Preparation of porous carbons from phenol-formaldehyde , urea-formaldehyde resins and the application
We prepared activated carbons from phenol-formaldehyde(PF) and urea-formaldehyde(UF) resins. The influence of carbonization temperature (773-1173K) on the pore properties (specific surface area and pore volume and pore size) of the activated carbons was investigated. The specific surface area and micropore volume of PF-ACs and UF-ACs increased with increasing carbonization temperature in the range of 773-1173 K. We prepared activated carbons with well developed micropores from PF, and activated carbons with high specific surface area and large meso-pore volume from UF. We prepared molecular sieving carbons (MSCs) from phenol-urea-formaldehyde (PUF) resins which were synthesized with different Urea/Phenol (U/P) ration. The effects of the blend ration (U/P = 0.5-3.0) on the pore properties (pore volume and pore size) of the MSCs were investigated. The U/P ration had a significant effect on the pyrolysing behavior; at a specified value of the U/P ration, the pore size of the prepared MSC could be controlled in an extremely narrow range. It was found that the MSCs with the controlled pore size range in 0.35-0.41 nm exhibited excellent adsorption selectivity for separating CO2 and CH4 and those with the controlled pore size range in 0.40-0.43 nm did the same thing for separating C3H8 and C3H6.