title: Removal of anionic pollutants by pine bark is influenced by the mechanism of retention.
abstract: The use of organic biosorbents for anion removal from water has been less studied than for cationic compounds. In this work, the removal capacity of pine bark for potential anionic pollutants (fluoride, phosphate, arsenate and dichromate) was assessed in column experiments, designed to study the process of transport. The results showed that pine bark has a very low retention capacity for phosphate, arsenate or fluoride, and in turn, very high for dichromate, with retention values close to 100% and less than 2% desorption of the adsorbed dichromate. The large differences observed between anions suggest that differences in the retention mechanism of each anion exist. In the case of phosphate and arsenate, electrostatic interactions with the mostly negatively charged functional groups of the pine bark determine the low retention capacity. Dichromate retention might proceed through reduction of chromium (VI) to chromium (III), what improves the efficiency of the removal.
authors.affiliation: Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola. Facultade de Ciencias de Ourense, As Lagoas s/n, 32004 Ourense, Spain. Electronic address: remigio.paradelo@uvigo.es.
authors.forename: R
authors.initials: R
authors.lastname: Paradelo
authors.affiliation: Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola. Facultade de Ciencias de Ourense, As Lagoas s/n, 32004 Ourense, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Conde-Cid
authors.affiliation: Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola. Facultade de Ciencias de Ourense, As Lagoas s/n, 32004 Ourense, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Arias-Estévez
authors.affiliation: Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola. Facultade de Ciencias de Ourense, As Lagoas s/n, 32004 Ourense, Spain.
authors.forename: J C
authors.initials: JC
authors.lastname: Nóvoa-Muñoz
authors.affiliation: Universidade de Santiago de Compostela, Departamento de Edafoloxía e Química Agrícola, Escola Politécnica Superior, Campus Univ. s/n, 27002 Lugo, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Álvarez-Rodríguez
authors.affiliation: Universidade de Santiago de Compostela, Departamento de Edafoloxía e Química Agrícola, Escola Politécnica Superior, Campus Univ. s/n, 27002 Lugo, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Fernández-Sanjurjo
authors.affiliation: Universidade de Santiago de Compostela, Departamento de Edafoloxía e Química Agrícola, Escola Politécnica Superior, Campus Univ. s/n, 27002 Lugo, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Núñez-Delgado
mesh_terms: D000327:Adsorption; D001149:Arsenates / Q000737:chemistry; D002840:Chromates / Q000737:chemistry; D005459:Fluorides / Q000737:chemistry; D010710:Phosphates; D028223:Pinus; D024301:Plant Bark / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D001149:Arsenates; D002840:Chromates; D010710:Phosphates; D014874:Water Pollutants, Chemical; D005459:Fluorides
keywords: Adsorption; Laboratory column; Organic matter; Transport experiment