Permeate Flux in Ultrafiltration Processes—Understandings and Misunderstandings
Concentration polarization refers to the rapid emergence of concentration gradients at a membrane/solution interface resulting from selective transfer through the membrane. It is distinguishable from fouling in at least two ways: (1) the state of the molecules involved (in solution for concentration...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-02-01
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| Series: | Membranes |
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| Online Access: | https://www.mdpi.com/2077-0375/12/2/187 |
| _version_ | 1797478222598766592 |
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| author | Robert W. Field Jun Jie Wu |
| author_facet | Robert W. Field Jun Jie Wu |
| author_sort | Robert W. Field |
| collection | DOAJ |
| description | Concentration polarization refers to the rapid emergence of concentration gradients at a membrane/solution interface resulting from selective transfer through the membrane. It is distinguishable from fouling in at least two ways: (1) the state of the molecules involved (in solution for concentration polarization, although no longer in solution for fouling); and (2) by the timescale, normally less than a minute for concentration polarization, although generally at least two or more orders of magnitude more for fouling. Thus the phenomenon of flux decline occurring over a timescale of tens of minutes should not be attributed to concentration polarization establishing itself. This distinction and a number of questions surrounding modelling are addressed and clarified. There are two paradigmatic approaches for modelling flux, one uses the overall driving force (in which case allowance for osmotic effects are expressed as additional resistances) and the other uses the net driving force across the separating layer or fouled separating layer, although often the two are unfortunately comingled. In the discussion of flux decline models’ robust approaches for the determination of flux-time relationships, including the integral method of fouling analysis, are discussed and various concepts clarified. The final section emphases that for design purposes, pilot plant data are vital. |
| first_indexed | 2024-03-09T21:28:57Z |
| format | Article |
| id | doaj.art-d36887a3c053486bafc7e1ce017cb0cf |
| institution | Directory Open Access Journal |
| issn | 2077-0375 |
| language | English |
| last_indexed | 2024-03-09T21:28:57Z |
| publishDate | 2022-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Membranes |
| spelling | doaj.art-d36887a3c053486bafc7e1ce017cb0cf2023-11-23T21:03:13ZengMDPI AGMembranes2077-03752022-02-0112218710.3390/membranes12020187Permeate Flux in Ultrafiltration Processes—Understandings and MisunderstandingsRobert W. Field0Jun Jie Wu1Faculty of Engineering and Environment, Northumbria University, Newcastle NE1 8ST, UKDepartment of Engineering, Faculty of Science, Durham University, Durham DH1 3LE, UKConcentration polarization refers to the rapid emergence of concentration gradients at a membrane/solution interface resulting from selective transfer through the membrane. It is distinguishable from fouling in at least two ways: (1) the state of the molecules involved (in solution for concentration polarization, although no longer in solution for fouling); and (2) by the timescale, normally less than a minute for concentration polarization, although generally at least two or more orders of magnitude more for fouling. Thus the phenomenon of flux decline occurring over a timescale of tens of minutes should not be attributed to concentration polarization establishing itself. This distinction and a number of questions surrounding modelling are addressed and clarified. There are two paradigmatic approaches for modelling flux, one uses the overall driving force (in which case allowance for osmotic effects are expressed as additional resistances) and the other uses the net driving force across the separating layer or fouled separating layer, although often the two are unfortunately comingled. In the discussion of flux decline models’ robust approaches for the determination of flux-time relationships, including the integral method of fouling analysis, are discussed and various concepts clarified. The final section emphases that for design purposes, pilot plant data are vital.https://www.mdpi.com/2077-0375/12/2/187concentration polarizationosmotic modelfoulingmodes of foulingdesign |
| spellingShingle | Robert W. Field Jun Jie Wu Permeate Flux in Ultrafiltration Processes—Understandings and Misunderstandings Membranes concentration polarization osmotic model fouling modes of fouling design |
| title | Permeate Flux in Ultrafiltration Processes—Understandings and Misunderstandings |
| title_full | Permeate Flux in Ultrafiltration Processes—Understandings and Misunderstandings |
| title_fullStr | Permeate Flux in Ultrafiltration Processes—Understandings and Misunderstandings |
| title_full_unstemmed | Permeate Flux in Ultrafiltration Processes—Understandings and Misunderstandings |
| title_short | Permeate Flux in Ultrafiltration Processes—Understandings and Misunderstandings |
| title_sort | permeate flux in ultrafiltration processes understandings and misunderstandings |
| topic | concentration polarization osmotic model fouling modes of fouling design |
| url | https://www.mdpi.com/2077-0375/12/2/187 |
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