Influence of the sublayer structure of thin-film composite reverse osmosis membranes on the overall water flux

Jaewoo Lee, Hongsik Yoon, Jae Hyun Yoo, Dong Chan Choi, Chang H. Nahm, Sang Hyun Lee, Hee Ro Chae, Yong Hyup Kim, Chung Hak Lee, Pyung Kyu Park

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We found that a support layer of a reverse osmosis (RO) membrane could have a significant effect on the membrane filtration efficiency. To be specific, we determined that the pressure drop occurring in the support layer during the RO operation can increase such that it affects the overall water flux, as a dense sponge-like structure and closed finger-like structure become predominant in the support layer. This considerable resistance was assumed to occur while more water passes through tortuous and segmented regions after being evenly discharged from the active layer. This hypothesis was supported by the estimated pressure drop using the Ergun equation and the tortuosity obtained from a forward osmosis test conducted to better reflect the influence of the sponge-like region. We attempted to factor in all of the parameters used in the Ergun equation in order to determine the main cause of the high pressure drop, and the tortuosity was found to be dominant. An interesting finding was that the tortuosity of the support layer can also significantly influence the overall water flux, even during the RO process. Moreover, the above phenomenon can become much more obvious when the active layer is highly permeable, suggesting that the support layer must be considered alongside the active layer when developing thin-film composite membranes with a highly permeable active layer. Overall, we concluded that the concentration of the polymer solution should be less than 20 wt% to ensure the best performance when preparing a support layer for brackish-water RO membranes.

Original languageEnglish
Pages (from-to)1912-1922
Number of pages11
JournalEnvironmental Science: Water Research and Technology
Volume4
Issue number12
DOIs
Publication statusPublished - 2018 Dec

Fingerprint

Osmosis membranes
Reverse osmosis
active layer
Fluxes
membrane
Pressure drop
Thin films
tortuosity
Composite materials
pressure drop
Water
sponge
water
Osmosis
Composite membranes
Polymer solutions
Membranes
osmosis
brackish water
reverse osmosis

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Water Science and Technology

Cite this

Lee, Jaewoo ; Yoon, Hongsik ; Yoo, Jae Hyun ; Choi, Dong Chan ; Nahm, Chang H. ; Lee, Sang Hyun ; Chae, Hee Ro ; Kim, Yong Hyup ; Lee, Chung Hak ; Park, Pyung Kyu. / Influence of the sublayer structure of thin-film composite reverse osmosis membranes on the overall water flux. In: Environmental Science: Water Research and Technology. 2018 ; Vol. 4, No. 12. pp. 1912-1922.
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Influence of the sublayer structure of thin-film composite reverse osmosis membranes on the overall water flux. / Lee, Jaewoo; Yoon, Hongsik; Yoo, Jae Hyun; Choi, Dong Chan; Nahm, Chang H.; Lee, Sang Hyun; Chae, Hee Ro; Kim, Yong Hyup; Lee, Chung Hak; Park, Pyung Kyu.

In: Environmental Science: Water Research and Technology, Vol. 4, No. 12, 12.2018, p. 1912-1922.

Research output: Contribution to journalArticle

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T1 - Influence of the sublayer structure of thin-film composite reverse osmosis membranes on the overall water flux

AU - Lee, Jaewoo

AU - Yoon, Hongsik

AU - Yoo, Jae Hyun

AU - Choi, Dong Chan

AU - Nahm, Chang H.

AU - Lee, Sang Hyun

AU - Chae, Hee Ro

AU - Kim, Yong Hyup

AU - Lee, Chung Hak

AU - Park, Pyung Kyu

PY - 2018/12

Y1 - 2018/12

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AB - We found that a support layer of a reverse osmosis (RO) membrane could have a significant effect on the membrane filtration efficiency. To be specific, we determined that the pressure drop occurring in the support layer during the RO operation can increase such that it affects the overall water flux, as a dense sponge-like structure and closed finger-like structure become predominant in the support layer. This considerable resistance was assumed to occur while more water passes through tortuous and segmented regions after being evenly discharged from the active layer. This hypothesis was supported by the estimated pressure drop using the Ergun equation and the tortuosity obtained from a forward osmosis test conducted to better reflect the influence of the sponge-like region. We attempted to factor in all of the parameters used in the Ergun equation in order to determine the main cause of the high pressure drop, and the tortuosity was found to be dominant. An interesting finding was that the tortuosity of the support layer can also significantly influence the overall water flux, even during the RO process. Moreover, the above phenomenon can become much more obvious when the active layer is highly permeable, suggesting that the support layer must be considered alongside the active layer when developing thin-film composite membranes with a highly permeable active layer. Overall, we concluded that the concentration of the polymer solution should be less than 20 wt% to ensure the best performance when preparing a support layer for brackish-water RO membranes.

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