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Enhanced boron removal via seed-induced crystal growth of barium perborate in sequential fluidized-bed crystallization.
- Source :
-
Chemosphere [Chemosphere] 2024 Aug; Vol. 361, pp. 142569. Date of Electronic Publication: 2024 Jun 07. - Publication Year :
- 2024
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Abstract
- Chemical oxo-precipitation (COP) is an enhanced precipitation method for boron removal with the conversion of boric acid to perborate anions. When using barium-based precipitant, the boron can be effectively precipitated as barium perborates (BaPBs). The phase transformation of BaPBs from amorphous (A-BaPB, Ba(B(OH) <subscript>3</subscript> OOH) <subscript>2</subscript> ) to crystalline (C-BaPB, BaB <subscript>2</subscript> (OO) <subscript>2</subscript> (OH) <subscript>4</subscript> ) form is crucial for effective boron removal. However, scaling up this phase transformation of BaPBs is hindered by poor diffusion. This study aims to promote the growth of C-BaPB through seed-induced crystal growth, eliminating the need for phase transformation. By examining the relationship between crystal growth rate and supersaturation, surface spiral growth was identified as the rate-limiting step of the growth of micron-sized seeds near pH <subscript>pzc</subscript> . To enable continuous crystal growth, granular seeds of C-BaPB were prepared and employed as the medium for fluidized-bed crystallization (FBC). The system reached steady state 3 hydraulic retention times, achieving 90% boron removal. The effect of surface loading, ionic strength, and dosages on steady-state crystal growth rate was studied, revealing a shift of the rate-limiting step in FBC to diffusion. Lastly, the system that constituted of two FBCs in-series for sequential crystallization of A-BaPB and C-BaPB was demonstrated. The integrated system provided 97.8% of boron removal from synthetic wastewater containing 500 mg-B/L, with 92.3% of boron crystallized on the granular seeds of BaPBs.<br />Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.<br /> (Copyright © 2024 Elsevier Ltd. All rights reserved.)
Details
- Language :
- English
- ISSN :
- 1879-1298
- Volume :
- 361
- Database :
- MEDLINE
- Journal :
- Chemosphere
- Publication Type :
- Academic Journal
- Accession number :
- 38852627
- Full Text :
- https://doi.org/10.1016/j.chemosphere.2024.142569