TY - JOUR
T1 - Selective electrochemical separation and recovery of calcium and magnesium from brine
AU - Lalia, Boor Singh
AU - Khalil, Abdullah
AU - Hashaikeh, Raed
N1 - Funding Information:
This work was supported by the NYUAD Water Research Center, funded by Tamkeen under the NYUAD Research Institute Award (project CG007). The authors would like to thank Core Technology Platform at New York University, Abu Dhabi for providing SEM and XRD facilities.
Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/6/1
Y1 - 2021/6/1
N2 - Desalination via reverse osmosis (RO) generates a stream of fresh water and an almost equivalent volume of highly concentrated brine as waste. The waste brine is usually disposed back to the sea which increases the sea salinity in a way that can affect the marine life. Treatment of this waste brine is vital for the environment. The treatment process can be made feasible by extracting value added products from this waste brine. In this context, the current study demonstrates a novel two-step electrochemical process for selective separation and recovery of calcium and magnesium from brine. The first step involves purging carbon dioxide in the brine solution while electrochemically precipitating calcite using titania coated graphite cathode and pristine graphite anode at an applied potential of 2.5 V. The use of titania coated surface was found to be effective in promoting selective calcite precipitation. After calcite removal, brucite is selectively precipitated using pristine graphite cathode and anode at an applied potential of 3.5 V. This study also reveals the importance of DC potential and the electrode material for selective precipitation of calcium and magnesium ions from brine. Ion chromatography was used to analyze the concentration of calcium and magnesium ions in the treated and non-treated brine. X-ray diffraction and scanning electron microscopy of electrode precipitates confirmed the removal of calcium and magnesium from brine as calcite and brucite, respectively. Besides reducing the brine salinity, the developed process yields two separate compounds which can be further converted into calcium and magnesium-based products for several commercial applications.
AB - Desalination via reverse osmosis (RO) generates a stream of fresh water and an almost equivalent volume of highly concentrated brine as waste. The waste brine is usually disposed back to the sea which increases the sea salinity in a way that can affect the marine life. Treatment of this waste brine is vital for the environment. The treatment process can be made feasible by extracting value added products from this waste brine. In this context, the current study demonstrates a novel two-step electrochemical process for selective separation and recovery of calcium and magnesium from brine. The first step involves purging carbon dioxide in the brine solution while electrochemically precipitating calcite using titania coated graphite cathode and pristine graphite anode at an applied potential of 2.5 V. The use of titania coated surface was found to be effective in promoting selective calcite precipitation. After calcite removal, brucite is selectively precipitated using pristine graphite cathode and anode at an applied potential of 3.5 V. This study also reveals the importance of DC potential and the electrode material for selective precipitation of calcium and magnesium ions from brine. Ion chromatography was used to analyze the concentration of calcium and magnesium ions in the treated and non-treated brine. X-ray diffraction and scanning electron microscopy of electrode precipitates confirmed the removal of calcium and magnesium from brine as calcite and brucite, respectively. Besides reducing the brine salinity, the developed process yields two separate compounds which can be further converted into calcium and magnesium-based products for several commercial applications.
KW - Carbon dioxide sequestration
KW - Magnesium recovery
KW - Reverse osmosis
KW - Selective electrochemical precipitation
KW - Waste brine treatment
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U2 - 10.1016/j.seppur.2021.118416
DO - 10.1016/j.seppur.2021.118416
M3 - Article
AN - SCOPUS:85100615350
SN - 1383-5866
VL - 264
JO - Separation and Purification Technology
JF - Separation and Purification Technology
M1 - 118416
ER -