Adsorption of hydrogen on porous materials of activated carbon and zeolite NaX crossover critical temperature

被引：19

作者：

Li, Jing ^{[1
]}

Wu, Erdong ^{[1
]}

机构：

[1] Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China

来源：

JOURNAL OF SUPERCRITICAL FLUIDS | 2009年 / 49卷 / 02期

关键词：

Hydrogen adsorption isotherm; Activated carbon; Zeolite Nax; Critical temperature; Compressibility factor; HIGH-PRESSURE ADSORPTION; SUPERCRITICAL HYDROGEN; PHYSISORPTION; ISOTHERMS; CONDENSATION; CAPACITY; BEHAVIOR; DIOXIDE; METHANE; FLUIDS;

D O I：

10.1016/j.supflu.2008.12.015

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Hydrogen adsorption properties of typical porous materials, activated carbon and zeolite NaX, are studied through isotherm measurements at pressure up to 7 MPa crossover the critical temperature. The Soave-Redlich-Kwong equation of state is selected for calculation of compressibility factor of hydrogen. The two adsorbents exhibit remarkably different hydrogen uptake capacities. which are attributed to their framework structures and porous surfaces. At near critical temperatures, significant drops and recoveries of excess adsorption are observed on the isotherms. The multilayer adsorption and associated reduced density and increased volume of the adsorbed phase are derived from the extents of adsorption drops. The recovery is attributed to the bias of compressibility factor from the assumed equation of state. The negative adsorption is observed at subcritical temperature, and explained by the conception of pore critical temperature and relevant calculation. The isosteric heats of adsorption are determined as 2.1 kJ/mol for activated carbon and 4.4 kJ/mol for NaX, respectively.

引用

页码：196 / 202

页数：7

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