(717b) Butanol Vapor Adsorption Behavior on Active Carbons and Zeolite Crystal

Butanol is considered to be a promising biofuel. However, the fermentation process for butanol production is restricted by its toxicity to the bacterial strains. Gas stripping technology can efficiently decrease butanol inhibition by removing it as it is produced. Adsorption can then be used to recover butanol from the vapor phase. Active carbon samples and zeolite were investigated for their butanol vapor adsorption capacities. Commercial activated carbon was hydrothermally modified with different H₂O₂ concentrations, and the specific surface area and oxygen-containing functional groups of activated carbon were tested before and after H₂O₂ modification. H₂O₂ hydrothermal modification increased the surface oxygen content, Brunauer-Emmett-Teller surface area, micropore volume, and total pore volume of active carbon. The adsorption capacities of these active carbon samples were almost three times that of zeolite. However, the un-modified active carbon had the highest adsorption capacity for butanol vapor (259.6 mg g^-1), compared to 222.4 mg g^-1 after H₂O₂ hydrothermal treatment. Both modified and un-modified active carbon can be easily regenerated for repeatable adsorption by heating to 150 °C. Therefore, surface oxygen groups significantly reduced the adsorption capacity of active carbons for butanol vapor. This impact of surface oxygen functional group also enable engineers and scientists understand as well as predict loss of dynamic organic vapor adsorption capacity of carbon adsorbents during high temperature steam or air regeneration.