N_2和CO在5A分子筛上吸附的气相色谱研究

文中重新推导并简化了采用反相气相色谱法来测定吸附热力学参数的计算公式,并且在不同温度下,对N2和CO在4种5A分子筛上色谱保留时间进行了测定,对测定结果以推导公式为函数作线性回归,并且计算了吸附热力学参数ΔadH,ΔadS和ΔadG。结果表明,保留时间与1/T相关性很好,CO的吸附热随着分子筛Ca2+交换度的增加而增加,随着H+交换度的增加而减少,N2的吸附热则随着Ca2+交换度的增加变化不明显,随着H+交换度的增加而减少;CO和N2的吸附热在-25.36—-29.39 kJ/mol,4种分子筛对N2和CO的吸附熵在-80.01—-73.96J/(mol.K)和-72.13—-60.48 J/(mol.K),吸附G ibbs自由能变分别在-2.98—-4.77 kJ/mol和-9.82—-8.26 kJ/mol。

Adsorption thermodynamics of N2 and CO on 5A zeolite with gas chromatography

The formula for calculating the adsorption thermodynamic parameters using the inverse gas chromatography was deduced and simplified.By changing temperatures,some retention time of N_2 and CO on four kinds of molecular sieves was determined.Linear regression analysis of the retention time with 1/T was carried out based on the deduced formula,and the correlation was good.The adsorption thermodynamic parameters were calculated in according to the formula.The adsorption heat of CO and N_2 on molecular sieves ranges from-25.36 kJ/mol to-29.39 kJ/mol,and decreases with increasing the percentage of H+,and the adsorption heat of CO increases with increasing the percentage of Ca2+,whereas the adsorption heat of N_2 varies unobviously with increasing the percentage of Ca2+.The adsorption entropy and the Gibbs free energy of CO ranges from-72.13 J/(mol·K) to-60.48 J/(mol·K) and-9.82 kJ/mol to-8.26 kJ/mol,while the two variables of N_2 range from-80.01 J/(mol·K) to-73.96 J/(mol·K) and -2.98 kJ/mol to-4.77 kJ/mol,respectively.