Water adsorption characteristics of MCM-41 post-modified by Al grafting and cations doping: equilibrium and kinetics study

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• 作者：Hongyin Chen ; Jing Ding ; Weilong Wang ; Xiaolan Wei ; Jianfeng Lu
• 关键词：Water adsorption ; Equilibrium and kinetics ; MCM ; 41 ; Post modification ; Transient uptake rate
• 刊名：Adsorption
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：23
• 期：1
• 页码：113-120
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Industrial Chemistry/Chemical Engineering; Surfaces and Interfaces, Thin Films; Engineering Thermodynamics, Heat and Mass Transfer;
• 出版者：Springer US
• ISSN：1572-8757
• 卷排序：23

文摘

Post modification methods were used to synthesis MCM-41 with different pore sizes, modified by Al grafting and cation doping. Water adsorption characteristics were measured by dynamic water vapor adsorption and analyzed regarding equilibrium and kinetics. Results showed that Al grafting and cations doping modifications on MCM-41 changed water adsorption characteristics. Doped cations strengthened the water adsorption capacity at low RH following the order of Al–C12–Mg > Al–C12–Li > Al–C12–Na. Kinetics analysis indicated that capillary condensation process developed slowly due to low diffusion constant. But the adsorption transient uptake rates in capillary condensation sections were larger compared to other sections, Larger RH step not only resulted in larger uptake rate, but also promoted capillary condensation. Instead of calculating or measuring isotherms and diffusion coefficients respectively, parameters like transient uptake rate corresponding to the effects of both transport ability and adsorption capacity should be considered.