A computational model of an Einstein-Solid model to study gas sorption in solid surfaces: effects on the solid wall structure

Abstract

Sorption of carbon dioxide (CO$_2$) on solid surfaces is studied by a Reactive Monte Carlo (RxMC) method. A simple model of the\linebreak A+B $\rightleftharpoons$ C reaction is used to mimic the experimental reactions CO$_2$ + Li$_2$O $\rightleftharpoons$ Li$_2$CO$_3$. Two different solid surfaces were constructed to study sorption of the gas, a face centered cubic (FCC) and a disordered walls. In each case the solids were composed of particles with two different models, the first one consisted of rigid particles and the second model considered particles which were allowed to vibrate inside the solid with a given spring constant, i.e. a solid of Einstein. Density profiles analysis showed that not only physisorption but also chemisorption was observed. Comparisons of gas absorption of the two walls with a cubic simple solid structure, reported previously, were carried out and it was observed that the disordered and the cubic simple walls present similar values. However, the FCC walls produced higher absorption than the others, in particular at low temperatures.