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Precise Adsorption Behavior and Mechanism of Ni(II) ions on Nano‐Hydroxyapatite
Author(s) -
Zhang Jun,
Wang Deping,
Zhou Jun,
Yao Aihua,
Huang Wenhai
Publication year - 2010
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143010x12609736966405
Subject(s) - adsorption , dissolution , precipitation , fourier transform infrared spectroscopy , crystal (programming language) , langmuir adsorption model , ion , transmission electron microscopy , chemical engineering , specific surface area , materials science , phase (matter) , chemistry , nanotechnology , organic chemistry , catalysis , physics , meteorology , computer science , engineering , programming language
The goal of this study was to synthesize use of hydroxyapatite as a high‐efficiency adsorbent for Ni(II) ions, and to study its adsorption behavior. Three tests— Fourier‐transform infrared spectroscopy, transmission electron microscopy, and Brunauer‐Emmett‐Teller —were carried out to determine the chemical functionality of the hydroxyapatite powders, to observe its crystal morphology, and to measure the specific surface area. Results indicate that proves the n‐HA synthesized by chemical precipitation is an effective adsorbent for the removal of Ni(II) ions from water solution. The synthesized, needle‐like nano‐hydroxyapatite (n‐HA) have a uniform average size of 31.9 × 21.3nm, a large specific surface area (135 m 2 /g), and typically is a weak crystal with a broad pore distribution. The adsorption isotherm shows the Langmuir model is applicable only when the initial Ni 2+ concentration is lower than 0.1 mol/L. Multilayer adsorption was attributed to uneven pore distribution that occurred at higher Ni 2+ concentration. The adsorption of Ni 2+ onto n‐HA was attributed to electrostatic attraction, ion exchange, and dissolution‐precipitation reaction. As the result, Ni 2+ substitutes Ca 2+ and binds with the oxygen atom on the surface, which resulted from the change in crystal‐phase composition and in the binding energy of surface elements of n‐HA before and after adsorption.