Micropore Size Analysis of Porous Carbons Using CO2 Adsorption at 273.15 K (0 °C)

Activated carbons in the form of fibers, pellets, granules, and powders are used in air filters, water purification systems, for removing organic impurities from various solutions, as well as in a variety of medical, environmental, and agricultural applications. These highly microporous, high surface area materials are often characterized by their apparent BET surface area and their pore size distribution (PSD). Measuring the PSD of microporous samples using nitrogen or argon adsorption is a slow process, requiring very low vacuum levels that require an expensive turbomolecular pump. Alternatively the PSD can be determined quickly using carbon dioxide at 0°C, at higher pressures than using nitrogen or argon, thus increasing throughput and reducing the equipment cost.