Artefact peaks of pore size distributions caused by unclosed sorption isotherm and tensile strength effect

The pore size distribution (PSD) is an important property of the porous materials, but an accurate and reliable PSD is very difficult to obtain. Quenched Solid Density Functional Theory (QSDFT) is widely used to analyze the pore size distribution. Here, a series of unclosed and closed isotherms of activated carbon were measured and compared. The experimental results revealed the appearance of an artefact peak in the PSD for the unclosed isotherms by employing QSDFT equilibrium model. Moreover, the location of the artificial peak is highly related to the end point of the desorption branch. In addition, tensile strength effect (TSE) illustrates the limit of mechanical stability of liquids in pores, and subsequent cavitation generates an artefact peak at around 2.8 nm. Interestingly, it was found that isotherm data associated with TSE can be used to calculate the total pore volume of all large cavities in which cavitation occurs.