Using thermodynamic models to present adsorption of Nanostructures at high pressure

Adsorption models are used to simulation and design of adsorption processes. Due to the variety of nanostructure usage in these processes, development of the gas adsorption models is necessary. In this study, van der Waals and Peng - Robinson equations have been modified to describe the behavior of fluids in a Nano pore. Two models have been offered by using the modified equations and their standard equations to predict high pressure adsorption of pure gases. The results show that the model based on modified van der Waals equation do not have acceptable results at lower pressure than 5MPa but results at higher pressure than 5MP are better and average deviation from experimental data at this range is 3.31%, when as the precision of the second model in the most cases are acceptable at pressure range 1MPa to 12MPa and average deviation is 6.41%. Checking the effect of adsorbent pore diameter shows the amount of adsorption decreases with increasing pore diameter. In addition, the vapor pressure of carbon dioxide in Nano pore has been studied. The results display that in constant temperature the vapor pressure of the fluid in bulk state is more than the Nano pore and the vapor pressure also decreases with decreasing pore diameter. At the end, the results show that the critical temperature of the fluid in Nano pore decreases with decreasing pore diameter.