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Gas-templated resorcinol formaldehyde-activated carbon xerogels (GT-RF-ACXs) were prepared from resorcinol-formaldehyde xerogels that were templated by infusing different gases (e.g., nitrogen, oxygen, methane, ethylene, ethane, propylene, n-butane, air, propane, helium, argon, carbon dioxide and hydrogen) into the sol media upon its gelation, with subsequent carbonization and activation of the gas-templated xerogels. The crystallinity, adsorption isotherms; pore structure, chemical structure and particle size of GT-RF-ACXs were studied. Wide ranges of characteristics were obtained for GT-RF-ACXs templated with different gases. The effect of templating with different gases on the adsorption performances of GT-RF-ACXs were demonstrated in aqueous media for the removal of (Ni2+, Pb2+ or Cr3+) ions from water; and in gas media for the adsorption of CO 2 , CH 4 and N 2. It was found that the gas-templating has a strong effect on the adsorption performance of GT-RF-ACXs towards different species in aqueous or gas media. Therefore, it is evident that gas-infusion during the synthesis of gel precursors significantly affects the features and their separation abilities of their subsequent activated carbons. • Gas-templated carbon xerogels were fabricated. • Effect of infused gas on carbon xerogels properties. • Effect of infused gas on pore structures. • Effect of infused gas on adsorption of gas and metal ions. [ABSTRACT FROM AUTHOR]

Effects of micro- and mesoporosity of resorcinol-formaldehyde xerogels (RFXs) on the adsorptive properties of crystal violet (CV) were investigated. RFXs were synthesized at different pH values, and corresponding pore structures were examined. RFXs were characterized by thermal gravimetric analysis, scanning electron microscopy, and wide-angle X-ray diffraction. RFXs performed efficiently for removing CV from water, and were easily regenerated. RFXs synthesized at pHs of 5.5 and 7.0 exhibited relatively high surface areas and micropore volumes, whereas those synthesized at pH 2.5 exhibited relatively low surface areas and micropore volumes. Overall, surface areas of RFXs increased when increasing the pH of RF solutions, and this corresponded to higher CV adsorption capacities. This work is the first of its kind for studying the use of RFXs in the removal of such dyes from wastewater, and is anticipated to have a major impact on the treatment of wastewater generated by textiles industries. [ABSTRACT FROM AUTHOR]

Hybrid chitosan-resorcinol/formaldehyde xerogels were synthesized, and the effect of including minor quantities of chitosan on the consequent activated carbon was investigated. The resulting activated carbon were characterized by different techniques. Clear changes were found in the structure of activated carbon as a result of including chitosan in the synthesis. The results showed that the disorder ratio of crystal lattice decreased from 0.750 to 0.628 when increasing the concentration of chitosan from 0 to 0.037 wt%. The micropores increased from ~0.3% to ~1.0%, mesopores increased from ~11.2% to ~32.9% and macropores decreased from ~88.4% to ~66.1%. The total pore volume decreased from 1.040 to 0.238 cm3/g and the total pore surface area decreased from 912.3 to 554.4 m2/g. On the other hand, the average pore width decreased from 2.3 to 0.8 nm and the average particle size decreased from 224 to 149 nm. Nano-scale Scanning Electron Microscope (NanoSEM) morphology indicated a critical composition of chitosan (0.022 wt%) that affects the structure and thermal stability of activated carbon produced. [ABSTRACT FROM AUTHOR]