Water vapor adsorption of CaCl2-impregnated activated carbon

Kiyoshi Okada, Mari Nakanome, Yoshikazu Kameshima, Toshihiro Isobe, Akira Nakajima

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34 Citations (Scopus)


Activated carbons (AC) impregnated with the hygroscopic salt CaCl 2 were synthesized to enhance the amount of water vapor adsorbed at low relative pressure (P/P0). Possible applications for these materials are in adsorption heat pumps and desiccant air conditioners. The ACs were synthesized from tissue paper by chemical activation with K 2CO3 and the porous properties were investigated of a number of materials prepared under a variety of activation conditions. The highest specific surface area (SBET) (1820 m2/g) was obtained from the sample prepared with a K2CO3/sample ratio = 1/1 by mass, activated at 900 °C for 2 h under flowing N2 (2 L/min). Impregnation with CaCl2 was performed using 2.4-6.5 M CaCl2 solutions and a solution volume equal to the pore volume of the AC. XPS surface chemical analysis revealed that the impregnated CaCl 2 was mostly successfully impregnated into the pores while the surface CaCl2 increased gradually with increasing amount of impregnation. The adsorption of water vapor in the P/P0 range 0.1-0.3 (ΔW0.1-0.3) was dramatically increased by CaCl2 impregnation, the ΔW0.1-0.3 value reaching 0.52 g/g in the sample impregnated with 70 mass% CaCl2; this value is much higher than previously reported ΔW0.1-0.3 values.

Original languageEnglish
Pages (from-to)1549-1553
Number of pages5
JournalMaterials Research Bulletin
Issue number11
Publication statusPublished - Nov 2010


  • A. Amorphous materials
  • A. Microporous materials
  • D. Surface properties

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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