Isotope Microscopy Visualization of Adsorption Profile Verifies the Mechanism of Higher Adsorption Capacity on Super-fine Powdered Activated Carbon

• Project/Area Number: 25550049
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Environmental engineering and reduction of environmental burden
• Research Institution: Hokkaido University
• Principal Investigator: MATSUI Yoshihiko 北海道大学, 工学(系)研究科(研究院), 教授 (00173790)
• Co-Investigator(Kenkyū-buntansha): MATSUSHITA Taku 北海道大学, 大学院工学研究院, 准教授 (30283401)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Project Status: Completed (Fiscal Year 2014)
• Budget Amount: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000); Fiscal Year 2014: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000); Fiscal Year 2013: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
• Keywords: 用排水システム / 環境技術 / 環境材料 / 土木環境システム / 反応・分離工学 / 水資源

Outline of Final Research Achievements

Decreasing the particle size of powdered activated carbon may enhance its equilibrium adsorption capacity for some compounds, such as geosmin, 2-methylisoborneol, and polystyrene sulfonates. Shell adsorption model (SAM), in which adsorbates preferentially adsorb near the exterior surface of the adsorbent particle, may explain this enhancement. This study used isotope microscopy and deuterium-labeled adsorbates to directly visualize the solid-phase concentration profiles of these compounds in carbon particles. The deuterium/hydrogen ratio, which was used as an index of the solid-phase concentration of the adsorbates, was higher in the shell region than in the inner region of carbon particles. Solid-phase concentrations obtained from the deuterium/hydrogen ratio roughly agreed with those predicted by SAM analyses of isotherm data. The direct visualization of the localization of compounds in carbon particles explained the mechanism of the equilibrium adsorption capacity enhancement.

Research Products

• [Journal Article] Isotope microscopy visualization of the adsorption profile of 2-methylisoborneol and geosmin in powdered activated carbon (2014)
  • Author(s): Matsui, Y., Sakamoto, A., Nakao, S., Taniguchi, T., Matsushita, T., Shirasaki, N., Sakamoto, N. and Yurimoto, H.
  • Journal Title: Environmental Science & Technology Volume: 48 Issue: 18 Pages: 10897-10903
  • DOI: 10.1021/es5024515
  • Peer Reviewed
• [Presentation] 2-メチルイソボルネオールとジェオスミンは活性炭のどこに吸着するのか：同位体顕微鏡を用いた直接観察 (2015)
  • Author(s): 坂本明日香, 松井佳彦, 中尾聡一, 谷口琢磨, 松下拓, 白崎伸隆
  • Organizer: 第49回日本水環境学会年会
  • Place of Presentation: 金沢
  • Year and Date: 2015-03-16 – 2015-03-18
• [Presentation] Where in an activated carbon particle MIB and geosmin adsorb: isotope micro-mapping (2014)
  • Author(s): Sakamoto, A., *Matsui, Y., Nakao, S., Taniguchi, T., Shirasaki, N. and Matsushita, T.
  • Organizer: International Water Association World Water Congress
  • Place of Presentation: Lisbon, Portugal
  • Year and Date: 2014-09-21 – 2014-09-26
• [Presentation] Enhanced removal of 2-MIB and geosmin by super-fine PAC: Evidence of shell adsorption. (2013)
  • Author(s): 1.Matsui, Y., Nakao, S., Taniguchi, T., Sakamoto, A., Shirasaki, N. and Matsushita, T.
  • Organizer: The Tenth IWA Symposium on Off-Flavours in the Aquatic Environment
  • Place of Presentation: National Cheng Kung University, Tainan, Taiwan