title: [Impacts of pH and surfactants on adsorption behaviors of norfloxacin on marine sediments].
abstract: The adsorption behaviors of norfloxacin (NOR) on marine sediments at different pH values and in the presence of four different surfactants were systematically investigated by a batch equilibrium method. The results indicated that Freundlich adsorption isotherms fitted the adsorption behavior of NOR on marine sediments very well at different pH values. The Freundlich constant K(F) and the equilibrium adsorption amount of NOR reduced with the increase of pH values, and the minimum appeared at pH 8.10. The results suggested that cation exchange was the main adsorption mechanism of NOR at pH 6.01, while Van der Waals' force, hydrophobic effects, electrostatic force were the major adsorption mechanism of NOR on marine sediments at pH 8.10. The adsorption process fitted well with pseudo-second-order kinetic equations with the addition of surfactants. Our study also indicated that the addition of surfactants had the significant influence on the saturated adsorption amount of adsorption of NOR. The equilibrium adsorption amount (Q(e)) of NOR exhibited the following sequence: Q(e) (Tween80) < Q(e) (Tween20) <Q(e)(No) < Q(e) (CTAB) < Q(e)(SDBS).
authors.affiliation: Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, China. pang.huiling@163.com
authors.forename: Hui-Ling
authors.initials: HL
authors.lastname: Pang
authors.forename: Gui-Peng
authors.initials: GP
authors.lastname: Yang
authors.forename: Xian-Chi
authors.initials: XC
authors.lastname: Gao
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Cao
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009643:Norfloxacin / Q000032:analysis / Q000737:chemistry*; D009792:Oceans and Seas; D012623:Seawater / Q000032:analysis*; D013501:Surface-Active Agents / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; D009643:Norfloxacin