title: Kinetics and thermodynamics studies of silver ions adsorption onto coconut shell activated carbon.
abstract: The presence of silver in the natural water environment has been of great concern because of its toxicity, especially when it is in the free ion form (Ag(+)). This paper aims to study the adsorption kinetics of silver ions from an aqueous solution onto coconut shell activated carbon using batch methods. Batch kinetic data were fitted to the first-order model and the pseudo-second-order model, and this last equation fits correctly the experimental data. Equilibrium experiments were carried out at 30°C, 40°C, and 50°C. The adsorption isotherms were reasonably fit using Langmuir model, and the adsorption process was slightly influenced by changes in temperature. Thermodynamic parameters (ΔH°, ΔG°, and ΔS°) were determined. The adsorption process seems to be non-favorable, exothermic, and have an increase in the orderness.
authors.affiliation: a Academic Department of Environmental , Technological Federal University of Paraná - UTFPR , Campo Mourão , PR , Brazil.
authors.forename: Flávia V
authors.initials: FV
authors.lastname: Silva-Medeiros
authors.affiliation: a Academic Department of Environmental , Technological Federal University of Paraná - UTFPR , Campo Mourão , PR , Brazil.
authors.forename: Nelson
authors.initials: N
authors.lastname: Consolin-Filho
authors.affiliation: a Academic Department of Environmental , Technological Federal University of Paraná - UTFPR , Campo Mourão , PR , Brazil.
authors.forename: Mateus
authors.initials: M
authors.lastname: Xavier de Lima
authors.affiliation: a Academic Department of Environmental , Technological Federal University of Paraná - UTFPR , Campo Mourão , PR , Brazil.
authors.forename: Fernando Previato
authors.initials: FP
authors.lastname: Bazzo
authors.affiliation: b Department of Chemistry Engineering , State University of Maringá - UEM , Maringá , PR , Brazil.
authors.forename: Maria Angélica S D
authors.initials: MA
authors.lastname: Barros
authors.affiliation: b Department of Chemistry Engineering , State University of Maringá - UEM , Maringá , PR , Brazil.
authors.forename: Rosângela
authors.initials: R
authors.lastname: Bergamasco
authors.affiliation: b Department of Chemistry Engineering , State University of Maringá - UEM , Maringá , PR , Brazil.
authors.forename: Célia R G
authors.initials: CR
authors.lastname: Tavares
mesh_terms: D000327:Adsorption; D002244:Carbon / Q000737:chemistry*; D003059:Cocos; D007700:Kinetics; D008956:Models, Chemical; D012834:Silver / Q000737:chemistry*; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; D012834:Silver; D002244:Carbon
keywords: Adsorption; activated carbon; kinetics and thermodynamics; silver