The high performance bamboo charcoal for humidity control was prepared by carbonization with an agent of potassium compound. The mixture of potassium carbonate and raw bamboo chip with the mass ratio (K₂CO₃/Bamboo ratio) of 0.05, 0.1 and 0.5 was carbonized at 500 °C with heating rate of 25 °C /min under nitrogen flow for 2 hours using a tubular furnace. The surface area and the pore volume were measured with BET, α_s -plot and t-plot method, and surface functional groups were determined by Boehm titration. The results showed that the surface area was varied according to the K₂CO₃/Bamboo ratio. The surface area of bamboo charcoal with the low K₂CO₃/Bamboo ratio was smaller than that of original bamboo charcoal of 250 m²/g. However, the high K₂CO₃/Bamboo ratio resulted in the increase in the surface area of 472 m²/g, which was much larger than original bamboo charcoal. The amount of surface functional groups increased with the existence of K₂CO₃, and especially the carboxyl group greatly increased. The result of water vapor adsorption-desorption experiment for each prepared bamboo charcoal revealed that the charcoal with high amount of functional groups could uptake water vapor at low humidity region, while high amount of water vapor adsorption was observed for the charcoals possessing high pore volume content at medium-high humidity region. The water vapor adsorption- desorption experiment as a function of temperature was also performed assuming the seasonal temperature variation. The amount of water vapor adsorption-desorption did not depend on the sorts of bamboo charcoals. Accordingly, the bamboo charcoal carbonized with an agent of potassium compound could be expected as a superior humidity control material, which was hardly affecterd by seasonal temperature variation.

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