Dissecting the structure-compaction-performance relationship of thin-film composite polyamide membranes with different structure features
Thin film composite (TFC) polyamide (PA) membranes experience compaction at high pressure applications, resulting in the reduction in water permeability. However, the compaction mechanism is still unclear especially for different PA morphologies and substrate structures. In this work, we systematica...
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2022
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| Online Access: | https://hdl.handle.net/10356/161963 |
| _version_ | 1824455860132249600 |
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| author | Zhao, Yali Lai, Gwo Sung Chong, Jeng Yi Wang, Rong |
| author2 | School of Civil and Environmental Engineering |
| author_facet | School of Civil and Environmental Engineering Zhao, Yali Lai, Gwo Sung Chong, Jeng Yi Wang, Rong |
| author_sort | Zhao, Yali |
| collection | NTU |
| description | Thin film composite (TFC) polyamide (PA) membranes experience compaction at high pressure applications, resulting in the reduction in water permeability. However, the compaction mechanism is still unclear especially for different PA morphologies and substrate structures. In this work, we systematically studied the compaction of TFC PA membranes with different structures and morphologies. We first examined 2 main types of commercial reverse osmosis (RO) membranes: brackish water RO and seawater RO membranes. After that, we synthesised four types of TFC membranes with tailored PA and substrate structures to further understand the compaction behaviors. TFC membrane with a PA layer of low protuberances or nodules and dense substrate showed excellent resistance against high pressure (50 bar), with only a slight irreversible decrease of 2.1–3.5% in water permeability when retested at 5 bar. However, the PA layer of high protuberances experienced significant compaction even when it was supported by a similar dense substrate. The permeability of the TFC membrane decreased ∼10% as a result of the decrease in the effective area of the active layer. On the other hand, the TFC membrane with a PA layer of low protuberances formed atop a loose substrate showed a greater decrease (∼18.5%) in water permeability. The densified skin layer and collapsed macro-voids within the loose substrate resulted in a ∼40% decrease in the overall height of the PA layer and a 65% decline in substrate surface porosity, respectively, which are identified as the reasons for the reducing water permeability. Notably, the water-salt selectivity of this particular membrane was seriously deteriorated after compaction due to the presence of subtle defects in the PA layer caused by the drastic deformation of the loose substrate. This work deepens the understanding of the compaction behaviors of TFC PA membranes, providing a clear fundamental guidance on designing membranes applied at high operating pressures. |
| first_indexed | 2025-02-19T03:44:55Z |
| format | Journal Article |
| id | ntu-10356/161963 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2025-02-19T03:44:55Z |
| publishDate | 2022 |
| record_format | dspace |
| spelling | ntu-10356/1619632022-09-27T07:35:44Z Dissecting the structure-compaction-performance relationship of thin-film composite polyamide membranes with different structure features Zhao, Yali Lai, Gwo Sung Chong, Jeng Yi Wang, Rong School of Civil and Environmental Engineering Nanyang Environment and Water Research Institute Singapore Membrane Technology Centre Engineering::Environmental engineering Membrane Compaction Substrate Structure Thin film composite (TFC) polyamide (PA) membranes experience compaction at high pressure applications, resulting in the reduction in water permeability. However, the compaction mechanism is still unclear especially for different PA morphologies and substrate structures. In this work, we systematically studied the compaction of TFC PA membranes with different structures and morphologies. We first examined 2 main types of commercial reverse osmosis (RO) membranes: brackish water RO and seawater RO membranes. After that, we synthesised four types of TFC membranes with tailored PA and substrate structures to further understand the compaction behaviors. TFC membrane with a PA layer of low protuberances or nodules and dense substrate showed excellent resistance against high pressure (50 bar), with only a slight irreversible decrease of 2.1–3.5% in water permeability when retested at 5 bar. However, the PA layer of high protuberances experienced significant compaction even when it was supported by a similar dense substrate. The permeability of the TFC membrane decreased ∼10% as a result of the decrease in the effective area of the active layer. On the other hand, the TFC membrane with a PA layer of low protuberances formed atop a loose substrate showed a greater decrease (∼18.5%) in water permeability. The densified skin layer and collapsed macro-voids within the loose substrate resulted in a ∼40% decrease in the overall height of the PA layer and a 65% decline in substrate surface porosity, respectively, which are identified as the reasons for the reducing water permeability. Notably, the water-salt selectivity of this particular membrane was seriously deteriorated after compaction due to the presence of subtle defects in the PA layer caused by the drastic deformation of the loose substrate. This work deepens the understanding of the compaction behaviors of TFC PA membranes, providing a clear fundamental guidance on designing membranes applied at high operating pressures. National Research Foundation (NRF) Public Utilities Board (PUB) This research is supported by the National Research Foundation, Singapore, and PUB, Singapore’s national water agency under the Unban Solutions & Sustainability program (project number PUB-1801-0010). 2022-09-27T07:35:43Z 2022-09-27T07:35:43Z 2022 Journal Article Zhao, Y., Lai, G. S., Chong, J. Y. & Wang, R. (2022). Dissecting the structure-compaction-performance relationship of thin-film composite polyamide membranes with different structure features. Journal of Membrane Science, 654, 120553-. https://dx.doi.org/10.1016/j.memsci.2022.120553 0376-7388 https://hdl.handle.net/10356/161963 10.1016/j.memsci.2022.120553 2-s2.0-85128980679 654 120553 en PUB-1801-0010 Journal of Membrane Science © 2022 Elsevier B.V. All rights reserved. |
| spellingShingle | Engineering::Environmental engineering Membrane Compaction Substrate Structure Zhao, Yali Lai, Gwo Sung Chong, Jeng Yi Wang, Rong Dissecting the structure-compaction-performance relationship of thin-film composite polyamide membranes with different structure features |
| title | Dissecting the structure-compaction-performance relationship of thin-film composite polyamide membranes with different structure features |
| title_full | Dissecting the structure-compaction-performance relationship of thin-film composite polyamide membranes with different structure features |
| title_fullStr | Dissecting the structure-compaction-performance relationship of thin-film composite polyamide membranes with different structure features |
| title_full_unstemmed | Dissecting the structure-compaction-performance relationship of thin-film composite polyamide membranes with different structure features |
| title_short | Dissecting the structure-compaction-performance relationship of thin-film composite polyamide membranes with different structure features |
| title_sort | dissecting the structure compaction performance relationship of thin film composite polyamide membranes with different structure features |
| topic | Engineering::Environmental engineering Membrane Compaction Substrate Structure |
| url | https://hdl.handle.net/10356/161963 |
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