title: Uptake and retention of amitriptyline by kaolinite.
abstract: As the most commonly prescribed tricyclic antidepressant, amitriptyline (AT) is frequently detected in wastewater, surface runoff, and effluents from sewage treatment plants, and could potentially reach agriculture land through the application of municipal biosolids or reclaimed water. Kaolinite is one of the most important soil components under warm and humid climate conditions. In this study, the uptake and retention of AT by kaolinite from aqueous solution were investigated by batch tests, XRD, and FTIR analyses. The uptake of AT on kaolinite was instantaneous, attributed to surface adsorption as confirmed by XRD analyses. Quantitative correlation between desorption of exchangeable cations and AT adsorption confirmed experimentally that cation exchange was the dominant mechanism of AT uptake on kaolinite. The values for free energy of adsorption also suggested physi-sorption such as cation exchange. Solution pH had minimal influence at pH 5-11 even though the pKa value of AT was 9.4 and the surface charge of kaolinite was pH-dependent.
authors.affiliation: School of Materials Science and Technology, China University of Geosciences, Beijing 100083, China.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Lv
authors.forename: Christie
authors.initials: C
authors.lastname: Stockwell
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Niles
authors.forename: Skylar
authors.initials: S
authors.lastname: Minegar
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Li
authors.forename: Wei-Teh
authors.initials: WT
authors.lastname: Jiang
mesh_terms: D000327:Adsorption; D000639:Amitriptyline / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007616:Kaolin / Q000737:chemistry*; D007700:Kinetics; D009994:Osmolar Concentration; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D012996:Solutions; D000639:Amitriptyline; D007616:Kaolin
keywords: Amitriptyline; Cation exchange; FTIR; Kaolinite; Retention; Uptake