A new determination method of absolute adsorption isotherm of supercritical gases under high pressure with a special relevance to density-funcitional theory study

摘要

A new determination method of an absolute adsorbedamount n_(ab from the surface excess mass n_(ex) for high-pressure adsorption isotherms of a suercritica gas was proposed.The effectiveness of new method was examined by using the density-functional theory (DFT).The DFT study showe dthat thsi analysis can provide reasonable results;both of the absolute adsorbed amount determined from the proposed method and the DFT agreed within 5% at 90 MPa and only 1% below 5 MPa. Furthermore,we applied this new method to the experimental surface excess isotherm in the literature,which has a maximum.The analyzed absorlute adsorption isotherm from the surface excess adsorption isotherm having a maximum were of IUPAC type I or type II.This method gave the thickness of the interfacial layer of the adsorbed phase.