Membrane performance of pressure-retarded osmosis using simulated hydroxide-based CO2-captured draw solutions
This study proposes a novel hybrid process that integrates direct air capture (DAC) and pressure-retarded osmosis (PRO) to address high water and energy demands of the DAC process and achieve simultaneous decarbonization and energy production. To explore the PRO performance in this hybrid process, m...
| Main Authors: | , , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
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2024
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| Online Access: | https://hdl.handle.net/10356/180132 |
| _version_ | 1811689073199284224 |
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| author | Guan, Lingxue Li, Tian Krantz, William B. Chong, Tzyy Haur Wu, Bing |
| author2 | School of Civil and Environmental Engineering |
| author_facet | School of Civil and Environmental Engineering Guan, Lingxue Li, Tian Krantz, William B. Chong, Tzyy Haur Wu, Bing |
| author_sort | Guan, Lingxue |
| collection | NTU |
| description | This study proposes a novel hybrid process that integrates direct air capture (DAC) and pressure-retarded osmosis (PRO) to address high water and energy demands of the DAC process and achieve simultaneous decarbonization and energy production. To explore the PRO performance in this hybrid process, membrane fouling behaviors were investigated by employing forward osmosis membranes in the PRO mode with various Na- and K-based draw solutions that simulated hydroxide-based CO2-captured solutions. Especially calcium (Ca2+) and alginate were dosed into the draw solutions as representatives of scaling precursor and organic foulants during long-term DAC-PRO operation respectively. The results revealed that (1) the presence of calcium in the NaHCO3 and KHCO3 draw solutions formed CaCO3 precipitates, whose amounts, morphologies, and particle size were associated with the dosed Ca2+ concentration and alkali solution type. (2) Higher calcium amounts in the NaHCO3 and KHCO3 draw solutions promoted more deposition of rhombohedral CaCO3 crystals on the membrane, leading to a lower water flux (Jw) and higher reverse salt flux (Js) due to increased hydraulic resistance and cake-layer-enhanced concentration polarization. (3) Dosing calcium (40 mM) into a mixture of HCO3- and CO32- draw solution resulted in accumulation of irregular-shape CaCO3 crystals on the membrane and an increase of Jw, possibly relating to the increased membrane hydrophilicity due to decreased solubility of the solute at a higher pH level. (4) The addition of alginate into calcium-dosed (40 mM) draw solutions did not influence Jw and Js but increased deposited foulants. This suggests that deposited alginate may loosely attach to CaCO3 crystals, instead of creating a dense fouling layer by bridging with Ca2+. |
| first_indexed | 2024-10-01T05:42:18Z |
| format | Journal Article |
| id | ntu-10356/180132 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T05:42:18Z |
| publishDate | 2024 |
| record_format | dspace |
| spelling | ntu-10356/1801322024-09-18T05:36:27Z Membrane performance of pressure-retarded osmosis using simulated hydroxide-based CO2-captured draw solutions Guan, Lingxue Li, Tian Krantz, William B. Chong, Tzyy Haur Wu, Bing School of Civil and Environmental Engineering Singapore Membrane Technology Centre Nanyang Environment and Water Research Institute Engineering Alginate Direct air capture This study proposes a novel hybrid process that integrates direct air capture (DAC) and pressure-retarded osmosis (PRO) to address high water and energy demands of the DAC process and achieve simultaneous decarbonization and energy production. To explore the PRO performance in this hybrid process, membrane fouling behaviors were investigated by employing forward osmosis membranes in the PRO mode with various Na- and K-based draw solutions that simulated hydroxide-based CO2-captured solutions. Especially calcium (Ca2+) and alginate were dosed into the draw solutions as representatives of scaling precursor and organic foulants during long-term DAC-PRO operation respectively. The results revealed that (1) the presence of calcium in the NaHCO3 and KHCO3 draw solutions formed CaCO3 precipitates, whose amounts, morphologies, and particle size were associated with the dosed Ca2+ concentration and alkali solution type. (2) Higher calcium amounts in the NaHCO3 and KHCO3 draw solutions promoted more deposition of rhombohedral CaCO3 crystals on the membrane, leading to a lower water flux (Jw) and higher reverse salt flux (Js) due to increased hydraulic resistance and cake-layer-enhanced concentration polarization. (3) Dosing calcium (40 mM) into a mixture of HCO3- and CO32- draw solution resulted in accumulation of irregular-shape CaCO3 crystals on the membrane and an increase of Jw, possibly relating to the increased membrane hydrophilicity due to decreased solubility of the solute at a higher pH level. (4) The addition of alginate into calcium-dosed (40 mM) draw solutions did not influence Jw and Js but increased deposited foulants. This suggests that deposited alginate may loosely attach to CaCO3 crystals, instead of creating a dense fouling layer by bridging with Ca2+. This study was supported by the Landsvirkjun Energy Research Fund in Iceland (grant number: NÝR-05-2022) and the University of Iceland Research Fund. Lingxue Guan thanks the Eimskip University Fund to provide her PhD scholarship. 2024-09-18T05:36:27Z 2024-09-18T05:36:27Z 2024 Journal Article Guan, L., Li, T., Krantz, W. B., Chong, T. H. & Wu, B. (2024). Membrane performance of pressure-retarded osmosis using simulated hydroxide-based CO2-captured draw solutions. Separation and Purification Technology, 339, 126699-. https://dx.doi.org/10.1016/j.seppur.2024.126699 1383-5866 https://hdl.handle.net/10356/180132 10.1016/j.seppur.2024.126699 2-s2.0-85184743182 339 126699 en Separation and Purification Technology © 2024 Elsevier B.V. All rights reserved. |
| spellingShingle | Engineering Alginate Direct air capture Guan, Lingxue Li, Tian Krantz, William B. Chong, Tzyy Haur Wu, Bing Membrane performance of pressure-retarded osmosis using simulated hydroxide-based CO2-captured draw solutions |
| title | Membrane performance of pressure-retarded osmosis using simulated hydroxide-based CO2-captured draw solutions |
| title_full | Membrane performance of pressure-retarded osmosis using simulated hydroxide-based CO2-captured draw solutions |
| title_fullStr | Membrane performance of pressure-retarded osmosis using simulated hydroxide-based CO2-captured draw solutions |
| title_full_unstemmed | Membrane performance of pressure-retarded osmosis using simulated hydroxide-based CO2-captured draw solutions |
| title_short | Membrane performance of pressure-retarded osmosis using simulated hydroxide-based CO2-captured draw solutions |
| title_sort | membrane performance of pressure retarded osmosis using simulated hydroxide based co2 captured draw solutions |
| topic | Engineering Alginate Direct air capture |
| url | https://hdl.handle.net/10356/180132 |
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