title: Preparation Behavior of the Mg-Fe Hydrotalcite by Urea Method and Its Cr(VI) Sorption Property.
abstract: The hydrotalcite of Mg6Fe2(OH)16CO3 x 4.5H2O were synthesized using urea method by adjusting the initial pH and urea amount in the reaction solution. The results showed that the co-precipitation of Mg2+ with Fe3+ cations formed Mg-Fe LDH occurring at pH 8.48-9.35. The pH played a crucial role in the Mg-Fe LDH precipitation by controlling urea/Fe3+ molar ratio in the reaction solution at 105 degrees C. The optimized urea/Fe3+ molar ratio was 12.0, where the relative yield of the Mg-Fe LDH was 80.0% and the Mg-Fe LDH was highly crystalline with small particle sizes (1-2 μm). The affinity of the Mg-Fe mixed oxide (Mg-Fe LDO) with Cr(VI) was studied as a function of contact time, initial pH, temperature of the solutions and calcined time of Mg-Fe LDH. The adsorption conditions were optimized using response surface methodology. The maximum adsorption capacity of 38.86 mg/g was achieved at 85 min with the conditions of initial pH 5.5, temperature 55 degrees C and calcined time 4 h. It was concluded that the Mg-Fe LDO can be used as an adsorbent to removal Cr(VI) in aqueous solutions.
authors.forename: Sheng
authors.initials: S
authors.lastname: Xu
authors.forename: MengChen
authors.initials: M
authors.lastname: Liao
authors.forename: HongYan
authors.initials: H
authors.lastname: Zeng
authors.forename: XiaoJun
authors.initials: X
authors.lastname: Liu
authors.forename: PeiHan
authors.initials: P
authors.lastname: Zhu
authors.forename: ChaoRong
authors.initials: C
authors.lastname: Chen
authors.forename: HengZhi
authors.initials: H
authors.lastname: Duan
mesh_terms: D000327:Adsorption; D000536:Aluminum Hydroxide / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D008274:Magnesium / Q000737:chemistry*; D008276:Magnesium Hydroxide / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties; D013696:Temperature; D014508:Urea / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D002857:Chromium; C010467:hydrotalcite; D000536:Aluminum Hydroxide; D014508:Urea; D007501:Iron; D008274:Magnesium; D008276:Magnesium Hydroxide