天然钠长石和钾长石对水溶液中氟吸附性能的研究  

Investigations of the adsorption of fluoride on natural sodium feldspar and potassium feldspar in aqueous solution

作　　者：张为 任亚楠 赵晓琳 颜婷珪 孙琦 ZHANG Wei;REN Ya-nan;ZHAO Xiao-lin;YAN Ting-gui;SUN Qi(Research Center of Karst Ecological Civilization,Guizhou Normal University,Guiyang 550025,China;School of Chemistry and Chemical Engineering,Guizhou University,Guiyang 550025,China)

机构地区：[1]贵州师范大学喀斯特生态文明研究中心,贵州贵阳550025 [2]贵州大学化学与化工学院,贵州贵阳550025

出　　处：《云南大学学报（自然科学版）》2020年第5期977-984,共8页Journal of Yunnan University(Natural Sciences Edition)

基　　金：国家自然科学基金(21808045);贵州省科技计划项目(黔科合基础[2019]1230号,黔科合基础[2019]1066号)。

摘　　要：通过批实验研究了pH、初始氟离子浓度、反应时间和离子强度等因素对天然钠长石和钾长石吸附氟的影响.结果显示,钾长石和钠长石的pHpzc分别为8.0和6.5,说明酸性条件更有利于长石矿物对氟的吸附,其中吸附反应最佳pH为3.初始氟离子浓度增大能够显著促进长石对氟的吸附,pH=2时,随着初始氟质量浓度从20 mg·L^-1增加到310 mg·L^-1,钠长石对氟的吸附率从1.9%增加到29.4%,钾长石对氟的吸附率从2.8%增加到40.2%.长石对氟的吸附过程可以使用准二级动力学模型和Freundlich等温吸附模型所描述,离子强度对氟的吸附能力没有大的影响,说明吸附过程主要受化学吸附的控制.由于钾长石更大的比表面积和更多的吸附点位,酸性条件下钾长石对氟的吸附能力比钠长石更大.The effects of pH, initial fluoride ion concentration, reaction time and ionic strength on the adsorption of fluoride on natural sodium feldspar and potassium feldspar were studied through batch experiments.The results show that the pHpzc of potassium feldspar and sodium feldspar are 8.0 and 6.5, respectively, which indicating the acidic conditions are more conducive to the adsorption of fluoride. The optimal pH for the fluoride adsorption reaction is 3. The increase of initial fluoride ion concentration can significantly promote the adsorption of fluoride on feldspar. At pH = 2, as the initial fluoride concentration increases from 20 mg·L-1 to 310 mg·L-1, the adsorption rate of fluoride on sodium feldspar was increased from 1.9% to 29.4%, and that on potassium feldspar increased from 2.8% to 40.2%. The adsorption process of fluoride on feldspar can be described by the pseudo second-order kinetic model and the Freundlich isotherm adsorption model. The ionic strength has no significant effect on the adsorption capacity of fluorine. These results indicated that the adsorption process is mainly controlled by chemical adsorption. Because potassium feldspar has a greater specific surface area and more adsorption sites, potassium feldspar has a greater adsorption capacity for fluoride than sodium feldspar under the same acidic conditions.

关 键 词：钠长石 钾长石 氟 吸附行为 批实验 

分 类 号：P592[天文地球—地球化学]