Fluorine effects on U(VI) sorption by hydroxyapatite
Fluorine effects on U(VI) sorption by hydroxyapatite
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DOI：
10.1016/j.cej.2015.12.045
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发表时间：
2016-03
影响因子：
15.1
通讯作者：
Jun Liu;Changsong Zhao;Zhibin Zhang;J. Liao;Yunhai Liu;Xiaohong Cao;Jijun Yang;Yuanyou Yang
中科院分区：
文献类型：
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作者：
Jun Liu;Changsong Zhao;Zhibin Zhang;J. Liao;Yunhai Liu;Xiaohong Cao;Jijun Yang;Yuanyou Yang
研究了羟基磷灰石（HAp）的氟掺杂和氟离子浓度对其吸附U（VI）的影响。结果表明，掺氟羟基磷灰石和羟基磷灰石对U（VI）的吸附在75 min时达到平衡，且在较低的pH初始值（3. 5）时达到最大吸附量。准二级动力学模型描述的吸附过程，而Langmuir模型和吸附等温线过程表明，该机制是化学吸附在一个均匀的材料。计算的热力学参数表明，U（VI）在材料上的吸附是一个自发的吸热过程。特别是，我们确定，溶液中的高浓度的氟离子显着降低U（VI）的吸附能力，而氟掺杂也降低了U（VI）的吸附HAp。然而，氟掺杂增加了HAp在酸性条件下的稳定性。此外，UO 2F+和UO 2F 2（aq）不太可能通过F原子吸附到吸附剂上，因为铀酰离子的氧原子或铀原子已经与F原子键合，当溶液中含有非常高浓度的铀时，F−可能首先形成U-F络合物，而不是交换OH−。本研究报告的发现有助于促进使用HAp和其他材料从溶液中去除铀，特别是从环境中的氟铀放射性废水中去除铀。
In this study, the effects of fluorine doping of HAp and fluoride ions concentration on the sorption behavior of U(VI) by hydroxyapatite (HAp) were investigated. The results demonstrated that the sorption equilibrium of U(VI) on fluorine-doped hydroxyapatite and hydroxyapatite was reached by 75 min of contact time, and the maximum sorption of U(VI) was achieved at a low pHinitialvalue of 3. The pseudo-second order model described the kinetic sorption processes, whereas the Langmuir model and the sorption isotherm process indicated that the mechanism was chemisorption on a homogeneous material. The calculated thermodynamic parameters suggested the sorption of U(VI) on materials was a spontaneous and endothermic process. In particular, we determined that a high concentration of fluorine ions in solution markedly decreased the U(VI) sorption capacity, whereas fluorine doping also lowered the U(VI) sorption by HAp. However, fluorine doping increased the stability of HAp in acidic conditions. In addition, it is unlikely that UO2F+and UO2F2(aq)species adsorbed via F atoms to the adsorbents, as the oxygen atoms or uranium atoms of uranyl ions are already bonded to F atoms, and F−is likely to form U–F complexes first rather than exchange for OH−when the solution contain uranium with very high concentration. The findings reported in this study aid in facilitating the removal of uranium from solutions using HAp and other materials, especially from fluorine–uranium radioactive wastewater in the environment.