Surface Modification of TFC-PA RO Membrane by Grafting Hydrophilic pH Switchable Poly(Acrylic Acid) Brushes
The grafting of pH-responsive poly(acrylic acid) (PAA) brushes was carried out on the surface of a commercial TFC-PA membrane using surface-initiated atom transfer radical polymerization (SI-ATRP). Poly(t-butyl acrylate) was polymerized through the SI-ATRP method followed by its acid hydrolysis to f...
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| Format: | Article |
| Language: | English |
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Wiley
2020-01-01
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| Series: | Advances in Polymer Technology |
| Online Access: | http://dx.doi.org/10.1155/2020/8281058 |
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| author | Muhammad Asad Abbas Shehla Mushtaq Waqas A. Cheema Hazim Qiblawey Shenmin Zhu Yao Li Runnan Zhang Hong Wu Zhongyi Jiang Rehan Sadiq Nasir M. Ahmad |
| author_facet | Muhammad Asad Abbas Shehla Mushtaq Waqas A. Cheema Hazim Qiblawey Shenmin Zhu Yao Li Runnan Zhang Hong Wu Zhongyi Jiang Rehan Sadiq Nasir M. Ahmad |
| author_sort | Muhammad Asad Abbas |
| collection | DOAJ |
| description | The grafting of pH-responsive poly(acrylic acid) (PAA) brushes was carried out on the surface of a commercial TFC-PA membrane using surface-initiated atom transfer radical polymerization (SI-ATRP). Poly(t-butyl acrylate) was polymerized through the SI-ATRP method followed by its acid hydrolysis to form PAA hydrophilic polymer brushes. Surface morphology, permeation flux, salt rejection, and pore sizes were investigated. The contact angle for water was reduced from 50° for a pristine membrane to 27° for the modified membrane due to a modification with the hydrophilic functional group and its brush on membrane surfaces. The flux rate also increased noticeably at lower pH values relative to higher pH for the modified membranes, while the flux remains stable in the case of pristine TFC-PA membranes. There is slight transition in the water flux rate that was also observed when going from pH values of 3 to 5. This was attributed to the pH-responsive conformational changes for the grafted PAA brushes. At these pH values, ionization of the COOH group takes place below and above pKa to influence the effective pore dimension of the modified membranes. At a lower pH value, the PAA brushes seem to permit tight structure conformation resulting in larger pore sizes and hence more flux. On the other hand, at higher pH values, PAA brushes appeared to be in extended conformation to induce smaller pore sizes and result in less flux. Further, pH values were observed to not significantly affect the NaCl salt rejection with values observed in between 98.8% and 95% and close to that of the pristine TFC-PA membranes. These experimental results are significant and have immediate implication for advances in polymer technology to design and modify the “switchable membrane surfaces” with controllable charge distribution and surface wettability, as well as regulation of water flux and salt. |
| format | Article |
| id | doaj-art-0f52faa25efc489c8447f101dc93dca4 |
| institution | Kabale University |
| issn | 0730-6679 1098-2329 |
| language | English |
| publishDate | 2020-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in Polymer Technology |
| spelling | doaj-art-0f52faa25efc489c8447f101dc93dca42025-02-03T01:27:03ZengWileyAdvances in Polymer Technology0730-66791098-23292020-01-01202010.1155/2020/82810588281058Surface Modification of TFC-PA RO Membrane by Grafting Hydrophilic pH Switchable Poly(Acrylic Acid) BrushesMuhammad Asad Abbas0Shehla Mushtaq1Waqas A. Cheema2Hazim Qiblawey3Shenmin Zhu4Yao Li5Runnan Zhang6Hong Wu7Zhongyi Jiang8Rehan Sadiq9Nasir M. Ahmad10Polymer Research Lab, School of Chemical and Materials Engineering (SCME), National University of Sciences and Technology (NUST), H-12 Sector, Islamabad 44000, PakistanPolymer Research Lab, School of Chemical and Materials Engineering (SCME), National University of Sciences