title: Uptake properties of phosphate on a novel Zr-modified MgFe-LDH(CO(3)).
abstract: We prepared a novel Zr-modified MgFe-LDH(CO(3)) composite by adding a mixed solution of MgCl(2), FeCl(3), and ZrOCl(2) and another mixed solution of 1mol/dm(3) NaOH and 1mol/dm(3) Na(2)CO(3) to distilled water at a constant pH of 10. The composite exhibited only a poorly crystalline structure, resembling that of layered double hydroxides (LDH) from X-ray diffraction. The phosphate uptake is dependent on pH, decreasing with an increase in pH. This composite shows a much greater uptake of phosphate ions in P-enriched seawater (0.33mg-P/dm(3)) than amorphous zirconium oxide and MgFe-LDH(CO(3)). The uptake isotherm was fitted with a Freundlich relation. These phosphate-uptake behaviors closely resemble those of the relevant Zr-MgAl-LDH, which is estimated to be a composite of MgAl-LDH with amorphous zirconium hydroxide on the surface from X-ray absorption spectroscopy. Therefore, a similar structure of Zr-modified MgFe-LDH(CO(3)) composite probably causes the marked increase in phosphate uptake from P-enriched seawater.
authors.affiliation: Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 2217-14 Hayashi-cho, Takamatsu 761-0395, Japan. chitrakar-ramesh@aist.go.jp
authors.forename: Ramesh
authors.initials: R
authors.lastname: Chitrakar
authors.forename: Satoko
authors.initials: S
authors.lastname: Tezuka
authors.forename: Junji
authors.initials: J
authors.lastname: Hosokawa
authors.forename: Yoji
authors.initials: Y
authors.lastname: Makita
authors.forename: Akinari
authors.initials: A
authors.lastname: Sonoda
authors.forename: Kenta
authors.initials: K
authors.lastname: Ooi
authors.forename: Takahiro
authors.initials: T
authors.lastname: Hirotsu
mesh_terms: D000327:Adsorption; D006878:Hydroxides / Q000737:chemistry*; D010710:Phosphates / Q000302:isolation & purification*; D012623:Seawater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D014961:X-Ray Diffraction; D015040:Zirconium / Q000737:chemistry*
chemical_list: D006878:Hydroxides; D010710:Phosphates; D014874:Water Pollutants, Chemical; C470523:zirconium hydroxide; D015040:Zirconium