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Phosphate uptake behavior and mechanism analysis of facilely synthesized nanocrystalline Zn‐Fe layered double hydroxide with chloride intercalation
Author(s) -
Yang Bokai,
Liu Dongfang,
Lu Jianbo,
Meng Xianrong,
Sun Yu
Publication year - 2018
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.6391
Subject(s) - chemistry , adsorption , freundlich equation , intercalation (chemistry) , zeta potential , hydroxide , langmuir , x ray photoelectron spectroscopy , fourier transform infrared spectroscopy , coprecipitation , inorganic chemistry , infrared spectroscopy , langmuir adsorption model , nuclear chemistry , materials science , chemical engineering , organic chemistry , engineering , nanotechnology , nanoparticle
Zn‐Fe layered double hydroxide with chloride intercalation (ZFCL) was synthesized by a coprecipitation method at room temperature. ZFCL was characterized by N 2 adsorption‐desorption isotherms, X‐ray diffraction, scanning electron microscope, Zeta‐sizer analyzer, X‐ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The results showed that ZFCL had large surface area and layered structure. The maximum adsorption capacity of ZFCL was 150.6 mg/g at 25°C. That was higher than most other adsorbent which were reported. The kinetic data were described better by the pseudo‐second‐order adsorption kinetic rate model. The adsorption isotherm on the adsorbent was described by Langmuir, Freundlich, and Sips models at pH 6 and followed the fitting order: Sips >Freundlich>Langmuir. Thermodynamic analyses indicated that the phosphate adsorption on ZFCL was endothermic and spontaneous in nature. The sequence of coexisting cations and anions competing with phosphate was Ca 2+ > Mg 2+ > Na + and SO 4 2− > NO 3 − > Cl − . ZFCL can be regenerated by the sequential use of NaOH and ZnCl 2 . The adsorption capacity remained high as 108.6 mg/g after regeneration of 3 times. The results of zeta potential, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy analyses indicated that the phosphate adsorption mechanisms involved ion exchange, Zn 3 (PO 4 ) 2 precipitation, and the formation of inner‐sphere complex via replacement of surface hydroxyl groups by phosphate.