Synthesizing activated carbons from resi

We prepared activated carbons from phenol–formaldehyde (PF) and urea–formaldehyde (UF) resins by chemical activation with K2CO3, involving impregnation during the synthesis of the resins. The influence of carbonization temperature ranging from 773 to 1173 K on the pore structure, specifically the specific surface area and pore volume, was investigated. Results indicated that the specific surface area and micropore volume of PF-derived activated carbon (PF–AC) and UF-derived activated carbon (UF–AC) increased with the carbonization temperature within the specified range. Activated carbon with well-developed micropores was achieved from PF, and activated carbon with a high specific surface area exceeding 3000 m²/g and substantial meso-pore volume was obtained from UF. We deduced the activation mechanism through thermogravimetry and X-ray diffraction analyses. For the production of activated carbon from PF, K2CO3 was reduced by carbon in the PF char, leading to the release of CO gas and resulting in an increase in the specific surface area and pore volume above 1000 K. In contrast, for UF, above 900 K, the carbon within the UF char was consumed during the K2CO3 reduction step.