Novel activated carbon for effective perfluoroalkyl substance (PFASs) removal by minimizing problematic desorption.

Research Project

Project/Area Number	20K22425
Research Category	Grant-in-Aid for Research Activity Start-up
Allocation Type	Multi-year Fund
Review Section	0303:Civil engineering, social systems engineering, safety engineering, disaster prevention engineering, and related fields
Research Institution	Hokkaido University
Principal Investigator	PAN LONG 北海道大学, 工学研究院, 博士研究員 (90884007)
Project Period (FY)	2020-09-11 – 2022-03-31
Project Status	Completed (Fiscal Year 2021)
Budget Amount *help	¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000) Fiscal Year 2021: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000) Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Keywords	微粉化活性炭 / 脱着 / 微量汚染物質 / 2-メチルイソボルネオール / 浸漬膜ハイブリッドシステム / 等価バックグラウンド化合物 / 2成分分岐型細孔拡散モデル / 細孔内に拡散性 / desorption / SPAC / branched-pore / 2-Methylisoborneol / coagulation / submerged-membrane / MF / diffusivity / pore diffusion model / adsorp-reversibility / micopollutant / PFAS / adsorption reversion / hydrophilizing milling / isotope visualization
Outline of Research at the Start	This research is to clarify the PFASs adsorption mechanisms, especially focusing on adsorption competition and adsorptive reversibility of PFASs on ACs. By understanding the mechanism, the most effective treatment system with novel micron-sized AC for removing target compounds will be achieved.
Outline of Final Research Achievements	This research studies the adsorption and desorption of target micro pollutants occurred on activated carbon (AC) in a submerged membrane hybrid system (SMHS). The micro pollutant was represented by 2-methylisoborneol (MIB) rather than perfluoroalkyl substance (PFAS) due to the analysis limitation under current experiment condition. The findings indicate that the AC in the SMHS should be replaced while the breakthrough concentration is low, not only to keep a high removal rate but also to decrease the desorption risk. The diffusivity of MIB molecules in the pores of the activated carbon particles decreased markedly in a short period of time. This decrease, which was attributed to fouling of the activated carbon in the SMHS by coagulant-treated water containing NOM, not only reduced the rate of MIB removal during the contamination period but also hindered the rate of MIB desorption during the no-contamination period and thus prevented the effluent MIB concentration from becoming high.
Academic Significance and Societal Importance of the Research Achievements	粉末活性炭への微量汚染物質の吸脱着特性の解析により、長期間使用された活性炭に存在する吸着汚染物質が著しく脱着する危険性を明らかにし、理論モデルとプログラムシミュレーションにより微量汚染物質の吸脱着の拡散移動特性を明らかにし、生産実用化のための注意事項を提案する。また、粉末活性炭と微粉化活性炭を同じ使用条件で微量汚染物質の吸着・脱着特性を比較し、凝集剤の使用の有無が実験結果に与える影響についても検討した。