The shielding potential concept for evaluation of surface chemistry and topology from sorption isotherms: Water interaction with alumino-silicate minerals

Physical adsorption isotherms of gases and vapors are well described as a simple exponential function of the Polanyi sorption potential and provide an inherently valuable means of evaluation of monolayer capacity for solid sorbents…. Additional features are noted that allow evaluations of porosity and other topological features. The energetics of water vapor sorption can involve chemical and structural processes depending on the given substrate. This project reexamines water sorption isotherms on aluminum silicate minerals from: (1) geothermal formations of interest in commercial energy production and (2) hardened Portland cements. The results are informative and again emphasize the benefits of direct analyses of the isotherms without the need for comparison to reference isotherms (t-plots, n-plots, αs, etc.) as representative of a nonporous substrate of comparable chemical and structural composition.