Isosteric heat and selectivity in adsorption of gases in rough pores: In Henry’s law region

Abstract

Henry constant and isosteric heat of adsorption are important parameters for characterizing the gas-solid interaction in an adsorption process. In order to better understand the adsorption behavior of gas in rough pores, we construct rough slit pores by using two rectangular corrugated substrates, and then calculate the potential profile in it. By utilizing classical statistical mechanics, the longitudinal Henry constant and isosteric heat of <inline-formula><tex-math id="M3">\begin{document}$ \text{H}_{2} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20212348_M3.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20212348_M3.png"/></alternatives></inline-formula> are further calculated in the Henry region. The results suggest that both geometric morphology and pore width can significantly influence and modulate the longitudinal Henry constant and isosteric heat of the gas in the pore. Furthermore, the selectivity of adsorption in the binary <inline-formula><tex-math id="M4">\begin{document}$ \text{CO}_{2}/ \text{H}_{2} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20212348_M4.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20212348_M4.png"/></alternatives></inline-formula> mixture is also calculated and investigated in the Henry region. In addition, the effects of corrugated substrates with different geometries on adsorption properties are also calculated and studied. The result can provide reliable theoretical basis for understanding the adsorption, separation and purification of the gas in porous materials, and it is also expected to provide helpful idea for designing and exploring new nano functional materials.