title: Sorption kinetics of diuron on volcanic ash derived soils.
abstract: Diuron sorption kinetic was studied in Andisols, Inceptisol and Ultisols soils in view of their distinctive physical and chemical properties: acidic pH and variable surface charge. Two types of kinetic models were used to fit the experimental dates: those that allow to establish principal kinetic parameters and modeling of sorption process (pseudo-first-order, pseudo-second-order), and some ones frequently used to describe solute transport mechanisms of organic compounds on different sorbents intended for remediation purposes (Elovich equation, intraparticle diffusion, Boyd, and two-site nonequilibrium models). The best fit was obtained with the pseudo-second-order model. The rate constant and the initial rate constant values obtained through this model demonstrated the behavior of Diuron in each soil, in Andisols were observed the highest values for both parameters. The application of the models to describe solute transport mechanisms allowed establishing that in all soils the mass transfer controls the sorption kinetic across the boundary layer and intraparticle diffusion into macropores and micropores. The slowest sorption rate was observed on Ultisols, behavior which must be taken into account when the leaching potential of Diuron is considered.
authors.affiliation: Laboratorio de Fisicoquímica & Analítica, Departamento de Química, Facultad de Ciencias Básicas, Universidad Metropolitana de Ciencias de la Educación, Avenida José Pedro Alessandri 540, Santiago, Chile. Electronic address: lyzethly.caceres@umce.cl.
authors.forename: Lizethly
authors.initials: L
authors.lastname: Cáceres-Jensen
authors.forename: Jorge
authors.initials: J
authors.lastname: Rodríguez-Becerra
authors.forename: Joselyn
authors.initials: J
authors.lastname: Parra-Rivero
authors.forename: Mauricio
authors.initials: M
authors.lastname: Escudey
authors.forename: Lorena
authors.initials: L
authors.lastname: Barrientos
authors.forename: Vicente
authors.initials: V
authors.lastname: Castro-Castillo
mesh_terms: D000327:Adsorption; D004237:Diuron / Q000737:chemistry*; D006540:Herbicides / Q000737:chemistry*; D007700:Kinetics; D008962:Models, Theoretical; D012989:Soil Pollutants / Q000737:chemistry*; D018707:Volcanic Eruptions
chemical_list: D006540:Herbicides; D012989:Soil Pollutants; D004237:Diuron
keywords: Andisols; Inceptisols; Phenylurea herbicides; Sorption kinetic; Ultisols; Variable charge soils