Letter to the editor

Excerpt

The authors of the paper claim to present a review article on measurement of surface resistance (known as surface barrier as well) to molecular transport in microporous sorbent particles as observed by sorption kinetic methods. They refer to sorption rate data collected by several experimental techniques: direct uptake rate measurements, zero length column (ZLC), frequency response, PFG NMR and interference microscopy. As to direct uptake measurements, two sorption kinetics methods that are usually executed at either constant pressure or constant volume-variable pressure conditions are mentioned in the article. Beside formulas for evaluation of experimental data to obtain effective diffusion coefficients, some results being of older date, are offered to the reader. …