title: Wide pH range for fluoride removal from water by MHS-MgO/MgCO₃ adsorbent: kinetic, thermodynamic and mechanism studies.
abstract: A novel environment friendly adsorbent, micro-nano hierarchical structured flower-like MgO/MgCO3 (MHS-MgO/MgCO3), was developed for fluoride removal from water. The adsorbent was characterized and its defluoridation properties were investigated. Adsorption kinetics fitted well the pseudo-second-order model. Kinetic data revealed that the fluoride adsorption was rapid, more than 83-90% of fluoride could be removed within 30 min, and the adsorption equilibrium was achieved in the following 4 h. The fluoride adsorption isotherm was well described by Freundlich model. The maximum adsorption capacity was about 300 mg/g at pH=7. Moreover, this adsorbent possessed a very wide available pH range of 5-11, and the fluoride removal efficiencies even reached up to 86.2%, 83.2% and 76.5% at pH=11 for initial fluoride concentrations of 10, 20 and 30 mg/L, respectively. The effects of co-existing anions indicated that the anions had less effect on adsorption of fluoride except phosphate. In addition, the adsorption mechanism analysis revealed that the wide available pH range toward fluoride was mainly resulted from the exchange of the carbonate and hydroxyl groups on the surface of the MHS-MgO/MgCO3 with fluoride anions.
authors: Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, PR China; Nano-Materials and Environmental Detection Laboratory, Hefei Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China.
authors: Kaisheng
authors: K
authors: Zhang
authors: Nano-Materials and Environmental Detection Laboratory, Hefei Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China.
authors: Shibiao
authors: S
authors: Wu
authors: Nano-Materials and Environmental Detection Laboratory, Hefei Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China.
authors: Xuelong
authors: X
authors: Wang
authors: Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, PR China; Nano-Materials and Environmental Detection Laboratory, Hefei Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China.
authors: Junyong
authors: J
authors: He
authors: Nano-Materials and Environmental Detection Laboratory, Hefei Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China.
authors: Bai
authors: B
authors: Sun
authors: Nano-Materials and Environmental Detection Laboratory, Hefei Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China.
authors: Yong
authors: Y
authors: Jia
authors: Nano-Materials and Environmental Detection Laboratory, Hefei Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China.
authors: Tao
authors: T
authors: Luo
authors: Nano-Materials and Environmental Detection Laboratory, Hefei Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China.
authors: Fanli
authors: F
authors: Meng
authors: Nano-Materials and Environmental Detection Laboratory, Hefei Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China.
authors: Zhen
authors: Z
authors: Jin
authors: Nano-Materials and Environmental Detection Laboratory, Hefei Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China.
authors: Dongyue
authors: D
authors: Lin
authors: Nano-Materials and Environmental Detection Laboratory, Hefei Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China.
authors: Wei
authors: W
authors: Shen
authors: Nano-Materials and Environmental Detection Laboratory, Hefei Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China. Electronic address: ltkong@iim.ac.cn.
authors: Lingtao
authors: L
authors: Kong
authors: Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, PR China; Nano-Materials and Environmental Detection Laboratory, Hefei Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China.
authors: Jinhuai
authors: J
authors: Liu
mesh_terms: D000327:Adsorption; D005459:Fluorides / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000737:chemistry*; D008277:Magnesium Oxide / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods; D014961:X-Ray Diffraction
chemical_list: D014874:Water Pollutants, Chemical; C005479:magnesium carbonate; D008277:Magnesium Oxide; D008274:Magnesium; D005459:Fluorides
keywords: Carbonate; Fluoride; Ion exchange; Kinetics; MgO/MgCO(3)