烷基铵在低层电荷蒙脱石上的等温吸附

Isothermal adsorption of alkylammonium in middle charged montmorillonite

蒙脱石/烷基铵复合物是一种高附加值的矿物复合材料,复合物中烷基铵的吸附量与其凝胶性能密切相关。以山东某低层电荷的膨润土为原料,在提纯、钠化的基础上,系统研究了80℃恒温条件下十八烷基三甲基铵(OTC)、十六烷基三甲基铵(CTAC)及十四烷基三甲基铵(TTAC)在蒙脱石上的等温吸附特性。研究结果表明,在80℃恒温交换体系中,当烷基铵的用量较高时,3种烷基铵在蒙脱石上均呈现超量吸附,且饱和吸附量都随着碳链长度的增加而增加。3种烷基铵在蒙脱石上的等温吸附特性均与Modified Lang-muir模型拟合较好,吸附数据曲线与Modified Lang-muir模型拟合度分别为0.992、0.986和0.979,相应的蒙脱石对烷基铵饱和吸附量分别是2.101、2.042和1.760mmol/g,与实验数据吻合较好。

Montmorillonite/alkylammonium compound is a mineral composites with high added value,the adsorption amount was closely related to the gel performance of the composite.In this paper,on base of purification and sodium modification of the lower charged bentonite from Shandong Province,at 80℃,adsorption characteristics of octadecyl trimethyl ammonium（OTAC）,cetyl trimethylammonium（CTAC） and tetradecyl trimethyl ammonium（TTAC） in montmorillonite are systematically researched.The research results are as the following： at a higher dosage in the organic system,all the three alkylamines exhibit excessive adsorption characteristics in montmorillonite interlayers,the saturated adsorption amount increases with he length of the carbon chain in the alkylammonium.The isothermal adsorption of the three alkylamines are fitted well with modified langmuir models,the fitting degree of the three alkylamines are respectively 0.992,0.986,0.977.Correspondingly the saturated extent of adsorption of OTAC,CTAC and TTAC are 2.101,2.042,1.760mmol/g,which fit well with the experimental data.