Design, development and evaluation of nanofibrous composite membranes with opposing membrane wetting properties for extractive membrane bioreactors
Extractive membrane bioreactors (EMBRs) are promising wastewater treatment processes combining an aqueous-aqueous extractive membrane process and biodegradation. The target contaminants diffuse through an extractive membrane and are metabolized by the active biofilm attached on the downstream membra...
| Main Authors: | , , , , |
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| Format: | Journal Article |
| Language: | English |
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2020
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| Online Access: | https://hdl.handle.net/10356/136797 |
| _version_ | 1811679782923927552 |
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| author | Liao, Yuan Goh, Shuwen Tian, Miao Wang, Rong Fane, Anthony G. |
| author2 | School of Civil and Environmental Engineering |
| author_facet | School of Civil and Environmental Engineering Liao, Yuan Goh, Shuwen Tian, Miao Wang, Rong Fane, Anthony G. |
| author_sort | Liao, Yuan |
| collection | NTU |
| description | Extractive membrane bioreactors (EMBRs) are promising wastewater treatment processes combining an aqueous-aqueous extractive membrane process and biodegradation. The target contaminants diffuse through an extractive membrane and are metabolized by the active biofilm attached on the downstream membrane surface and microorganisms in the bioreactor. The benefit of EMBRs is that the biomass is not exposed to the potentially hostile feed conditions (high salinity, pH extremes etc.). The physicochemical properties of membrane surfaces on the receiving side facing the bioreactor are critical in controlling the extent and nature of the membrane-attached biofilm. In this work, novel nanofibrous composite membranes with a superhydrophobic surface (coded as NC) or a superhydrophilic surface (coded as M-NC) on the receiving side have been designed, developed and evaluated in EMBRs. Compared to commercial polydimethysiloxane (PDMS) tubular membranes, both NC and M-NC possessed 10 times higher phenol extraction efficiency in an aqueous-aqueous extractive membrane process. The uncontrolled biofilm growth on the membrane surface after 12 days of cross flow EMBR (CF-EMBR) operation resulted in 62% reductions of overall mass transfer coefficients (k0) of both NC and M-NC. However, both membranes exhibited better performance in a submerged EMBR (S-EMBR) configuration due to the presence of air bubbles scouring on the membrane surface. Moreover, the fouling-releasing fluoro-polymeric surface of the hydrophobic NC was able to attenuate the tendency of microbial attachment and encourage biofilm scouring from the membrane surface in the S-EMBR. In contrast, more polysaccharides were present in the biofilm on the poly (ethylene glycol) (PEG)-modified M-NC surface, which acted as adhesives to tightly immobilize the biofilm on the membrane surface. Lastly, the NC which exhibited a higher stable k0 of 5.7 × 10−7 m/s in 12 days of S-EMBR operation, has been tested in a pilot S-EMBR to treat actual industrial wastewater. It showed a stable and competitive k0 of 6.5 × 10−7 m/s in 31 days operation, demonstrating its feasibility for hostile industrial wastewater treatment. |
| first_indexed | 2024-10-01T03:14:38Z |
| format | Journal Article |
| id | ntu-10356/136797 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T03:14:38Z |
| publishDate | 2020 |
| record_format | dspace |
