Computer analysis of the microporous structure of activated carbon fibres using the fast multivariant identification procedure of adsorption system parameters

Activated carbons from common nettle as potential adsorbents for CO2 capture

Activated carbons (ACs) prepared from common nettle (Urtica Dioica L.) were studied in terms of carbon dioxide adsorption. ACs were prepared by KOH chemical activation in a nitrogen atmosphere at temperatures (ranging from 500 to 850°C). The pore structure and the surface characterization of the ACs were specified based on adsorption-desorption isotherms of nitrogen measured at –196°C and carbon dioxide at 0°C. The specific surface area was calculated according to the BET equation. The pore volume was estimated using the DFT method. The highest values of the specific surface area (SSA) showed activated carbons produced at higher carbonization temperatures. All samples revealed presence of micropores and mesopores with a diameter range of 0.3–10 nm. The highest value of the CO2 adsorption, 4.22 mmol/g, was found for the material activated at 700°C.

SEM and AFM Studies on the Surface and Cross Section Morphology of Rayon-Based Activated Carbon Fibers

The surface and cross section morphology of rayon-based carbon fibers (RCF) and the resulting rayon-based activated carbon fibers (RACF) were investigated through scanning electron microscopy and atomic force microscopy. It was found that the surface of RCF exhibited grooves and striations with the width ranging from 30 to 90 nm, and the striation distribution was about 25 bars per µm around the circumference. While on the RACF, lots of pores emerged on the surface and superficial cross section (about 1 ~ 2 µm to the surface), namely, the external section was porosity but the interior section was close-grained. It was detected that the pore sizes ranged from 50 to 550 nm and the approximate pore distribution was 10 pores in 1×1 µm2. Furthermore, the walls of pores were not smooth but consisted of continuous grains with the diameters about 30 nm.