title: Probing the interactions between chlorpheniramine and 2:1 phyllosilicates.
abstract: Interactions between chlorpheniramine (CP), an antihistamine drug used to treat allergy, and 2:1 phyllosilicates were studied under batch kinetic and different solution conditions to investigate the effect of charge density of the substrates on CP removal from solution. The CP removal by Na-montmorillonite was instantaneous, with a very large rate constant and a fast rate, reaching a capacity of 0.64 mmol/g, compared to its cation exchange capacity of 0.85 mmol(c)/g. In contrast, CP removal by talc was 10 times lower at 0.06 mmol/g. Stoichiometric desorption of exchangeable cations accompanying CP removal by Na-montmorillonite confirmed cation exchange as the dominant interaction mechanism. Solution pH had a minimal effect on CP removal by Na-montmorillonite until pH 11. On the contrary, a slight increase in CP removal by talc was observed as the solution pH increased, due to increased negative charges on the pH-dependent surfaces of talc. Interactions between CP and Na-montmorillonite occurred on both external and interlayer sites, resulting in a d-spacing expansion from 12.5 Å to 15.2 Å. In contrast, interactions between CP and talc were only limited to the external surfaces. It was the charge density that ultimately controlled the amount of CP removal by 2:1 phyllosilicates. Thus, montmorillonite offers a superior option for the removal of cationic drugs from aqueous solution.
authors.affiliation: School of Material Sciences and Technology, China University of Geosciences, Beijing 100083, China.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Lv
authors.forename: Liu
authors.initials: L
authors.lastname: Liu
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Li
authors.forename: Libing
authors.initials: L
authors.lastname: Liao
authors.forename: Meitang
authors.initials: M
authors.lastname: Liu
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry*; D001546:Bentonite / Q000737:chemistry*; D002744:Chlorpheniramine / Q000737:chemistry*; D005583:Fourier Analysis; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D012996:Solutions; D055672:Static Electricity; D013627:Talc / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification; D014961:X-Ray Diffraction
chemical_list: D000538:Aluminum Silicates; D012996:Solutions; D014874:Water Pollutants, Chemical; D001546:Bentonite; D013627:Talc; D002744:Chlorpheniramine