Wood-based materials are also attracting attention because they are good absorbers of volatile organic compounds (VOCs). Woodceramics are carbon/carbon composite materials consisting of plant-originated amorphous carbon reinforced by glassy carbon generated from phenol resin. Woodceramics had been produced by impregnating wood-based (lignocellulosic) materials, such as hiba, cedar, pine, MDF (medium density fiber) boards, waste paper, apple wastes, etc., with phenol resin, and by then calcining the resulting material. Thus, they are porous materials having a BET specific surface area of about 500 m2g-1, and have potential as adsorbents. From this point of view, adsorption properties of wood and woodceramics were evaluated by using the rapid measuring method for VOCs developed by Nishimoto et al. This method had been developed by using thermogravimetry (TG) and gas chromatography (GC), based on the findings that the sum of the peak areas obtained in a predetermined duration of time in the chromatogram is directly related to the amount of gas species evolved from the sample. Thus, a small amount (50mg) of the sample was sealed in a vial with the adsorbates, and were kept at a certain temperature (383 K) for 1 hour. Then, 1 ml of the gas phase was taken and measured by GC (HP6890, equipped with HP6890 FID and DB-1 capillary column) using He as the carrier gas. In this manner, adsorption power of woodceramics for carvone, pulegone, geraniol, citronellol, menthone, nerol, and citral was evaluated. Woodceramics showed different preferences on the adsorption on gases and perfumery materials. For instance, cedar-based woodceramics showed strong adsorption power particularly on geraniol and citral, in which more than 99.9% of the compounds were adsorbed. About 99.7-99.8% of pulegone and menthone, 99.0% of nerol, 97.9% of carvone, and 94.0% of citronellol were adsorbed by the cedar-based woodceramics. The adsorption properties of other woodceramics are also reported and compared. Thermal analyses are also reported.
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