and Technology (NUST), H-12 Sector, Islamabad 44000, PakistanPolymer Research Lab, School of Chemical and Materials Engineering (SCME), National University of Sciences and Technology (NUST), H-12 Sector, Islamabad 44000, PakistanDepartment of Chemical Engineering, College of Engineering, Qatar University, P.O. Box 2713, Doha, QatarState Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, ChinaState Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, ChinaKey Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, ChinaKey Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, ChinaKey Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, ChinaSchool of Engineering, Faculty of Applied Science, Okanagan Campus, EME4242-1137 Alumni Ave., Kelowna, BC, V1V 1V7, CanadaPolymer Research Lab, School of Chemical and Materials Engineering (SCME), National University of Sciences and Technology (NUST), H-12 Sector, Islamabad 44000, PakistanThe grafting of pH-responsive poly(acrylic acid) (PAA) brushes was carried out on the surface of a commercial TFC-PA membrane using surface-initiated atom transfer radical polymerization (SI-ATRP). Poly(t-butyl acrylate) was polymerized through the SI-ATRP method followed by its acid hydrolysis to form PAA hydrophilic polymer brushes. Surface morphology, permeation flux, salt rejection, and pore sizes were investigated. The contact angle for water was reduced from 50° for a pristine membrane to 27° for the modified membrane due to a modification with the hydrophilic functional group and its brush on membrane surfaces. The flux rate also increased noticeably at lower pH values relative to higher pH for the modified membranes, while the flux remains stable in the case of pristine TFC-PA membranes. There is slight transition in the water flux rate that was also observed when going from pH values of 3 to 5. This was attributed to the pH-responsive conformational changes for the grafted PAA brushes. At these pH values, ionization of the COOH group takes place below and above pKa to influence the effective pore dimension of the modified membranes. At a lower pH value, the PAA brushes seem to permit tight structure conformation resulting in larger pore sizes and hence more flux. On the other hand, at higher pH values, PAA brushes appeared to be in extended conformation to induce smaller pore sizes and result in less flux. Further, pH values were observed to not significantly affect the NaCl salt rejection with values observed in between 98.8% and 95% and close to that of the pristine TFC-PA membranes. These experimental results are significant and have immediate implication for advances in polymer technology to design and modify the “switchable membrane surfaces” with controllable charge distribution and surface wettability, as well as regulation of water flux and salt.http://dx.doi.org/10.1155/2020/8281058 |
| spellingShingle | Muhammad Asad Abbas Shehla Mushtaq Waqas A. Cheema Hazim Qiblawey Shenmin Zhu Yao Li Runnan Zhang Hong Wu Zhongyi Jiang Rehan Sadiq Nasir M. Ahmad Surface Modification of TFC-PA RO Membrane by Grafting Hydrophilic pH Switchable Poly(Acrylic Acid) Brushes Advances in Polymer Technology |
| title | Surface Modification of TFC-PA RO Membrane by Grafting Hydrophilic pH Switchable Poly(Acrylic Acid) Brushes |
| title_full | Surface Modification of TFC-PA RO Membrane by Grafting Hydrophilic pH Switchable Poly(Acrylic Acid) Brushes |
| title_fullStr | Surface Modification of TFC-PA RO Membrane by Grafting Hydrophilic pH Switchable Poly(Acrylic Acid) Brushes |
| title_full_unstemmed | Surface Modification of TFC-PA RO Membrane by Grafting Hydrophilic pH Switchable Poly(Acrylic Acid) Brushes |
| title_short | Surface Modification of TFC-PA RO Membrane by Grafting Hydrophilic pH Switchable Poly(Acrylic Acid) Brushes |
| title_sort | surface modification of tfc pa ro membrane by grafting hydrophilic ph switchable poly acrylic acid brushes |
| url | http://dx.doi.org/10.1155/2020/8281058 |
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