Process Intensification for Enhanced Fluoride Removal and Recovery as Calcium Fluoride Using a Fluidized Bed Reactor.

Autor: Sinharoy A; Department of Environmental Science & Biotechnology, Jeonju University, Jeonju 55069, Republic of Korea., Lee GY; Department of Environmental Science & Biotechnology, Jeonju University, Jeonju 55069, Republic of Korea., Chung CM; Department of Environmental Science & Biotechnology, Jeonju University, Jeonju 55069, Republic of Korea.
Jazyk: angličtina
Zdroj: International journal of molecular sciences [Int J Mol Sci] 2024 Apr 24; Vol. 25 (9). Date of Electronic Publication: 2024 Apr 24.
DOI: 10.3390/ijms25094646
Abstrakt: This study explored the feasibility of fluoride removal from simulated semiconductor industry wastewater and its recovery as calcium fluoride using fluidized bed crystallization. The continuous reactor showed the best performance (>90% fluoride removal and >95% crystallization efficiency) at a calcium-to-fluoride ratio of 0.6 within the first 40 days of continuous operation. The resulting particle size increased by more than double during this time, along with a 36% increase in the seed bed height, indicating the deposition of CaF 2 onto the silica seed. The SEM-EDX analysis showed the size and shape of the crystals formed, along with the presence of a high amount of Ca-F ions. The purity of the CaF 2 crystals was determined to be 91.1% though ICP-OES analysis. Following the continuous experiment, different process improvement strategies were explored. The addition of an excess amount of calcium resulted in the removal of an additional 6% of the fluoride; however, compared to this single-stage process, a two-stage approach was found to be a better strategy to achieve a low effluent concentration of fluoride. The fluoride removal reached 94% with this two-stage approach under the optimum conditions of 4 + 1 h HRT combinations and a [Ca 2+ ]/[F - ] ratio of 0.55 and 0.7 for the two reactors, respectively. CFD simulation showed the impact of the inlet diameter, bottom-angle shape, and width-to-height ratio of the reactor on the mixing inside the reactor and the possibility of further improvement in the reactor performance by optimizing the FBR configuration.
Databáze: MEDLINE
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