013053:Spectrophotometry; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013501:Surface-Active Agents; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D002412:Cations; D002593:Cetrimonium Compounds; D024841:Fluoroquinolones; D017895:Manganese Compounds; D010087:Oxides; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; C505018:birnessite; D014867:Water; D002939:Ciprofloxacin; C027424:manganese oxide; D000077286:Cetrimonium