Synthesizing activated carbons from resins by chemical activation with K 2CO 3

Abstract

We prepared activated carbons from phenol–formaldehyde (PF) and urea–formaldehyde (UF) resins by chemical activation with K 2CO 3 with impregnation during the synthesis of the resins. The influence of carbonization temperature (773–1173 K) on the pore structure (specific surface area and pore volume) and the temperature range at which K 2CO 3 worked effectively as an activation reagent, were investigated. The specific surface area and micropore volume of PF–AC and UF–AC increased with an increase of carbonization temperature in the range of 773–1173 K. We prepared activated carbon with well-developed micropores from PF, and activated carbon with high specific surface area (>3000 m 2/g) and large meso-pore volume from UF. We deduced the activation mechanism with thermogravimetry and X-ray diffraction. In preparing activated carbon from PF, K 2CO 3 was reduced by carbon in the PF char. The carbon was removed as CO gas resulting in increased specific surface area and pore volume above 1000 K. In preparing AC from UF, above 900 K the carbon in UF char was consumed during the K 2CO 3 reduction step.