Production of nanoporous carbons from wood processing wastes and their use in supercapacitors and CO2 capture

Highly porous carbons were obtained from solid wastes generated in the chemical and the mechanical processing of birch wood (substandard kraft cellulose, hydrolysis lignin, chips and bark). NaOH-chemical activation of these residues at 575-800 degrees C resulted in an efficient process to produce carbons with specific surface areas well above 1000 m(2) g (1) and average pore widths of 1-1.7 nm. Comparative evaluations have shown the potentiality of wood wastes-based carbons in applications related to environmental protection. Activated carbons derived from chips- and bark-birch wood displayed specific capacitances as high as 308 F g (1) in the H2SO4 aqueous electrolyte and 200 F g (1) in the (C2H5)(4)NBF4/acetonitrile organic medium. Moreover, their capacitive performance at high current density competed well with that found for commercial carbons used in supercapacitors. Wood-derived carbons also proved to be highly promising for CO2 capture in power stations, achieving uptakes under post- and pre-combustion conditions of 11-16 wt.% and 49-91 wt.%, respectively. (C) 2012 Elsevier Ltd. All rights reserved.