title: Enhanced removal of triphosphate by MgCaFe-Cl-LDH: synergism of precipitation with intercalation and surface uptake.
abstract: Triphosphate (TPP) is an important form of phosphate pollutants while its removal investigation has been just started now. This research examined the removal of triphosphate using Mg(2-x)Ca(x)FeCl-LDH (x = 0-2) as absorbents. We found that the removal of triphosphate over Mg(2)FeCl-LDH mainly underwent the surface adsorption and the near-edge intercalation, with the practical removal amount (9-11 mg(P)/g) corresponding to 10-15% of the theoretical one. In contrast, Ca(2)FeCl-LDH removed a higher amount of triphosphate (56.4 mg(P)/g). The comprehensive analysis of the triphosphate-uptake products with XRD/XPS/FTIR reveals that Ca(2)FeCl-LDH dissolves first and then released Ca(2+) ions react with triphosphate (TPP) to form insoluble Ca-TPP precipitate. Combination of these two different removal mechanisms enables Mg(0.5)Ca(1.5)FeCl-LDH to take up 84.2mg(P)/g from aqueous solution under similar conditions.
authors.affiliation: School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China.
authors.forename: Jizhi
authors.initials: J
authors.lastname: Zhou
authors.forename: Zhi Ping
authors.initials: ZP
authors.lastname: Xu
authors.forename: Shizhang
authors.initials: S
authors.lastname: Qiao
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liu
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Xu
authors.forename: Guangren
authors.initials: G
authors.lastname: Qian
mesh_terms: D000327:Adsorption; D002118:Calcium / Q000737:chemistry; D011232:Chemical Precipitation; D007501:Iron / Q000737:chemistry; D008274:Magnesium / Q000737:chemistry; D011122:Polyphosphates / Q000302:isolation & purification*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D011122:Polyphosphates; D014874:Water Pollutants, Chemical; D007501:Iron; D008274:Magnesium; C005692:triphosphoric acid; D002118:Calcium