反气相色谱法测定燃料乙醇专用吸附剂对水和乙醇的吸附

利用反气相色谱法研究了燃料乙醇专用吸附剂在60～130?℃范围内对水和乙醇的吸附，并用环境扫描电镜对吸附剂的性质进行了表征。由气相色谱的保留时间计算出水和乙醇的分离因子和吸附剂吸附水、乙醇的吉布斯自由能变化（ΔG_s）、吸附焓变（ΔH_s）等热力学参数。实验结果表明，水和乙醇的吸附焓变分别为-37.41、-4.59kJ/mol，属于物理吸附过程。吸附的ΔG_s、ΔH_s均为负值,说明该吸附过程是自发的放热过程，低温度有利于吸附。吸附剂对水的吸附比乙醇强烈得多，可以选择性吸附水分,达到脱水的目的。

An inverse gas chromatography method for determining the adsorption of water and ethanol on fuel ethanol special adsorbent

Adsorption of water and ethanol on fuel ethanol special adsorbent has been studied at 60～130℃ using inverse gas chromatography (IGC). The performance of the adsorbent was also studied by environmental scanning electron microscopy (ESEM). From the chromatographic retention data it was possible to calculate the separation factors for the two solutes and to obtain values for thermodynamic parameters such as the Gibbs free energy (ΔG_s) and the enthalpy (ΔH_s) of adsorption of water and ethanol on the fuel ethanol special adsorbent. The values of the enthalpy of adsorption calculated from retention data are -37.41kJ/mol for water and -4.59kJ/mol for ethanol. Adsorption of both water and ethanol was shown to take place by physical adsorption. Low temperatures were found to favor adsorption, indicative of an exothermic process. The affinity of the adsorbent for water is greater than that for ethanol, and this allows the material to be used for effective drying of fuel ethanol.