EGU23-6320
https://doi.org/10.5194/egusphere-egu23-6320
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Freezing-induced bromate reduction through iodide and its implications

Quoc Anh Nguyen1,2 and Kitae Kim1,2
Quoc Anh Nguyen and Kitae Kim
  • 1Korea Polar Research Institute, Research Unit of Cryogenic Novel Material, Korea, Republic of (quocanh@kopri.re.kr)
  • 2Department of Polar Sciences, University of Science and Technology (UST), Incheon 21990, Republic of Korea.

Freezing, which is the naturally facile process in the cold climate regions, has been extensively investigated as a non-contamination and effective cost method in the environmental treatment. The reactive halogens chemistry has a huge impact on the global environment, especially polar regions. Here, we elucidated the generation of iodine (I2), tri-iodide (I3-), and bromide (Br-) through the bromate (BrO3-) reduction by iodide (I-) in the unfrozen solution of ice while it did not take place in aqueous solution. This appreciably enhanced transformation was attributed majorly to the freeze concentration effect of BrO3-, I-, and protons (H+) in the liquid boundary of ice. The ice grain boundary regions created as well as the consumption of BrO3- in the BrO3-/I-/freezing systemin those regions during freezing were visualized with the confocal Raman microscope. pH decrease (the accumulation of H+) during freezing was measured quantitatively by the UV-Vis absorption spectra of cresol red (as the acid-base indicator). Also, the freeze concentration effect of I- on the BrO3- transformation was verified in the differently experimental conditions of pH and/ or I- concentration. The study on the acceleration of BrO3-/I-/freezing system provides not only an unknown production pathway of bromine and iodine speciation in the polar environment but also the environmentally friendly insight into BrO3- treatment (known as the disinfection byproduct during ozonation in water treatment). 

How to cite: Nguyen, Q. A. and Kim, K.: Freezing-induced bromate reduction through iodide and its implications, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-6320, https://doi.org/10.5194/egusphere-egu23-6320, 2023.

Supplementary materials

Supplementary material file