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纳米TiO2去除氟离子的性能

杨丽君,刘雪岩,姜鑫,李莹,常怀春,张蕾*   

  1. (辽宁大学化学院 沈阳 110036)
  • 收稿日期:2011-12-16 修回日期:2012-03-08 出版日期:2012-11-10 发布日期:2012-11-10
  • 通讯作者: 张蕾，教授; Tel:024-62207816; Fax:024-62202380; E-mail:zhanglei63@126.com; 研究方向：功能材料在稀贵金属分离富集中的应用；环境污物分析、监控及去除研究；环境友好材料制备技术及其应用
  • 基金资助:
    国家自然科学基金(51178212)辽宁省自然科学基金（201102082）资助项目

Properties of Nano-TiO2 for Removal of Fluorine Ions

YANG Lijun, LIU Xueyan, JIANG Xin, LI Ying, CHANG Huaichun, ZHANG Lei*   

  1. (College of Chemistry,Liaoning University,Shenyang 110036,China)
  • Received:2011-12-16 Revised:2012-03-08 Published:2012-11-10 Online:2012-11-10
  • Contact: ZHANG Lei

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摘要： 研究了锐钛型纳米TiO2吸附剂对氟离子的吸附行为，考察了吸附平衡时间、温度、溶液的pH值等因素对吸附过程的影响。 结果表明，纳米TiO2对氟离子的吸附在2.0 min基本达到平衡，在pH值2.0~10.0范围内，吸附率大于97%；吸附的氟离子可用0.1 mol/L NaOH溶液洗脱，3.0 min基本达到解析平衡，解析率能达到96%；该吸附过程符合准二级反应动力学模型，其反应的表观活化能(Ea)为6.85 kJ/mol；颗粒内扩散过程为吸附控制步骤，但不是唯一的控制步骤，同时还受液膜扩散的影响；吸附过程符合Langmuir、D-R等温模型，常温下纳米TiO2对氟离子的平均吸附能为4.26 kJ/mol。 吸附反应的ΔG0＜0，焓变ΔH0＞0，说明该吸附过程是自发的吸热反应。 共存阴离子HCO-3和PO3-4对氟离子的吸附有影响。 纳米TiO2在动态和静态吸附实验中的除氟效果相近。

关键词: 氟离子, 纳米TiO2, 吸附, 动力学, 热力学

Abstract: Anatase titanium dioxide nanoparticles were employed for the adsorption of fluoride ions from aqueous solution. The process was studied in details by varying the pH value, adsorption time and temperature. The results showed that equilibrium was reached within 2.0 min at room temperature. The adsorption efficiency was over 97% at pH 2.0~10.0. Adsorbed fluoride ions were desorbed with 0.1 mol/L NaOH within 3.0 min, while the desorption efficiency could be up to 96%. The kinetic experimental data properly correlate with the second-order kinetic model. The apparent activation energy was calculated to be 6.85 kJ/mol. The overall rate process is mainly controlled by the intraparticle diffusion, while the boundary layer resistance cannot be ignored. The adsorption data could be well interpreted by the Langmuir and Dubinin-Radushkevich adsorption isotherms. The mean energy of adsorption was 4.26 kJ/mol at room temperature. The results show that ΔH0＞0 and ΔG0＜0 for the adsorption reaction, indicating that the adsorption process is a spontaneous and endothermic reaction. The co-existed ions such as HCO-3 and PO3-4, had greater effects on adsorption of fluoride ions. Removal efficiency of nano-TiO2 for fluoride ions obtained by dynamic adsorption is close to that obtained by the static adsorption.

Key words: fluorine ions, nano-TiO2, adsorption, dynamics, thermodynamics

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