Given that mining to extract high-grade mineral ores is wastefully energy intensive, exhaustible, and bad for the environment, scientists have been scouting for alternatives. A group of Korean researchers, led by Professor Myoung-Jin Kim, from Korea Maritime and Ocean University, have now succeeded in extracting high-quality minerals from just seawater. Specifically, they have achieved the extraction of 99.8% pure magnesium sulphate (MgSO4), from seawater desalination brine (SDB).
Speaking about the motivation behind the study, Prof. Kim exclaims, "Since we have already developed a sophisticated seawater desalination process to address the world's water needs, why not couple it with the beneficial process of mineral extraction! In this way, we believe that such extraction can be performed in an energy-efficient, sustainable, and environment-friendly manner." The team's findings have been published online, as a research article, on 15th December 2021, in Volume 518 of the journal Desalination.
Further, the team has not only coupled the two processes, but has also developed a novel and subtle ethanol-based process to extract MgSO4. Initially, the researchers followed steps such as alkali-based magnesium hydroxide pre-precipitation from brine, and sulfuric acid-based magnesium concentration. Finally, they treated the magnesium eluate, twice, with ethanol—the first time, to remove calcium impurities, and the second time, to precipitate the high-purity MgSO4. Interestingly, this final two-stepprocess used the difference in solubility between magnesium and calcium sulphates in ethanol, to achieve up to 67% magnesium recovery efficiency.
Owing to the cost-effectiveness of mineral extraction from SDB, the researchers state that the obtained MgSO4 may not only be used for re-mineralizing desalinated fresh water, but also find potential applications in the pharmaceutical and food industry. Prof. Kim adds, "We hope that our study encourages further research on alternative mineral extraction processes."
Indeed, humanity, with the aid of such science, can hope to reverse environmental damage, while sustainably meeting its needs for continued technological advancements.
Reference
Authors: Myoung-Jin Kim1,2, Sehun Kim3, Seonmi Shin1,2, and Geunyoung Kim1,2
Title of original paper: Production of high-purity MgSO4 from seawater desalination brine
Journal: Desalination
DOI: https://doi.org/10.1016/j.desal.2021.115288
Affiliations:
- Department of Environmental Engineering, Korea Maritime and Ocean University, Republic of Korea
- Interdisciplinary Major of Ocean Renewable Energy Engineering, Korea Maritime and Ocean University, Republic of Korea
- Department of Convergence Study on the Ocean Science and Technology, Korea Maritime and Ocean University, Republic of Korea
About National Korea Maritime & Ocean University
South Korea's most prestigious university for maritime studies, transportation science and engineering, the National Korea Maritime & Ocean University is located on an island in Busan. The university was established in 1945 and since then has merged with other universities to currently being the only post-secondary institution that specializes in maritime sciences and engineering. It has four colleges that offer both undergraduate and graduate courses.
Website: http://www.kmou.ac.kr/english/main.do
About Dr. Myoung-Jin Kim
Dr. Myoung-Jin Kim is a Professor of Environmental Engineering at the Korea Maritime and Ocean University. Professor Kim' is interested in developing technologies to store carbon dioxide and produce calcium carbonate through indirect carbonation; and economically recovering high-purity magnesium compounds from seawater. She received her PhD in Environmental Health Sciences from the University of Michigan, USA, in 1999. She has authored more than 35 research publications, in internationally reputed journals.
