Synthesis and characterization of porous carbons by the sol-gel method from resorcinol-formaldehyde resin

ABSTRACT

Nine carbon xerogels were synthesized from resorcinol formaldehyde resin [RF], under increasing resorcinol/catalyst, Na2CO3, [R/C] molar ratios [50, 500. 1000], followed by pyrolysis at temperatures of 500, 600 and 700°C, under no external flow of gases. One organic xerogel was included for the sake of comparison. Drying of the RF hydrogels was carried out by the conventional evaporation technique in static air to get the RF xerogel Obtained carbons were characterized by CHO content, TEM, and N2/77K adsorption. Porosity characteristics were calculated by applying the well established alpha s plots to get various textural parameters. It was found that an increase in surface area, and pore volume was associated with corresponding rise in the R/C molar ratios. Most porosity, mainly, existed within the micropore size range, particularly for xerogels developed at 600 or 700°C, Thus. well-developed porous activated carbons could be obtained from an organic RF-xerogel by pyrolysis at 700°C and at high R/C-precursor ratios [500 and 1000]. The described simple conditions of preparation might encourage the pilot-scale production of porous carbon xerogels, suitable as adsorbents in liquid-phase environmental treatment processes