Adsorption–desorption of water vapour on chars prepared from commercial wood charcoals, in relation to their chemical composition, surface chemistry and pore structure

Equilibrium and dynamic vapour water sorption properties of biochar derived from apple wood

“…The amount of sorbed water attributed to the slow sorption process is much less for the charred samples compared to the unmodified wood sample. Such differences in the water vapour sorption behaviour between chars and activated chars have been commented on before [30].…”

Lignin and derivative charcoals: Functional groups involved in the adsorption phenomenon

“…The (C=C) stretching vibrations related to the aliphatic functional groups, which appear as shoulder around 1640 cm -1 on the IR spectrum of raw lignin, persist in the same form in the case of CL400 and disappear in the case of CL600 and CL800 [10,43]. However, the skeletal vibrations (C=C) in the aromatic rings that existed in the lignin persist in the three coals [10,13,42,43] with a slight shift to either low or high frequencies (table 1). In this regard, no explanation is advanced in the literature [7,17].…”

“…The loss of these groups occurs during the carbonization of all biomasses [7, 9-11, 13, 14, 16, 17, 21, 42, 43]. This loss indicates that these functional groups are thermally unstable [10,11,42]. Moreover, the bands corresponding to the stretching vibrations of methyl and methylene groups are no longer discernable in the coals.…”

“…Moreover, the bands corresponding to the stretching vibrations of methyl and methylene groups are no longer discernable in the coals. The loss of these groups is in favor of a reduction in aliphaticity [7-10, 13, 17, 43] and an increase in aromaticity [7,9,10,17,42,43]. The development of the latter is supported by the increase of intensity of the aromatic vibrations of (C-H) out-of-plane deformation and by the appearance of new absorptions at 851 and 750 cm -1 attached to these vibrations ( Regarding (C=O) vibration at 1740 cm -1 related to the carbonyl groups, it takes the form of shoulder on the infrared spectra of CL400 and CL600 as in the case of raw lignin (table 1).…”

Measuring the bioavailability of polychlorinated biphenyls to earthworms in soil enriched with biochar or activated carbon using triolein-embedded cellulose acetate membrane

“…The high H:C ratio for the WC biochar suggested that it contained large amounts of original organic residues, such as polymeric CH 2 , fatty acids, lignin (aromatic core), and some cellulose (polar fractions). The overall low molar O:C ratio in the two biochar types indicates that their surfaces became less hydrophilic (Chen et al 2008;Pastor-Villegas et al 2010). Table 2 for the respective BAFs for all treatment combinations).…”