Boron incorporation into precipitated calcium carbonates affected by aqueous pH and boron concentration.

Author(s) Kobayashi, K.; Hashimoto, Y.; Wang, S.L.
Journal J Hazard Mater
Date Published 2020 Feb 05
Abstract

The objectives of this study were to investigate the amount of B incorporation into precipitated calcium carbonate (PCC) in the coprecipitation process, and to determine specific mineral phases (calcite or vaterite) and the mode of B coordination (trigonal or tetrahedral) in PCC under different pH and B concentrations. The amount of B incorporation into PCC increased in general with increasing aqueous B (B) concentrations in the pH range from 8 to 12. The B removal by PCC reached maximum (∼200 mmol kg) at pH 10 with B concentrations between 30 and 50 mM. The transformation of vaterite to calcite was promoted with increasing B at pH 8 and 10, whereas an excess concentration of aqueous (poly)borate anions (100 mM) inhibited crystal growth of calcite. As determined by B K-edge X-ray absorption fine structure spectroscopy, the coordination of B incorporated in PCC was preferentially tetrahedral (B, 55-70%) over trigonal (B, 30-45%) at B <75 mM. In contrast, the preferential incorporation of B into PCC was not observed in the solution with a high B concentration (i.e., 100 mM). The amount of B incorporation, the morphology of PCC and B coordination in PCC were remarkably changed in high B concentrations.

DOI 10.1016/j.jhazmat.2019.121183
ISSN 1873-3336
Citation J Hazard Mater. 2020;383:121183.

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