title: Sorption and desorption of silver ions by bentonite clays.
abstract: Anthropogenic activities have increased the concentration of metal species in the environment. The toxicity of silver ions to aquatic and terrestrial organisms has required monitoring by analytical methods, besides actions to promote its control as pollutant. Sorption and desorption processes are directly related to the mobility and availability of metal ions in the environment. In this context, clay minerals can be used for pre-concentration, removal and recovery of silver ions from aqueous solution. Herein, two bentonite clays (BaVC-1 and SWy-2) were characterised and applied to investigate the sorption and desorption of silver ions. Isotherms were fitted to the dual-mode Langmuir-Freundlich model to qualify and quantify sorption sites and evaluate the mobilisation process. The maximum sorption capacity was 743 and 849 meq kg-1for BaVC-1 and SWy-2, respectively. Hysteresis index (HI) and mobilisation factor (MF) suggest that the desorption of silver ions in BaVC-1 is about four times more conducive compared to that in SWy-2, although both materials have demonstrated a great potential for Ag+pre-concentration from aqueous solutions.
authors.affiliation: Departamento de Química, Universidade Estadual de Londrina, Rod. Celso Garcia Cid-PR445, Londrina, Paraná, 86051-990, Brazil.
authors.forename: Leonel Vinicius
authors.initials: LV
authors.lastname: Constantino
authors.affiliation: Departamento de Química, Universidade Estadual de Londrina, Rod. Celso Garcia Cid-PR445, Londrina, Paraná, 86051-990, Brazil.
authors.forename: Juliana Nunes
authors.initials: JN
authors.lastname: Quirino
authors.affiliation: Departamento de Química, Universidade Estadual de Londrina, Rod. Celso Garcia Cid-PR445, Londrina, Paraná, 86051-990, Brazil.
authors.forename: Alessandra Maffei
authors.initials: AM
authors.lastname: Monteiro
authors.affiliation: Department of Electrical Engineering (DEEL), State University of Londrina (UEL), Rod. Celso Garcia Cid - PR445, s/n, Campus Universitário, P.O. Box 10.011 86057-970, Londrina, PR, Brazil.
authors.forename: Taufik
authors.initials: T
authors.lastname: Abrão
authors.affiliation: Departamento de Física, Universidade Estadual de Londrina, Rod. Celso Garcia Cid-PR445, Londrina, Paraná, 86051-990, Brazil.
authors.forename: Paulo Sérgio
authors.initials: PS
authors.lastname: Parreira
authors.affiliation: Departamento de Física, Universidade Estadual de Londrina, Rod. Celso Garcia Cid-PR445, Londrina, Paraná, 86051-990, Brazil.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Urbano
authors.affiliation: Departamento de Química, Universidade Estadual de Londrina, Rod. Celso Garcia Cid-PR445, Londrina, Paraná, 86051-990, Brazil. mjyabe@uel.br.
authors.forename: Maria Josefa
authors.initials: MJ
authors.lastname: Santos
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry*; D001546:Bentonite / Q000737:chemistry*; D000077215:Clay; D006863:Hydrogen-Ion Concentration; D007477:Ions; D012834:Silver / Q000737:chemistry*
chemical_list: D000538:Aluminum Silicates; D007477:Ions; D001546:Bentonite; D012834:Silver; D000077215:Clay
keywords: Desorption; Environment; Montmorillonite; Silver; Sorption