TY - JOUR
T1 - Effects of Mg compounds in hydroxylated calcined dolomite as an effective and sustainable substitute of lime to precipitate as ettringite for treatment of selenite/selenate in aqueous solution
AU - Guo, Binglin
AU - Tian, Quanzhi
AU - Oji, Tsubasa
AU - Wang, Lei
AU - Sasaki, Keiko
N1 - Funding Information:
The authors acknowledge the financial support of the Japan Society for the Promotion of Science (JSPS) KAKENHI (A) (No. JP19H00883) and the Alexander von Humboldt Foundation for this study. The EXAFS observation was performed at Kyushu University Beamline (SAGA-LS /BL06) with the proposal No. 2018IIIK001.
Funding Information:
The authors acknowledge the financial support of the Japan Society for the Promotion of Science (JSPS) KAKENHI (A) (No. JP19H00883 ) and the Alexander von Humboldt Foundation for this study. The EXAFS observation was performed at Kyushu University Beamline ( SAGA-LS /BL06 ) with the proposal No. 2018IIIK001.
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2021/2/5
Y1 - 2021/2/5
N2 - The elevated level of selenium (Se) in the aqueous system presents long-term ecological risks. Hydroxylated calcined dolomites (HCDs) are considered as potentially sustainable lime sources due to their lower production temperatures and resourceful than lime. In this study, HCDs were developed for the removal of Se contaminated water. The HCDs exhibited a better performance to co-precipitate with Se oxyanions than pure Ca(OH)2. Considering that HCDs consisted of Ca(OH)2 with MgO and Mg(OH)2, the function of Mg compounds was also elaborated by various characterization techniques. Mg compounds were proved to enhance the precipitation process and Se removal. STEM-EDX observation revealed that SeO32– was incorporated into the ettringite structure with Mg compounds, whereas SeO42– exhibited a affinity to Mg compounds. Extended X-ray absorption fine structure (EXAFS) results for the MgO/Mg(OH)2 after the reaction proved that both SeO32– interacted with Mg(OH)2 and MgO via inner-sphere complexes whereas SeO42– formed outer-sphere complexes with these Mg compounds. Besides, Mg compounds also influenced the surface charge of solid residues and thus enhanced SeO32– removal. This study provides a fundamental understanding of the roles of Mg compounds in the removal of Se oxyanions during environmental remediation. Besides, the HCDs were proved to be sustainable Ca sources for waste/wastewater remediation.
AB - The elevated level of selenium (Se) in the aqueous system presents long-term ecological risks. Hydroxylated calcined dolomites (HCDs) are considered as potentially sustainable lime sources due to their lower production temperatures and resourceful than lime. In this study, HCDs were developed for the removal of Se contaminated water. The HCDs exhibited a better performance to co-precipitate with Se oxyanions than pure Ca(OH)2. Considering that HCDs consisted of Ca(OH)2 with MgO and Mg(OH)2, the function of Mg compounds was also elaborated by various characterization techniques. Mg compounds were proved to enhance the precipitation process and Se removal. STEM-EDX observation revealed that SeO32– was incorporated into the ettringite structure with Mg compounds, whereas SeO42– exhibited a affinity to Mg compounds. Extended X-ray absorption fine structure (EXAFS) results for the MgO/Mg(OH)2 after the reaction proved that both SeO32– interacted with Mg(OH)2 and MgO via inner-sphere complexes whereas SeO42– formed outer-sphere complexes with these Mg compounds. Besides, Mg compounds also influenced the surface charge of solid residues and thus enhanced SeO32– removal. This study provides a fundamental understanding of the roles of Mg compounds in the removal of Se oxyanions during environmental remediation. Besides, the HCDs were proved to be sustainable Ca sources for waste/wastewater remediation.
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U2 - 10.1016/j.colsurfa.2020.125782
DO - 10.1016/j.colsurfa.2020.125782
M3 - Article
AN - SCOPUS:85097083150
SN - 0927-7757
VL - 610
JO - Colloids and Surfaces A: Physicochemical and Engineering Aspects
JF - Colloids and Surfaces A: Physicochemical and Engineering Aspects
M1 - 125782
ER -