title: Carbonated ferric green rust as a new material for efficient phosphate removal.
abstract: Phosphate uptake from aqueous solutions by a recently discovered ferric oxyhydroxide is investigated. Carbonated ferric green rust {GR(CO(3)(2-))*} is prepared by varying two synthesis parameters, which are (1) the aging period after the ferrous-ferric green rust {GR(CO(3)(2-))} synthesis step and (2) the rate of the hydrogen peroxide addition to oxidize GR(CO(3)(2-)) into GR(CO(3)(2-))*. These two parameters permit the control of the size, morphology and cristallinity of the synthesized particles. As prepared GR* samples are then evaluated, in batch experiments, as possible low-cost efficient phosphate removal materials. Firstly, kinetic experiments reveal that a fast sorption step initially occurs and equilibrium is reached at ~500 min. The adsorption kinetics data at pH=7 can be adequately fitted to a pseudo-second order model. Secondly, the Freundlich model provides the best correlation and effectively describes phosphate sorption isotherms for all GR(CO(3)(2-))* samples synthesized. Finally, the phosphate adsorption capacity decreases when pH increases. The highest adsorption capacity is 64.8 mg g(-1) at pH=4 and corresponds to the GR(CO(3)(2-))* sample displaying the smallest and least crystallized particles thus reflecting the importance of the synthesis conditions. Overall, all sorption capacities are higher than the main iron oxide minerals, making GR(CO(3)(2-))* a potentially attractive phosphate adsorbent.
authors: Laboratoire de Chimie Physique et Microbiologie pour l’Environnement (LCPME), UMR 7564 CNRS-Université de Lorraine, Villers-lès-Nancy, France.
authors: K
authors: K
authors: Barthélémy
authors: S
authors: S
authors: Naille
authors: C
authors: C
authors: Despas
authors: C
authors: C
authors: Ruby
authors: M
authors: M
authors: Mallet
mesh_terms: D000327:Adsorption; D002254:Carbonates / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D005618:Fresh Water / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D046529:Microscopy, Electron, Transmission; D010084:Oxidation-Reduction; D010316:Particle Size; D010710:Phosphates / Q000302:isolation & purification*; D012996:Solutions; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification
chemical_list: D002254:Carbonates; D005290:Ferric Compounds; D010710:Phosphates; D012996:Solutions; D014874:Water Pollutants, Chemical; C092844:ferric oxyhydroxide; D006861:Hydrogen Peroxide