Mixed polyamide-based composite nanofiltration hollow fiber membranes with improved low-pressure water softening capability
Mixed polyamide-based composite nanofiltration (NF) hollow fiber membranes with suitable characteristics for water softening under ultrafiltration (UF)-range low operating pressure were successfully developed. The thin-film selective layer of the composite membrane was formed via interfacial polymer...
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sg-ntu-dr.10356-1058962020-09-26T22:03:33Z Mixed polyamide-based composite nanofiltration hollow fiber membranes with improved low-pressure water softening capability Fang, Wangxi Shi, Lei Wang, Rong School of Civil and Environmental Engineering Siemens Global R&D Centre (Water Technologies) Nanyang Environment and Water Research Institute Singapore Membrane Technology Centre DRNTU::Engineering::Environmental engineering::Water treatment Mixed polyamide-based composite nanofiltration (NF) hollow fiber membranes with suitable characteristics for water softening under ultrafiltration (UF)-range low operating pressure were successfully developed. The thin-film selective layer of the composite membrane was formed via interfacial polymerization on the inner surface of a microporous polyethersulfone (PES) hollow fiber substrate with trymesoyl chloride (TMC) being the organic phase monomer, and a mixture of branched polyethyleneimine (PEI) and piperazine (PIP) being the monomers in the aqueous phase. In was found that there was a synergetic effect of PEI and PIP on the formation of the selective layer. The water permeability and salt rejection of the resultant membrane were both enhanced with a small amount of PIP added into the PEI aqueous phase, but dropped quickly with a higher PIP to PEI ratio. The optimized NF membrane possessed a molecular weight cut-off (MWCO) of 380 Da, an effective pore diameter of 1.27 nm, and pure water permeability (PWP) of 18.2 l/m2 h bar. Under an operating pressure of 2 bar, the membrane exhibited rejection of 96.3% and 93.8% to 1000 ppm MgCl2 and MgSO4 feed solutions, respectively. The capability of the newly developed membrane for low-pressure water softening was evaluated by employing simulated hard water feed solutions with different ionic compositions and total hardness. By the combining effect of electrostatic repulsion and size exclusion, the mixed PEI/PIP-based composite hollow fiber offered superior water softening performance compared with the membranes made with PEI or PIP alone as the aqueous phase IP monomer. NRF (Natl Research Foundation, S’pore) EDB (Economic Devt. Board, S’pore) Accepted version 2014-09-22T08:10:59Z 2019-12-06T22:00:18Z 2014-09-22T08:10:59Z 2019-12-06T22:00:18Z 2014 2014 Journal Article ang, W., Shi, L., & Wang, R. (2014). Mixed polyamide-based composite nanofiltration hollow fiber membranes with improved low-pressure water softening capability. Journal of membrane science, 468, 52-61. 0376-7388 https://hdl.handle.net/10356/105896 http://hdl.handle.net/10220/20948 10.1016/j.memsci.2014.05.047 en Journal of membrane science © 2014 Elsevier B. V. This is the author created version of a work that has been peer reviewed and accepted for publication by Journal of Membrane Science. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1016/j.memsci.2014.05.047]. 25 p. + 15 p. figures application/pdf application/pdf |
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DRNTU::Engineering::Environmental engineering::Water treatment Fang, Wangxi Shi, Lei Wang, Rong Mixed polyamide-based composite nanofiltration hollow fiber membranes with improved low-pressure water softening capability |
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Mixed polyamide-based composite nanofiltration (NF) hollow fiber membranes with suitable characteristics for water softening under ultrafiltration (UF)-range low operating pressure were successfully developed. The thin-film selective layer of the composite membrane was formed via interfacial polymerization on the inner surface of a microporous polyethersulfone (PES) hollow fiber substrate with trymesoyl chloride (TMC) being the organic phase monomer, and a mixture of branched polyethyleneimine (PEI) and piperazine (PIP) being the monomers in the aqueous phase. In was found that there was a synergetic effect of PEI and PIP on the formation of the selective layer. The water permeability and salt rejection of the resultant membrane were both enhanced with a small amount of PIP added into the PEI aqueous phase, but dropped quickly with a higher PIP to PEI ratio. The optimized NF membrane possessed a molecular weight cut-off (MWCO) of 380 Da, an effective pore diameter of 1.27 nm, and pure water permeability (PWP) of 18.2 l/m2 h bar. Under an operating pressure of 2 bar, the membrane exhibited rejection of 96.3% and 93.8% to 1000 ppm MgCl2 and MgSO4 feed solutions, respectively. The capability of the newly developed membrane for low-pressure water softening was evaluated by employing simulated hard water feed solutions with different ionic compositions and total hardness. By the combining effect of electrostatic repulsion and size exclusion, the mixed PEI/PIP-based composite hollow fiber offered superior water softening performance compared with the membranes made with PEI or PIP alone as the aqueous phase IP monomer. |
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School of Civil and Environmental Engineering |
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School of Civil and Environmental Engineering Fang, Wangxi Shi, Lei Wang, Rong |
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Article |
author |
Fang, Wangxi Shi, Lei Wang, Rong |
author_sort |
Fang, Wangxi |
title |
Mixed polyamide-based composite nanofiltration hollow fiber membranes with improved low-pressure water softening capability |
title_short |
Mixed polyamide-based composite nanofiltration hollow fiber membranes with improved low-pressure water softening capability |
title_full |
Mixed polyamide-based composite nanofiltration hollow fiber membranes with improved low-pressure water softening capability |
title_fullStr |
Mixed polyamide-based composite nanofiltration hollow fiber membranes with improved low-pressure water softening capability |
title_full_unstemmed |
Mixed polyamide-based composite nanofiltration hollow fiber membranes with improved low-pressure water softening capability |
title_sort |
mixed polyamide-based composite nanofiltration hollow fiber membranes with improved low-pressure water softening capability |
publishDate |
2014 |
url |
https://hdl.handle.net/10356/105896 http://hdl.handle.net/10220/20948 |
_version_ |
1681059618394996736 |