Desorption of butanol, water and ABE mixture from activated
carbon was first studied by thermogravimetry. Briefly, butanol,
water and ABE mixture with a ratio of 6:3:1 were first adsorbedonto activated carbon for 24 h to reach saturation. Then, free (unadsorbed)
water and solvents were removed from the ‘wet’ activated
carbon by patting with filter paper. Butanol desorption from
the ‘‘loaded” activated carbon (initial weight: 30.37 ± 0.18 g) was
then carried out by heating at a gradually increased temperature
(10 C/min), from 25 C to 250 C, until reaching a constant weight.
A two-step heating process for butanol desorption was then studied.
Briefly, 10 g of activated carbon was equilibrated in 300 ml
model solution (15 g/L butanol) at 37 C with agitation at
25 rpm for 24 h. After removing free water and un-adsorbed butanol
with filter paper and aspiration through a 50 ml syringe, the
partially dried adsorbents were heated first at 40 C to remove
water, and then heated at 200 C for butanol recovery.
2.5.