Effects of probing vapors and temperature on the characterization of micro-mesopore size distribution of carbonaceous materials

A technique for determining micro-mesopore size distribution developed by Nguyen and Do [Nguyen, C.; Do, D. D. Langmuir 1999, 15, 3608] is tested with nitrogen adsorption data at 77 K and benzene adsorption data at near ambient temperatures of two carbonaceous samples. The PSD results using nitrogen data are compared with the results obtained from the DFT technique. In general, they agree very well with each other, though sharper micro and mesopore peaks are observed with our results. The PSDs derived from benzene adsorption data using our technique are practically independent of temperature, reinforcing the assertion that the PSD is the porous media's intrinsic property. However when this benzene-derived PSD is compared with nitrogen-derived PSD, some small but subtle differences are observed. This could be due to the difference in the gas-solid interaction, the molecule packing in pores, and the adsorption temperatures of nitrogen (77 K) and benzene (near ambient).