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压实膨润土因其膨胀特性被用作高放射性核废料深地质处置工程的缓冲材料,膨润土的膨胀特性与其表面特性有关。对原始膨润土粉末以及被不同浓度的Na Cl溶液浸泡过的膨润土进行N2分子吸附实验,测得N2吸附等温线,对吸附等温线采用Frenkel-Halsey-Hill(FHH)方程和Neimark热力学方法计算表面分维,计算结果表明,采用两种方法计算的表面分维基本相同。膨润土的表面性质受Na Cl溶液浓度的影响较大,表面分维随Na Cl浓度的增加呈现出先增大后减小的趋势,这是由于浓度不同膨润土表面吸附的Na+量不同所引起的。
Compacted bentonite is used as a buffer for deep geological disposal of highly radioactive nuclear waste due to its swelling properties. The swelling behavior of bentonite is related to its surface properties. The N2 adsorption experiments were carried out on the original bentonite powder and bentonite soaked with NaCl solution with different concentrations. The N2 adsorption isotherm was measured. The Frenkel-Halsey-Hill (FHH) equation and the Neimark thermodynamic method were used to calculate the surface area The results show that the surface fractal dimension calculated by the two methods are basically the same. The surface properties of bentonite are greatly affected by the concentration of NaCl solution. The fractal dimension of the bentonite tends to increase firstly and then decrease with the increase of NaCl concentration, which is attributed to the different amount of Na + adsorbed on the surface of bentonite.