title: Halide removal from aqueous solution by novel silver-polymeric materials.
abstract: The objective of this study was to analyze the behavior of a new material, silver-doped polymeric cloth (Ag-cloth), in the removal of bromide and iodide from waters. Silver is immobilized on the cloth, guaranteeing selective adsorption of the halide ions as retained silver halides that therefore do not pass into the solution. Results indicate that Ag0reacts with H2O2in the first phases of the process, yielding Ag+and superoxide radical; however, as the process advances, this radical favors Ag+reduction. Increases in the concentration of H2O2augment the capacity of the Ag-cloth to remove halides from the medium up to a maximum concentration (55μM), above which the removal capacity remains constant (Xm≅1.3-1.8mg halide/g Ag-cloth). Thus, when there is excess H2O2in the medium, secondary competitive reactions that take place in the process guarantee a constant Ag+concentration, which defines the maximum adsorption capacity of Ag-cloth, reducing its ability to remove halides. Ag-cloth has a higher capacity to remove iodide than bromide, and the presence of organic matter or chloride reduces its capacity to remove iodide or bromide from water. The results obtained shown that the capacity of Ag0with H2O2significantly varies as a function of the medium pH from 1mg Br-/g Ag-cloth at very low pH to 1.6mg/g Ag-cloth at pH9.
authors.affiliation: Department of Inorganic Chemistry, University of Granada. 18071, Granada, Spain.
authors.forename: Polo
authors.initials: P
authors.lastname: A M S
authors.affiliation: Department of Inorganic Chemistry, University of Granada. 18071, Granada, Spain.
authors.forename: Velo-Gala
authors.initials: VG
authors.lastname: I
authors.affiliation: Department of Inorganic Chemistry, University of Granada. 18071, Granada, Spain; Eawag, Swiss Federal Institute for Aquatic Science and Technology, CH-8600, Dübendorf, Switzerland.
authors.forename: Sánchez-Polo
authors.initials: SP
authors.lastname: M
authors.affiliation: Eawag, Swiss Federal Institute for Aquatic Science and Technology, CH-8600, Dübendorf, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytecnique Fédérale de Lausanne, Ch-1015 Lausanne, Switzerland.
authors.forename: von Gunten
authors.initials: VG
authors.lastname: U
authors.affiliation: Department of Inorganic Chemistry, University of Granada. 18071, Granada, Spain.
authors.forename: López-Peñalver
authors.initials: LP
authors.lastname: J J
authors.affiliation: Department of Inorganic Chemistry, University of Granada. 18071, Granada, Spain.
authors.forename: Rivera-Utrilla
authors.initials: RU
authors.lastname: J
mesh_terms: D000327:Adsorption; D001965:Bromides / Q000032:analysis*; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007454:Iodides / Q000032:analysis*; D011109:Polymethacrylic Acids / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D012965:Sodium Chloride / Q000032:analysis; D012996:Solutions; D013499:Surface Properties; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
chemical_list: D001965:Bromides; D007454:Iodides; D011109:Polymethacrylic Acids; D012996:Solutions; D014874:Water Pollutants, Chemical; D012834:Silver; D012965:Sodium Chloride; D006861:Hydrogen Peroxide
keywords: Ag-cloth; H(2)O(2); Halide; Selective chemisorption