Dissolution and Solubility Product of Cd-Fluorapatite [Cd5(PO4)3F] at pH of 2–9 and 25–45°C

Dissolution of the synthetic cadmium fluorapatite [Cd5(PO4)3F] at 25°C, 35°C, and 45°C was experimentally examined in HNO3 solution, pure water, and NaOH solution. The characterization results confirmed that the cadmium fluorapatite nanorods used in the experiments showed no obvious variation after...

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Main Authors: Ju Lin, Zongqiang Zhu, Yinian Zhu, Huili Liu, Lihao Zhang, Zhangnan Jiang
Format: Article
Language:English
Published: Wiley 2018-01-01
Series:Journal of Chemistry
Online Access:http://dx.doi.org/10.1155/2018/3109047
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author Ju Lin
Zongqiang Zhu
Yinian Zhu
Huili Liu
Lihao Zhang
Zhangnan Jiang
author_facet Ju Lin
Zongqiang Zhu
Yinian Zhu
Huili Liu
Lihao Zhang
Zhangnan Jiang
author_sort Ju Lin
collection DOAJ
description Dissolution of the synthetic cadmium fluorapatite [Cd5(PO4)3F] at 25°C, 35°C, and 45°C was experimentally examined in HNO3 solution, pure water, and NaOH solution. The characterization results confirmed that the cadmium fluorapatite nanorods used in the experiments showed no obvious variation after dissolution. During the dissolution of Cd5(PO4)3F in HNO3 solution (pH = 2) at 25°C, the fluoride, phosphate, and cadmium ions were rapidly released from solid to solution, and their aqueous concentrations had reached the highest values after dissolution for <1 h, 1440 h, and 2880 h, respectively. After that, the total dissolution rates declined slowly though the solution Cd/P molar ratios increased incessantly from 1.55∼1.67 to 3.18∼3.22. The solubility product for Cd5(PO4)3F (Ksp) was determined to be 10−60.03 (10−59.74∼10−60.46) at 25°C, 10−60.38 (10−60.32∼10−60.48) at 35°C, and 10−60.45 (10−60.33∼10−60.63) at 45°C. Based on the log Ksp values obtained at an initial pH of 2 and 25°C, the Gibbs free energy of formation for Cd5(PO4)3F (ΔGf0) was calculated to be −4065.76 kJ/mol (−4064.11∼−4068.23 kJ/mol). The thermodynamic parameters for the dissolution process were computed to be 342515.78 J/K·mol, −85088.80 J/mol, −1434.91 J/K·mol, and 2339.50 J/K·mol for ΔG0, ΔH0, ΔS0, and ΔCp0, correspondingly.
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institution Kabale University
issn 2090-9063
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language English
publishDate 2018-01-01
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series Journal of Chemistry
spelling doaj-art-7a8bdd244d6f40a9b2f183426f8c32402025-02-03T05:50:33ZengWileyJournal of Chemistry2090-90632090-90712018-01-01201810.1155/2018/31090473109047Dissolution and Solubility Product of Cd-Fluorapatite [Cd5(PO4)3F] at pH of 2–9 and 25–45°CJu Lin0Zongqiang Zhu1Yinian Zhu2Huili Liu3Lihao Zhang4Zhangnan Jiang5College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, ChinaGuangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, ChinaCollege of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, ChinaCollege of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, ChinaGuangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, ChinaCollege of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, ChinaDissolution of the synthetic cadmium fluorapatite [Cd5(PO4)3F] at 25°C, 35°C, and 45°C was experimentally examined in HNO3 solution, pure water, and NaOH solution. The characterization results confirmed that the cadmium fluorapatite nanorods used in the experiments showed no obvious variation after dissolution. During the dissolution of Cd5(PO4)3F in HNO3 solution (pH = 2) at 25°C, the fluoride, phosphate, and cadmium ions were rapidly released from solid to solution, and their aqueous concentrations had reached the highest values after dissolution for <1 h, 1440 h, and 2880 h, respectively. After that, the total dissolution rates declined slowly though the solution Cd/P molar ratios increased incessantly from 1.55∼1.67 to 3.18∼3.22. The solubility product for Cd5(PO4)3F (Ksp) was determined to be 10−60.03 (10−59.74∼10−60.46) at 25°C, 10−60.38 (10−60.32∼10−60.48) at 35°C, and 10−60.45 (10−60.33∼10−60.63) at 45°C. Based on the log Ksp values obtained at an initial pH of 2 and 25°C, the Gibbs free energy of formation for Cd5(PO4)3F (ΔGf0) was calculated to be −4065.76 kJ/mol (−4064.11∼−4068.23 kJ/mol). The thermodynamic parameters for the dissolution process were computed to be 342515.78 J/K·mol, −85088.80 J/mol, −1434.91 J/K·mol, and 2339.50 J/K·mol for ΔG0, ΔH0, ΔS0, and ΔCp0, correspondingly.http://dx.doi.org/10.1155/2018/3109047
spellingShingle Ju Lin
Zongqiang Zhu
Yinian Zhu
Huili Liu
Lihao Zhang
Zhangnan Jiang
Dissolution and Solubility Product of Cd-Fluorapatite [Cd5(PO4)3F] at pH of 2–9 and 25–45°C
Journal of Chemistry
title Dissolution and Solubility Product of Cd-Fluorapatite [Cd5(PO4)3F] at pH of 2–9 and 25–45°C
title_full Dissolution and Solubility Product of Cd-Fluorapatite [Cd5(PO4)3F] at pH of 2–9 and 25–45°C
title_fullStr Dissolution and Solubility Product of Cd-Fluorapatite [Cd5(PO4)3F] at pH of 2–9 and 25–45°C
title_full_unstemmed Dissolution and Solubility Product of Cd-Fluorapatite [Cd5(PO4)3F] at pH of 2–9 and 25–45°C
title_short Dissolution and Solubility Product of Cd-Fluorapatite [Cd5(PO4)3F] at pH of 2–9 and 25–45°C
title_sort dissolution and solubility product of cd fluorapatite cd5 po4 3f at ph of 2 9 and 25 45°c
url http://dx.doi.org/10.1155/2018/3109047
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