Unraveling the Potential of Electrochemical pH-Swing Processes for Carbon Dioxide Capture and Utilization

Cao, Thanh Ngoc-Dan; Snyder, Seth W; Lin, Yu-I; Lin, Yupo J; Negi, Suraj; Pan, Shu-Yuan

doi:10.1021/acs.iecr.3c02183

Cited by 5 publications

(4 citation statements)

References 80 publications

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“…Ideal cycle energy is found to be as low as around 250 kJ/mol for certain operating regimes, although it is expected that higher energy will be required if higher cycle capacity is desirable. For context, redox electrochemical DAC processes have been shown to reach 100 kJ/mol on bench scale systems, and industrial solid sorbent and calcium-looping processes can reach energy requirements lower than 300 kJ/mol . To reach similar or lower energy levels, energy recovery modules that recover energy from the salinity differences created through the NF and RO modules can significantly reduce the energy cost of capture.…”

Section: Resultsmentioning

confidence: 99%

“…The NF selectivity results that we report in this work are also directly applicable to approaches beyond DAC and are useful for any method that seeks to control the relative concentration of DIC species in solution. In particular, recent studies have reported that bicarbonate-rich solution can be used as a feed for electrolytic conversion to useful chemicals. ,,, For example, Lees et al (2020) describe a process that captures CO 2 from the atmosphere or flue gas and uses electrolyzers to convert a 3 M KHCO3 solution into CO . However, the step between CO 2 absorption, which must happen at high pH conditions and therefore is dominated by carbonate ions, and the bicarbonate-rich end point is not explored.…”

Section: Resultsmentioning

confidence: 99%

“…This work builds on the body of research of aqueous solvent DAC approaches, which has recently been focused on electrochemical methods. − Electrochemical DAC has the advantage of feasibly reaching low energy of capture, below 100 kJ/mol; however, the various approaches still face implementation challenges relating to chemical degradation, membrane stability and fouling, low kinetics of reaction, and more …”

Section: Introductionmentioning

confidence: 99%

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Bicarbonate-Carbonate Selectivity through Nanofiltration for Direct Air Capture of Carbon Dioxide

Rinberg,

Aziz

2024

ACS EST Eng.

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Direct air capture (DAC) of carbon dioxide is one approach among many proposed that is capable of offsetting hardto-avoid emissions. In previous work, we developed the alkalinity concentration swing (ACS) method, which is driven through concentrating an alkaline solution that has been loaded with atmospheric CO 2 by desalination technologies, such as reverse osmosis or capacitive deionization. Though the ACS is promising in terms of energy usage and implementation, its absorption rate and water requirements are infeasible for a large-scale DAC process. Here, we propose an improvement on the ACS, the bicarbonate-enriched alkalinity concentration swing (BE-ACS), which selects bicarbonate ions from a stream of aqueous alkaline solution that has absorbed atmospheric CO 2 . The bicarbonate-rich stream is then concentrated, which greatly increases its CO 2 partial pressure, and then CO 2 is extracted from solution. We experimentally investigate the use of pressure-driven nanofiltration (NF) membrane-based separation to select bicarbonate ions over carbonate ions. We screen commercial membranes and select one high-performance membrane for detailed studies, quantifying its bicarbonate-carbonate selectivity factor and bicarbonate-passage factor. Feed pH, the combined concentration of aqueous CO 2 , bicarbonate, and carbonate species (or dissolved inorganic carbon), alkalinity, and permeation flux are systematically varied to study NF separation properties. We find that the selectivity factor, which exceeds 30 times in certain regimes, increases with higher feed pH and higher alkalinity. The performance metrics of the selected NF membrane are input into a theoretical BE-ACS cycle analysis, and the required energy input and cycle capacity output are evaluated. Ideal cycle energy is found to be as low as around 250 kJ/mol, with opportunities identified for further decreases through process engineering and forward osmosis energy recovery.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Bicarbonate-Carbonate Selectivity through Nanofiltration for Direct Air Capture of Carbon Dioxide

Rinberg,

Aziz

2024

ACS EST Eng.

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“…Subsequently, the excess acid is removed to regenerate the starting sorbent. This process is known as pH swing desorption and is typically achieved by dialysis or by modulating the pH using a spectator analyte. − …”

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confidence: 99%

Photoinduced Carbon Dioxide Release via a Metastable Photoacid in a Nonaqueous Environment

Cotton,

Khuu,

Takematsu

et al. 2024

J. Phys. Chem. Lett.

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Capturing carbon dioxide (CO 2 ) from the atmosphere is a scientific and technological challenge. CO 2 can be captured by forming carbamate bonds with amines, most notably monoethanolamine (MEA). Regenerating MEA by releasing captured CO 2 requires that the carbamate solution be heated. Recently, photoacids were used to induce a pH change to release CO 2 from aqueous carbonate solutions. We report a merocyanine photoacid that releases CO 2 from nonaqueous carbamate solutions of MEA, which has a CO 2 loading capacity that is higher than that of water. On the basis of the absorption spectra of the photoacid in the presence of acids and CO 2 , we show that the photoacid cycle and the CO 2 capture of MEA are two separate equilibria coupled to each other via protons. We demonstrate that irradiating the sample with 405 nm light induces the release of CO 2 , which we detect using an in-line mass spectrometer. This work highlights an alternative path for optimizing a photoinduced CO 2 capture and release system.Letter pubs.acs.org/JPCL

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Electrodialysis as a key operating unit in chemical processes: From lab to pilot scale of latest breakthroughs

Hopsort,

Cacciuttolo,

Pasquier

2024

Chemical Engineering Journal

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Unraveling the Potential of Electrochemical pH-Swing Processes for Carbon Dioxide Capture and Utilization

Cited by 5 publications

References 80 publications

Bicarbonate-Carbonate Selectivity through Nanofiltration for Direct Air Capture of Carbon Dioxide

Bicarbonate-Carbonate Selectivity through Nanofiltration for Direct Air Capture of Carbon Dioxide

Photoinduced Carbon Dioxide Release via a Metastable Photoacid in a Nonaqueous Environment

Electrodialysis as a key operating unit in chemical processes: From lab to pilot scale of latest breakthroughs

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