title: Sorption, degradation and transport phenomena of alcohol ethoxysulfates in agricultural soils. Laboratory studies.
abstract: In the present work, laboratory studies were conducted in order to determine and model the sorption, degradation and transport processes of alcohol ethoxysulfates (AES), one of the most important groups of anionic surfactants. Adsorption/desorption isotherms were obtained for several structurally related AES ethoxymers (homologue AES-C12Enwith n = 0-10 ethoxymer units and homologue AES-C14Enwith n = 0-7 ethoxymer units) using a batch equilibrium method. Data were fitted to a linear and a Freundlich isotherm models. Additionally, experiments in continuous-flow soil columns were also carried out and the breakthrough curves observed for each compound were studied. Breakthrough curves were used to determine the fundamental parameters of the transport model (hydrodynamic dispersion coefficient, degradation rate constant and adsorption/desorption isotherm slope), that is the main phenomena that take place simultaneously when AES move through agricultural soil. When the results obtained for the AES ethoxymers are combined, they reveal a clear and consistent trend towards a sorption increase with the number of ethoxylated units and with the length of the alkyl chain that opens the possibility to estimate the values of the transport parameters for other structurally related ethoxymers.
authors.affiliation: Research Group of Analytical Chemistry and Life Sciences, Department of Analytical Chemistry, Faculty of Sciences, University of Granada, Granada, Spain. Electronic address: cfr@ugr.es.
authors.forename: C
authors.initials: C
authors.lastname: Fernández-Ramos
authors.affiliation: Research Group of Analytical Chemistry and Life Sciences, Department of Analytical Chemistry, Faculty of Sciences, University of Granada, Granada, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Rodríguez-Gómez
authors.affiliation: Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal.
authors.forename: M S
authors.initials: MS
authors.lastname: Reis
authors.affiliation: Research Group of Analytical Chemistry and Life Sciences, Department of Analytical Chemistry, Faculty of Sciences, University of Granada, Granada, Spain. Electronic address: azafra@ugr.es.
authors.forename: A
authors.initials: A
authors.lastname: Zafra-Gómez
authors.affiliation: Cepsa Química, Avenida del Partenón 12, E-28042, Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Verge
authors.affiliation: Cepsa Química, Avenida del Partenón 12, E-28042, Madrid, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: de Ferrer
authors.affiliation: Cepsa Química, Avenida del Partenón 12, E-28042, Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Pérez-Pascual
authors.affiliation: Research Group of Analytical Chemistry and Life Sciences, Department of Analytical Chemistry, Faculty of Sciences, University of Granada, Granada, Spain.
authors.forename: J L
authors.initials: JL
authors.lastname: Vílchez
mesh_terms: D000327:Adsorption; D000383:Agriculture; D008962:Models, Theoretical; D012987:Soil; D012989:Soil Pollutants / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D012987:Soil; D012989:Soil Pollutants; D013431:Sulfates; D013501:Surface-Active Agents
keywords: Alcohol ethoxysulfates; Continuous soil column experiments; Ethoxymers; Freundlich isotherm; Sorption models