title: Sorption of tetracycline on organo-montmorillonites.
abstract: Tetracycline (TC) is a veterinary antibiotic that is frequently detected as pollutant in the environment. Powerful adsorbents are required for removing TC. The present paper compares the TC adsorption capacity of Na-montmorillonite (Na-mont) with six organo-montmorillonites (organo-monts). Three quaternary ammonium cations (QACs) with different alkyl-chain lengths were used as modifiers. Powder X-ray diffraction indicated that the d(001) values of organo-monts increased with increasing the QACs loading and alkyl-chain length. The CECs of the organo-monts were substantially lower than that of Na-mont and decreased with QACs chain length and increased loading. The modeling of the adsorption kinetics revealed that the processes of TC adsorption on the tested samples could be well fitted by the pseudo-second-order equation. The maximum adsorption capacities of TC on the organo-monts (1000-2000mmol/kg) were considerably higher than that on Na-mont (769mmol/kg). Both the Langmuir and Freundlich model could fit the adsorption isotherms. The TC adsorption to the organo-monts increase significantly with decreasing the pH below 5.5 because of the electrostatic interaction, and a high QACs loading performed better than a low loading at around pH 3.
authors.affiliation: College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, PR China.
authors.forename: Niu
authors.initials: N
authors.lastname: Liu
authors.forename: Ming-xia
authors.initials: MX
authors.lastname: Wang
authors.forename: Ming-ming
authors.initials: MM
authors.lastname: Liu
authors.forename: Fan
authors.initials: F
authors.lastname: Liu
authors.forename: Liping
authors.initials: L
authors.lastname: Weng
authors.forename: Luuk K
authors.initials: LK
authors.lastname: Koopal
authors.forename: Wen-feng
authors.initials: WF
authors.lastname: Tan
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000737:chemistry*; D001546:Bentonite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D033362:Powder Diffraction; D013501:Surface-Active Agents / Q000737:chemistry; D013752:Tetracycline / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; D001546:Bentonite; D013752:Tetracycline