Department of Environmental Health Engineering, School of Health, Hamadan University of Medical Sciences, Hamadan, Iran.
J Hazard Mater. 2012 May 30;217-218:123-32. doi: 10.1016/j.jhazmat.2012.03.003. Epub 2012 Mar 23.
In this research work, pumice that is functionalized by the cationic surfactant, hexadecyltrimethyl ammonium (HDTMA), is used as an adsorbent for the removal of fluoride from drinking water. This work was carried out in two parts. The effects of HDTMA loading, pH (3-10), reaction time (5-60 min) and the adsorbent dosage (0.15-2.5 g L(-1)) were investigated on the removal of fluoride as a target contaminate from water through the design of different experimental sets in the first part. The results from this first part revealed that surfactant-modified pumice (SMP) exhibited the best performance at dose 0.5 g L(-1), pH 6, and it adsorbs over 96% of fluoride from a solution containing 10 mg L(-1) fluoride after 30 min of mixing time. The four linear forms of the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms model were applied to determine the best fit of equilibrium expressions. Apart from the regression coefficient (R(2)), four error functions were used to validate the isotherm and kinetics data. The experimental adsorption isotherm complies with Langmuir equation model type 1. The maximum amount of adsorption (Q(max)) was 41 mg g(-1). The kinetic studies indicated that the adsorption of fluoride best fitted with the pseudo-second-order kinetic type 1. Thermodynamic parameters evaluation of fluoride adsorption on SMP showed that the adsorption process under the selected conditions was spontaneous and endothermic. The suitability of SMP in defluoridation at field condition was investigated with natural groundwater samples collected from a nearby fluoride endemic area in the second part of this study. Based on this study's results, SMP was shown to be an affordable and a promising option for the removal of fluoride in drinking water.
在这项研究工作中，使用经过阳离子表面活性剂十六烷基三甲基铵（HDTMA）功能化的浮石作为吸附剂，用于去除饮用水中的氟化物。这项工作分两部分进行。在第一部分中，通过设计不同的实验装置，研究了 HDTMA 负载量、pH 值（3-10）、反应时间（5-60 分钟）和吸附剂用量（0.15-2.5 g/L）对氟化物去除的影响，氟化物是水中的目标污染物。结果表明，表面活性剂改性浮石（SMP）在剂量为 0.5 g/L、pH 值为 6 的条件下表现出最佳性能，在混合 30 分钟后，可从含有 10mg/L 氟化物的溶液中吸附超过 96%的氟化物。应用四种线性形式的朗缪尔、弗伦德利希、坦金和杜比宁-拉乌捷夫斯基等温线模型来确定平衡表达式的最佳拟合。除了回归系数（R(2)）之外，还使用了四个误差函数来验证等温线和动力学数据。实验吸附等温线符合朗缪尔方程模型类型 1。最大吸附量（Q(max)）为 41mg/g。动力学研究表明，氟化物的吸附最符合准二级动力学类型 1。对 SMP 上氟化物吸附的热力学参数评估表明，在所选择的条件下，吸附过程是自发的和吸热的。在本研究的第二部分中，用从附近氟中毒地区采集的天然地下水样本研究了 SMP 在野外除氟条件下的适用性。根据这项研究的结果，SMP 是一种具有成本效益且有前途的饮用水除氟选择。