| spelling | ntu-10356/1367972020-01-29T05:12:47Z Design, development and evaluation of nanofibrous composite membranes with opposing membrane wetting properties for extractive membrane bioreactors Liao, Yuan Goh, Shuwen Tian, Miao Wang, Rong Fane, Anthony G. School of Civil and Environmental Engineering Nanyang Environment and Water Research Institute Singapore Membrane Technology Centre Engineering::Civil engineering Superhydrophobic Superhydrophilic Extractive membrane bioreactors (EMBRs) are promising wastewater treatment processes combining an aqueous-aqueous extractive membrane process and biodegradation. The target contaminants diffuse through an extractive membrane and are metabolized by the active biofilm attached on the downstream membrane surface and microorganisms in the bioreactor. The benefit of EMBRs is that the biomass is not exposed to the potentially hostile feed conditions (high salinity, pH extremes etc.). The physicochemical properties of membrane surfaces on the receiving side facing the bioreactor are critical in controlling the extent and nature of the membrane-attached biofilm. In this work, novel nanofibrous composite membranes with a superhydrophobic surface (coded as NC) or a superhydrophilic surface (coded as M-NC) on the receiving side have been designed, developed and evaluated in EMBRs. Compared to commercial polydimethysiloxane (PDMS) tubular membranes, both NC and M-NC possessed 10 times higher phenol extraction efficiency in an aqueous-aqueous extractive membrane process. The uncontrolled biofilm growth on the membrane surface after 12 days of cross flow EMBR (CF-EMBR) operation resulted in 62% reductions of overall mass transfer coefficients (k0) of both NC and M-NC. However, both membranes exhibited better performance in a submerged EMBR (S-EMBR) configuration due to the presence of air bubbles scouring on the membrane surface. Moreover, the fouling-releasing fluoro-polymeric surface of the hydrophobic NC was able to attenuate the tendency of microbial attachment and encourage biofilm scouring from the membrane surface in the S-EMBR. In contrast, more polysaccharides were present in the biofilm on the poly (ethylene glycol) (PEG)-modified M-NC surface, which acted as adhesives to tightly immobilize the biofilm on the membrane surface. Lastly, the NC which exhibited a higher stable k0 of 5.7 × 10−7 m/s in 12 days of S-EMBR operation, has been tested in a pilot S-EMBR to treat actual industrial wastewater. It showed a stable and competitive k0 of 6.5 × 10−7 m/s in 31 days operation, demonstrating its feasibility for hostile industrial wastewater treatment. EDB (Economic Devt. Board, S’pore) Accepted version 2020-01-29T05:12:46Z 2020-01-29T05:12:46Z 2018 Journal Article Liao, Y., Goh, S., Tian, M., Wang, R., & Fane, A. G. (2018). Design, development and evaluation of nanofibrous composite membranes with opposing membrane wetting properties for extractive membrane bioreactors. Journal of Membrane Science, 551, 55-65. doi:10.1016/j.memsci.2018.01.029 0376-7388 https://hdl.handle.net/10356/136797 10.1016/j.memsci.2018.01.029 2-s2.0-85041469531 551 55 65 en Journal of Membrane Science © 2018 Elsevier B.V. All rights reserved. This paper was published in Journal of Membrane Science and is made available with permission of Elsevier B.V. application/pdf |
| spellingShingle | Engineering::Civil engineering Superhydrophobic Superhydrophilic Liao, Yuan Goh, Shuwen Tian, Miao Wang, Rong Fane, Anthony G. Design, development and evaluation of nanofibrous composite membranes with opposing membrane wetting properties for extractive membrane bioreactors |
| title | Design, development and evaluation of nanofibrous composite membranes with opposing membrane wetting properties for extractive membrane bioreactors |
| title_full | Design, development and evaluation of nanofibrous composite membranes with opposing membrane wetting properties for extractive membrane bioreactors |
| title_fullStr | Design, development and evaluation of nanofibrous composite membranes with opposing membrane wetting properties for extractive membrane bioreactors |
| title_full_unstemmed | Design, development and evaluation of nanofibrous composite membranes with opposing membrane wetting properties for extractive membrane bioreactors |
| title_short | Design, development and evaluation of nanofibrous composite membranes with opposing membrane wetting properties for extractive membrane bioreactors |
| title_sort | design development and evaluation of nanofibrous composite membranes with opposing membrane wetting properties for extractive membrane bioreactors |
| topic | Engineering::Civil engineering Superhydrophobic Superhydrophilic |
| url | https://hdl.handle.net/10356/136797 |
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