Tang Qingzi, Duan Tongdan, Li Peng, Zhang Ping, Wu Daishe
Key Laboratory of Poyang Lake Environment and Resource Utilization, School of Environmental and Chemical Engineering, Ministry of Education, Nanchang University, Nanchang, China.
Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia.
Front Chem. 2018 Apr 11;6:104. doi: 10.3389/fchem.2018.00104. eCollection 2018.
In this work, the potential of a novel hydroxyapatite decorated with carbon nanotube composite (CNT-HAP) for fluoride removal was investigated. The synthesized CNT-HAP composite was systematically characterized by X-ray diffraction(XRD), Fourier Transform infrared spectroscopy(FTIR), scanning electron microscope (SEM) and Brunauer-Emmett-Teller(BET). Batch adsorption experiments were conducted to investigate the defluorination capacity of CNT-HAP. The CNT-HAP composite has a maximum adsorption capacity of 11.05 mg·g for fluoride, and the isothermal adsorption data were fitted by the Freundlich model to calculate the thermodynamic parameters. Thermodynamic analysis implies that the adsorption of fluoride on CNT-HAP is a spontaneous process. Furthermore, the adsorption of fluoride follows pseudo-second-order model. The effects of solution pH, co-existing anions and reaction temperature on defluorination efficiency were examined to optimize the operation conditions for fluoride adsorption. It is found that the optimized pH-value for fluoride removal by CNT-HAP composite is 6. In addition, among five common anions studied in this work, the presence of [Formula: see text] and [Formula: see text] could considerably affect the fluoride removal by CNT-HPA in aqueous media. Finally, the underlying mechanism for the fluoride removal by CNT-HAP is analyzed, and an anion exchange process is proposed.
在本研究中，对一种新型的碳纳米管修饰羟基磷灰石复合材料（CNT-HAP）去除氟化物的潜力进行了研究。通过X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）和布鲁诺尔-埃米特-泰勒（BET）法对合成的CNT-HAP复合材料进行了系统表征。进行了批量吸附实验以研究CNT-HAP的除氟能力。CNT-HAP复合材料对氟化物的最大吸附容量为11.05 mg·g，等温吸附数据用弗伦德利希模型拟合以计算热力学参数。热力学分析表明，氟化物在CNT-HAP上的吸附是一个自发过程。此外，氟化物的吸附遵循准二级模型。研究了溶液pH值、共存阴离子和反应温度对除氟效率的影响，以优化氟化物吸附的操作条件。发现CNT-HAP复合材料去除氟化物的最佳pH值为6。此外，在本研究中考察的五种常见阴离子中，[公式：见原文]和[公式：见原文]的存在会显著影响CNT-HPA在水介质中对氟化物的去除。最后，分析了CNT-HAP去除氟化物的潜在机制，并提出了阴离子交换过程。
