title: Phosphate removal from aqueous solution using ZVI/sand bed reactor: Behavior and mechanism.
abstract: This research reports on phosphate removal from aqueous solution using ZVI/sand packed columns. The influence of column preconditioning, consisting of ZVI pre-oxidation before feeding the columns with phosphate solution, revealed that a column aged for 1 day was more efficient than un-conditioned column, 5-days and 10-days preconditioned columns. The distribution of phosphate trapped inside the columns was evaluated by measuring phosphate concentration in the solids at different levels (P1, P2 and P3) along the depth of the columns. The distribution of phosphate inside the columns was determined for a time period up to 46 days, corresponding to column saturation. Results showed heterogeneous trapping along the column before saturation and homogeneous distribution upon saturation. The maximum cumulative trapped phosphate after column dismantling was determined before saturation (after 17 days running) at 130, 68 and 31 mgP/gFe at the inlet-P1, P1-P2 and P2-P3 layers, respectively, whereas the homogeneous distribution of phosphate upon saturation was determined at 132 mgP/gFe throughout the column. Solid supports were characterized using SEM, XRD and XPS. Lepidocrocite and maghemite/magnetite were the only iron oxidation products identified at the different layers inside the columns. XPS results confirmed the sorption of phosphate at the surface of ZVI and its oxidation products and highlighted the formation of an iron phosphate complex.
authors.affiliation: Groupement de Recherche Eau Sol Environnement - GRESE EA 4330, University of Limoges, 123 Avenue Albert Thomas, Limoges, France; Platform for Research and Analysis in Environmental Sciences, Doctoral School of Science and Technology, Faculty of Sciences, Lebanese University, P.O. Box 5, Campus Rafic Hariri, Hadath, Beirut, Lebanon.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Sleiman
authors.affiliation: Groupement de Recherche Eau Sol Environnement - GRESE EA 4330, University of Limoges, 123 Avenue Albert Thomas, Limoges, France. Electronic address: veronique.deluchat@unilim.fr.
authors.forename: Véronique
authors.initials: V
authors.lastname: Deluchat
authors.affiliation: Lebanese American University, School of Engineering, Byblos, Lebanon.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Wazne
authors.affiliation: Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, CNRS - University of Lorraine, 405 rue de Vandoeuvre, F-54600 Villers-lès-Nancy, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Mallet
authors.affiliation: Groupement de Recherche Eau Sol Environnement - GRESE EA 4330, University of Limoges, 123 Avenue Albert Thomas, Limoges, France.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Courtin-Nomade
authors.affiliation: Platform for Research and Analysis in Environmental Sciences, Doctoral School of Science and Technology, Faculty of Sciences, Lebanese University, P.O. Box 5, Campus Rafic Hariri, Hadath, Beirut, Lebanon.
authors.forename: Véronique
authors.initials: V
authors.lastname: Kazpard
authors.affiliation: Groupement de Recherche Eau Sol Environnement - GRESE EA 4330, University of Limoges, 123 Avenue Albert Thomas, Limoges, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Baudu
mesh_terms: D007501:Iron; D010084:Oxidation-Reduction; D010710:Phosphates; D012822:Silicon Dioxide; D014874:Water Pollutants, Chemical
chemical_list: D010710:Phosphates; D014874:Water Pollutants, Chemical; D012822:Silicon Dioxide; D007501:Iron
keywords: Column experiments; Phosphate removal; Preconditioning effect; Sorption distribution; Zero valent iron