Abstract—Concrete sludge is an industrial waste slurry containing hydrated cement, aggregates, and water. In the current study, anion-exchange materials: ettringite, metaettringite, and Ca-Al layered double hydroxide were synthesized from concrete sludge, and tested to see if they could remove harmful anions (borate, fluoride, and chromate) from solutions. Metaettringite showed high borate and fluoride removal ability, reducing initial concentrations of 100 mg B/L and 300 mg F/L to 6.3 mg B/L and 14.5 mg F/L. The Ca-Al layered double hydroxide showed high fluoride and chromate removal ability, reducing initial concentrations of 300 mg F/L and 180 mg Cr/L to 14.5 mg F/L and 0.4 mg Cr/L.
Index Terms—Anion exchange material, concrete sludge, harmful anions, ettringite, layered double hydroxide, removal.
T. Hongo is with the Faculty of Science and Engineering, Waseda University, Tokyo, Japan (e-mail: peea.hongo@hotmail.co.jp).
Y. Tsunashima and A. Yamasaki are with the Faculty of Science and Technology, Tokyo, Japan.
A. Iizuka is with Institute of Multidisciplinary Research for Advance Materials, Tohoku University, Miyagi, Japan.
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Cite: T. Hongo, Y. Tsunashima, A. Iizuka, and A. Yamasaki, "Synthesis of Anion-Exchange Materials from Concrete Sludge and Evaluation of Their Ability to Remove Harmful Anions (Borate, Fluoride, and Chromate)," International Journal of Chemical Engineering and Applications vol. 5, no. 4 pp. 298-302, 2014.
