【Paper】
Abilities of Intensified Humidity-control-charcoal Produced from Wood Waste
Akio Nakanishi*, Motoharu Tamai*, Seiki Tanada**, Takeo Nakamura** and Naohito Kawasaki**
* School of Science and Engineering, Kinki University
** School of Pharmaceutical Science, Kinki University
† Correspondence should be addressed to Akio Nakanishi:
Environmental Material Lab., School of Science and Engineering, Kinki University
（3-4-1 Kowakae, Higashi-osaka, Osaka, 577-8502 Japan）

Abstract
Intensified humidity-control-charcoals（IHCCs）are produced from wood waste. IHCCs are intensified by two kinds of salt, sodium chloride and calcium chloride. Conventional charcoals have no high humidity control capacity; the absorption of steam into charcoals is particularly limited in the high humidity range（over 60％RH）. IHCCs are free from that limitation.
Absorption of steam into IHCCs occurs in two phases, an adsorption phase and a reserve phase. The absorption phase is the process by which the salts attract steam from the atmosphere. The reserve phase is the process by which the charcoal retains that steam as water. Analyzing and improving IHCCs using this division of processes, the humidity control ability of IHCCs was increased to 1.2−4.0 times that of conventional charcoals. Moreover, IHCCs using calcium chloride have a higher humidity control ability than those using sodium chloride.
Humidity-control materials require durability for their practical application. Silica gel has a higher humidity control ability than charcoals and IHCCs, but the durability of its absorption ability of steam is lower than that of other materials. Considering these characteristics together, IHCCs offer higher humidity control ability than regular charcoal and a higher durability of steam absorption than silica gel.

Key words: wood waste, recycling system, charcoal, intensified humidity-control-charcoal, division of steam absorption process