TY - JOUR
T1 - Elution characteristics of undesirable anionic species from fly ash blended cement in different aqueous solutions
AU - Sasaki, Keiko
AU - Nakama, Shingo
AU - Tian, Quanzhi
AU - Guo, Binglin
AU - Wang, Mengmeng
AU - Takagi, Ryoichi
AU - Takahashi, Tomohiko
N1 - Funding Information:
Financial support was provided to KS by Japan Society for the Promotion of Science (Ja JSPS ) KAKENHI research grants ( JP19H00883 ). TEM-EDX observations were conducted at the High Voltage Electron Microscopy Center in Kyushu University. ICP-MS measurement was performed at Advanced Analytical Center in Kyushu University.
Publisher Copyright:
© 2021 Elsevier Ltd.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/6
Y1 - 2021/6
N2 - There are few reports to explore immobilization of undesirable anionic species released from fly ash (FA) blended cement. This study clarifies the stabilities of several undesirable anionic species, through dissolution tests under a different matrix. The immobilization mechanism mainly involves co-precipitation with ettringite and hydrocalumite, the marginal formation of insoluble Ca salts, and occlusion in calcium silicate hydrates and amorphous phases produced during the pozzolanic reaction. The products released some amounts of chromate, arsenate, and selenite but not borate in dissolution tests. Elution of borate was the most effectively immobilized by Ca additives, owing to selective incorporation in ettringite. Moreover, selenite showed a trend of dissolving in acidic conditions, presumably owing to the dissolution of CaSeO3 with relatively high Ksp in addition to coprecipitation with hydrocalumite and ettringite. Under the present mixing condition of cementation, only selenite is a cautionary species which excessively eluted over the environmental standard.
AB - There are few reports to explore immobilization of undesirable anionic species released from fly ash (FA) blended cement. This study clarifies the stabilities of several undesirable anionic species, through dissolution tests under a different matrix. The immobilization mechanism mainly involves co-precipitation with ettringite and hydrocalumite, the marginal formation of insoluble Ca salts, and occlusion in calcium silicate hydrates and amorphous phases produced during the pozzolanic reaction. The products released some amounts of chromate, arsenate, and selenite but not borate in dissolution tests. Elution of borate was the most effectively immobilized by Ca additives, owing to selective incorporation in ettringite. Moreover, selenite showed a trend of dissolving in acidic conditions, presumably owing to the dissolution of CaSeO3 with relatively high Ksp in addition to coprecipitation with hydrocalumite and ettringite. Under the present mixing condition of cementation, only selenite is a cautionary species which excessively eluted over the environmental standard.
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U2 - 10.1016/j.jece.2021.105171
DO - 10.1016/j.jece.2021.105171
M3 - Article
AN - SCOPUS:85101455095
SN - 2213-3437
VL - 9
JO - Journal of Environmental Chemical Engineering
JF - Journal of Environmental Chemical Engineering
IS - 3
M1 - 105171
ER -