Electrosorption of fluoride on TiO2-loaded activated carbon in water
Electrosorption of fluoride on TiO2-loaded activated carbon in water
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DOI：
10.1016/j.colsurfa.2016.05.020
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发表时间：
2016-08
期刊：
影响因子：
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通讯作者：
Peng Wu;L. Xia;Min Dai;Lili Lin;Shaoxian Song
中科院分区：
文献类型：
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作者：
Peng Wu;L. Xia;Min Dai;Lili Lin;Shaoxian Song
本文研究了负载型TiO 2活性炭（Ti-AC）电吸附水中氟离子的过程，旨在开发一种新的除氟工艺。采用溶胶-凝胶法实现了活性炭负载TiO 2。实验结果表明，Ti-AC的电吸附容量是原来AC的两倍。吸附符合Langmuir吸附等温式，最大吸附容量为157.8 μmol/g，吸附动力学符合准二级动力学模型。pH研究表明，Ti-AC在pH 6 ~ 9范围内具有较好的电吸附性能。通过X射线光电子能谱和傅里叶变换红外光谱，发现氟化物通过配体交换取代了−OH基团而存在于Ti-AC表面。吸附机理可能是由于氟离子首先通过电吸附进入活性炭的双电层，使电极表面附近的氟离子平衡浓度大大增加，随后氟离子在活性炭表面发生化学吸附，从而大大提高了吸附容量。
In this work the electrosorption of fluoride ions on TiO2-loaded activated carbon (Ti-AC) in water has been studied, in order to develop a novel process to remove fluoride from water. The loading of TiO2on activated carbon (AC) was realized with sol–gel method. The experimental results have shown that the capacity of the electrosorption on the Ti-AC was two folds of that on the original AC. The sorption fitted to the Langmuir isotherm with the maximum capacity of 157.8 μmol/g, and the sorption kinetics followed pseudo-second-order model. The pH study showed the adsorption capacity of Ti-AC by electrosorption had a good performance at pH range of 6–9. By means of X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy, it was found that the fluoride existed on the Ti-AC surfaces through ligand exchange to replace the −OH group. The mechanism of the sorption might be attributed to that fluoride first entered the electric double layer of the AC through electrosorption and led to the great increase of fluoride equilibrium concentration near the electrode surfaces, followed by the chemisorption of fluoride on the surfaces, which would greatly improve the sorption capacity.