title: Removal of nickel ions from aqueous solution by low energy-consuming sorption process involving thermosensitive copolymers with phosphonic acid groups.
abstract: In order to remove metal ions from wastewaters, thermosensitive copolymers bearing sorption properties toward metal cations were prepared by free radical copolymerization between the N-n-propylacrylamide (NnPAAm) and the (dimethoxyphosphoryl)methyl 2-methylacrylate (MAPC1), followed by a hydrolysis of the phosphonated esters into phosphonic diacid groups ((h)MAPC1). The thermosensitivity and the sorption abilities of the resulting poly(NnPAAm-stat-(h)MAPC1) copolymers were studied. Lower Critical Solution Temperatures (LCST) of these copolymers ranged from 22 °C to 26 °C, depending on the molar ratio of phosphonated monomers and were lower than those obtained with usual poly(N-isopropylacrylamide)-based polymers. The influence of both the temperature and the pH on the sorption properties of the copolymers was evaluated for Ni(2+) cations. The most interesting results were obtained for temperatures around the LCST, i.e. when the proximity of the complexing groups favored the sorption of metallic cations. Concerning the pH effect, the maximum sorption capacity was obtained at pH 7, i.e. in the absence of competition between the sorption of H(+) and Ni(2+) ions on the phosphonic acid groups. The influence of the molar ratio of metal ions and phosphonate moieties was also studied and different sorption mechanisms were proposed.
authors.affiliation: Institut Europeen des Membranes-IEM (UMR 5635 CNRS-ENSCM-UM2) - Equipe Genie des Procedes Membranaires, Universite Montpellier II cc047, Place Eugene Bataillon, 34095 Montpellier Cedex 5, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Graillot
authors.forename: Denis
authors.initials: D
authors.lastname: Bouyer
authors.forename: Sophie
authors.initials: S
authors.lastname: Monge
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Robin
authors.forename: Catherine
authors.initials: C
authors.lastname: Faur
mesh_terms: D000179:Acrylates / Q000737:chemistry; D000327:Adsorption; D009532:Nickel / Q000737:chemistry*; D010757:Phosphorous Acids / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D012996:Solutions; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D000179:Acrylates; D010757:Phosphorous Acids; D011108:Polymers; D012996:Solutions; D014874:Water Pollutants, Chemical; C570063:phosphonic acid; D009532:Nickel