钛硅酸钠（Na2Ti2O3SiO4·2H2O）对Cs的吸附热力学分析

钛硅酸钠(Crystalline Sillicotitanate, CST)对铯（Cs）的吸附热力学分析是研究钛硅酸钠吸附铯机理的重要途径之一。本工作通过研究不同温度下CST与不同浓度CsNO₃溶液反应，测定反应前后Cs⁺的浓度变化，得到了一系列参数。结果显示，不同的反应温度对应不同的饱和吸附量，当温度为298.15 、313.15和328.15 K时，饱和吸附量分别为212.8、217.4和232.6 mg/g。分别用Langmuir方程和Freundlich方程对实验数据进行拟合，结果表明，此吸附过程更符合Langmuir等温吸附。在不考虑温度对吸附焓和吸附熵影响的前提下，计算得到吸附焓ΔH=21.28 kJ/mol，ΔS=89.18 J/K/mol以及ΔG<0。以上结果表明，CST对Cs的吸附过程是一个自发进行、既有物理吸附又有化学吸附的吸热反应。

Thermodynamics Analysis of Cesium Adsorption on Na_2Ti_2O_3SiO_4·2H_2O

Thermodynamical analysis of cesium adsorption on CST is considered to be one of the important approaches in studying the adsorption mechanism of cesium on CST.A series of parameters were obtained by measuring the change of the Cs＋ ion concentration before and after the sorption.The CST sorption experiments were conducted with the CsNO3 solution at different concentrations and temperatures.The saturation adsorption was found to be 212.8,217.4 and 232.6 mg/g at 298.15,313.15 and 328.15 K,respectively.The experimental data were fitted with the Langmuir model or the Freundlich model.The results showed that the Langmuir isotherm better fits this adsorption process.With the assumption that the adsorption enthalpy and adsorption entropy are independent of the temperature,the adsorption enthalpy and entropy were calculated to be 21.28 kJ/mol and 89.18 J·K-1·mol-1,respectively,with a negative adsorption free energy.The results indicated that the adsorption of cesium on CST is a spontaneous and endothermic process,with both physical and chemical adsorptions involved.