Preparation and characterization of activated carbon fibers from liquefied wood by KOH activation
Abstract Activated carbon fibers (ACFs) have been prepared from liquefied wood (Wliq) by chemical activation with KOH, with a particular focus on the effect of KOH/fiber ratio in term of porous texture and surface chemistry. ACFs based on steam activation served as a blank for comparison. The properties of the ACFs were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), nitrogen adsorption/desorption, Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The results show that the KOH-activated ACFs have rougher surfaces and more amorphous structure compared with the blank. The pore development was significant when the KOH/fiber ratio reached 3, and achieved a maximum Brunauer-Emmett-Teller (BET) surface area of 1371 m2 g-1 and total pore volume (Vtot) of 0.777 cm3 g-1, of which 45.3% belong to mesopores with diameters of 2–4 nm, while the blank activated at the same temperature had a BET surface of 1250 m2 g-1 and Vtot of 0.644 cm3 g-1, which are mainly micropores. The surface functional groups are closely associated with the KOH/fiber ratios. KOH-activated ACFs with KOH/fiber ratio of 3 have more oxygenated surface functional groups (C-O, C=O, -COOH) than the blank.