title: Chemical reactive features of novel amino acids intercalated layered double hydroxides in As(III) and As(V) adsorption.
abstract: Layered double hydroxides (LDHs) intercalated with amino acids such as methionine (Met) were synthesized as new adsorbents to remediate arsenic-polluted water. This Zn2Al-Met-LDHs, identified with the formula of Zn0.7Al0.3(OH)2(Met)0.3·0.32H2O, has good thermal stability. Adsorption experiments with Zn2Al-Met-LDHs showed that the residual arsenic in solution could be reduced below the regulation limit, and this adsorption process fitted Langmuir isotherm and the pseudo-second-order kinetics well. A remarkably high removal efficiency and the maximum adsorption capacity for As(III) were achieved, 96.7% and 94.1 mg/g, respectively, at 298 K. The desorption efficiency of As(III) from the arsenic-saturated Zn2Al-Met-LDHs (<8.7%), far less than that of As(V), promises a specific and reliable uptake of As(III) in sorts of solutions. More importantly, a complete and in-depth spectra analysis through FTIR, XPS and NMR was conducted to explain the excellent performance of Zn2Al-Met-LDHs in arsenic removal. Herein, two special chemical reactions were proposed as the dominant mechanisms, i.e., hydrogen bonding between the carboxyl group of the host Met and the hydroxyl group of As(III) or As(V), and the formation of a chelate ring between the guest As(III) and the S, N bidentate ligands of the intercalated Met in the LDHs.
authors.affiliation: Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China.
authors.forename: Liang
authors.initials: L
authors.lastname: Shen
authors.affiliation: Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China; Department of Environment Engineering, College of the Environment and Ecology, and The Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, Xiamen University, Xiamen, 361102, PR China; School of Environmental Science & Engineering, South University of Science and Technology of China, Shenzhen, 518055, PR China.
authors.forename: Xiuli
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Department of Environment Engineering, College of the Environment and Ecology, and The Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, Xiamen University, Xiamen, 361102, PR China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Environment Engineering, College of the Environment and Ecology, and The Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, Xiamen University, Xiamen, 361102, PR China.
authors.forename: Dun
authors.initials: D
authors.lastname: Fu
authors.affiliation: Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China; Department of Environment Engineering, College of the Environment and Ecology, and The Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, Xiamen University, Xiamen, 361102, PR China; College of Chemistry and Life Science, Quanzhou Normal University, Quanzhou, 362000, PR China.
authors.forename: Qingbiao
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Environment Engineering, College of the Environment and Ecology, and The Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, Xiamen University, Xiamen, 361102, PR China. Electronic address: yz3t@xmu.edu.cn.
authors.forename: Tong
authors.initials: T
authors.lastname: Ouyang
authors.affiliation: Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, PR China. Electronic address: wypp@xmu.edu.cn.
authors.forename: Yuanpeng
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D000536:Aluminum Hydroxide / Q000737:chemistry; D000596:Amino Acids / Q000737:chemistry*; D001149:Arsenates / Q000032:analysis* / Q000737:chemistry; D018053:Arsenites / Q000032:analysis* / Q000737:chemistry; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides / Q000737:chemistry*; D007700:Kinetics; D008715:Methionine / Q000737:chemistry; D008962:Models, Theoretical; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification / Q000379:methods; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D000596:Amino Acids; D001149:Arsenates; D018053:Arsenites; D006878:Hydroxides; D014874:Water Pollutants, Chemical; D017967:Zinc Compounds; D000536:Aluminum Hydroxide; D008715:Methionine; C052745:zinc hydroxide
keywords: Adsorption; As(III); As(V); Layered double hydroxides; Methionine