National Institute of Advanced Industrial Science and Technology

Chieko Ikeda

Masaki Maeda

Masaya Suzuki

Keiichi Inukai

Koji Tajiri

Katsuhiro Tsukimura

Sumiko Kawabata

Ryousuke Nakanishi

Provided is an adsorbent having superior adsorption properties for use as a dehumidifying agent for desiccant air conditioning which exhibits high adsorption properties at mid and high humidity ranges, and for use as a gas adsorbent of carbon dioxide, ammonia, formaldehyde and the like. A precursor suspension having a Si/Al ratio of 0.70 to 1.0 is prepared, and the precursor suspension is subsequently heated at 110&#xb0; C. or higher for 2 days to synthesize a complex of a layered low-crystalline clay mineral and an amorphous aluminum silicate. The obtained complex of the layered low-crystalline clay mineral and the amorphous aluminum silicate yields excellent water vapor adsorption performance of 45 wt % or more at a relative humidity of 60%, and therefore can be used as an adsorbent for desiccant air conditioning. The complex also yields excellent carbon dioxide absorption/desorption performance of 12 wt % or more at 100 kPa to 900 kPa, and therefore can be used as a gas adsorbent for gas such as ammonia and formaldehyde.

Aluminum silicate complex and high-performance adsorbent comprising the same

Provided is an adsorbent adapted to adsorb carbon dioxide by increasing the pressure, and to carry out 10% or more adsorption and adsorption of the adsorbed carbon dioxide by lowering the pressure at atmospheric pressure or higher in a range of 100 to 900 kPa without vacuuming or the like. As a result of using amorphous aluminum silicate with a Si/Al ratio of 0.7 to 1.0 and having a peak in the vicinity of &#x2212;78 ppm and &#x2212;87 ppm in aSi solid NMR spectrum, adsorption and desorption of 10 wt % or more can be performed in a range of 100 to 900 kPa, and this can be used as a carbon dioxide adsorbent mainly in the pressure swing adsorption method.

Carbon dioxide adsorbent capable of adsorption and desorption in dependence on pressure of atmospheric pressure or higher

Provided is an adsorbent having excellent adsorption performance in a medium-humidity range by employing an amorphous aluminum silicate formed from protoimogolite. The amorphous aluminum silicate formed from protoimogolite is synthesized by setting the Si/Al ratio in solution mixing to be of a condition that is higher than synthesizing imogolite or amorphous imogolite, and performing desalting treatment and heating thereto. The obtained amorphous aluminum silicate formed from protoimogolite yields a superior water vapor adsorption performance of 30 wt % or higher at a relative humidity of 60%, and can be used as an adsorbent for desiccant air conditioning.

Amorphous aluminum silicate and adsorbent each having excellent moisture adsorption/desorption characteristics in medium-humidity range

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Ibaraki, Japan

Chieko Ikeda