Department of Civil and Materials Engineering, University of Illinois at Chicago, 842 West Taylor Street, Chicago, IL 60607-7023, USA.
J Colloid Interface Sci. 2013 Mar 15;394:419-27. doi: 10.1016/j.jcis.2012.11.063. Epub 2012 Dec 19.
Adsorption of fluoride from water onto titanium dioxide (TiO(2)) powder was investigated. The sorbent was crystalline TiO(2) composed of mostly anatase with a specific surface area of 56 m(2)/g. Adsorption kinetics and isotherm experiments were performed using an aqueous solution with bicarbonate alkalinity representative of natural waters. Adsorption kinetics data showed that maximum adsorption of fluoride occurred within 3h, following a pseudo-second order kinetics model. Adsorption isotherm data followed the Langmuir equation, indicating favorable adsorption of fluoride onto TiO(2), while results from the Dubinin-Radushkevich model are indicative of physical adsorption of fluoride. Adsorption of fluoride increased with decreasing solution pH. Maximum adsorption of fluoride occurred within the pH range of 2-5, while approximately 75% of maximum adsorption was obtained in the pH range of 7-8 with rapidly declining adsorption above pH 9. The pH(pzc) data for TiO(2) indicated the preferred adsorption of fluoride onto the acidic surface of TiO(2). Higher bicarbonate concentrations in solution increased the solution pH which was conducive to a decrease in adsorption of fluoride onto the surface of TiO(2) at higher pH. Overall, the solution pH was the main factor controlling the uptake of fluoride by TiO(2).
研究了将氟从水中吸附到二氧化钛 (TiO(2)) 粉末上。该吸附剂是由主要为锐钛矿组成的结晶 TiO(2)，比表面积为 56m(2)/g。使用具有天然水中代表性的碳酸氢盐碱度的水溶液进行了吸附动力学和等温线实验。吸附动力学数据表明，在 3 小时内发生了氟的最大吸附，遵循拟二级动力学模型。吸附等温线数据符合朗缪尔方程，表明氟在 TiO(2)上的吸附有利，而杜宾宁-拉什科夫斯基模型的结果表明氟的物理吸附。氟的吸附随溶液 pH 的降低而增加。氟的最大吸附发生在 pH 2-5 的范围内，而在 pH 7-8 的范围内，氟的最大吸附量约为 75%，pH 超过 9 时吸附迅速下降。TiO(2)的 pH(pzc)数据表明，氟优先吸附在 TiO(2)的酸性表面上。溶液中较高的碳酸氢盐浓度会增加溶液 pH，这有利于在较高 pH 时减少氟在 TiO(2)表面上的吸附。总的来说，溶液 pH 是控制 TiO(2 对氟的摄取的主要因素。
