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

Binglin Guo, Quanzhi Tian, Tsubasa Oji, Lei Wang, Keiko Sasaki

研究成果: Contribution to journalArticle査読

1 被引用数 (Scopus)

抄録

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.

本文言語英語
論文番号125782
ジャーナルColloids and Surfaces A: Physicochemical and Engineering Aspects
610
DOI
出版ステータス出版済み - 2 5 2021

All Science Journal Classification (ASJC) codes

  • 表面および界面
  • 物理化学および理論化学
  • コロイド化学および表面化学

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