Preparation of highly mesoporous carbon membranes via a sol–gel process using resorcinol and formaldehyde

Preparation and characterization of carbon molecular sieve membranes based on resorcinol–formaldehyde resin

“…It has been reported that at this temperature gases from the amine decomposition generate micropores in the carbonized resorcinol-formaldehyde resin membrane [42]. Between 500 ºC and 800 ºC a lower weight loss of 15% is observed; at 900 ºC the total weight loss is approximately 44%; this weight loss is in accordance with the literature [35].…”

“…Dong et al [34] prepared microporous carbon membranes on α-alumina supports carbonizing resorcinol-formaldehyde polymer precursor and quaternary ammonium compounds (tetramethylammonium bromide and tetrapropylammonium) for dehydration of water/ethanol and water/isopropanol mixtures by pervaporation. Yoshimune et al [35] obtained highly mesoporous carbon membranes by carbonizing sol-gel derived mesoporous resorcinolformaldehyde membranes.…”

Designing Nanostructured Carbon Xerogels

“…However, other factors such as heating rate and carbonization atmosphere have also some influence on the textural properties of carbon gels (Kang et al, 2009). Overall, the heating rates used during pyrolysis are around 5-15 °C (Wu et al, 2004;Yoshimune et al, 2008;Zubizarreta et al, 2008a) since higher heating rates would mean a lower microporosity development, as reflected by several works that evaluate the different conditions in the carbonization processes of several carbon materials (Kuo et al, 2005;Liou, 2004). Regarding the influence of the carbonization atmosphere, it seems that inert gases produce the materials with the lowest textural development.…”

“…To prevent the formation of crystals which may deform the designed nanostructure of the polymer, the solvent is replaced before drying the gel. The most common solvent used for this purpose is t-butanol (Feaver & Cao, 2006;Mukai et al, 2005b;Yoshimune et al, 2008), as it causes fewer changes in density than water and the vapour pressure is higher, which reduced the drying time. The advantage of this type of drying process is the possibility of obtaining high mesopore volumes (Yoshimune et al, 2008).…”

“…The most common solvent used for this purpose is t-butanol (Feaver & Cao, 2006;Mukai et al, 2005b;Yoshimune et al, 2008), as it causes fewer changes in density than water and the vapour pressure is higher, which reduced the drying time. The advantage of this type of drying process is the possibility of obtaining high mesopore volumes (Yoshimune et al, 2008). As for the disadvantages, it should be highlighted that it is very difficult to prepare monoliths and in addition, in order to avoid the appearance of megalopores, it is necessary to perform a solvent exchange which entails an extra step and therefore and increase in time and costs.…”