Mitigation of bidirectional solute flux in forward osmosis via membrane surface coating of zwitterion functionalized carbon nanotubes
| dc.contributor.author | Zou, Shiqiang | en |
| dc.contributor.author | Smith, Ethan D. | en |
| dc.contributor.author | Lin, Shihong | en |
| dc.contributor.author | Martin, Stephen M. | en |
| dc.contributor.author | He, Zhen | en |
| dc.contributor.department | Civil and Environmental Engineering | en |
| dc.contributor.department | Chemical Engineering | en |
| dc.contributor.department | Macromolecules Innovation Institute | en |
| dc.date.accessioned | 2019-12-16T13:58:25Z | en |
| dc.date.available | 2019-12-16T13:58:25Z | en |
| dc.date.issued | 2019-07-08 | en |
| dc.description.abstract | Forward osmosis (FO) has emerged as a promising membrane technology to yield high-quality reusable water from various water sources. A key challenge to be solved is the bidirectional solute flux (BSF), including reverse solute flux (RSF) and forward solute flux (FSF). Herein, zwitterion functionalized carbon nanotubes (Z-CNTs) have been coated onto a commercial thin film composite (TFC) membrane, resulting in BSF mitigation via both electrostatic repulsion forces induced by zwitterionic functional groups and steric interactions with CNTs. At a coating density of 0.97 gm⁻², a significantly reduced specific RSF was observed for multiple draw solutes, including NaCl (55.5% reduction), NH₄H₂PO₄(83.8%), (NH₄)₂HPO₄ (74.5%), NH₄Cl (70.8%), and NH₄HCO₃ (61.9%). When a synthetic wastewater was applied as the feed to investigate membrane rejection, FSF was notably reduced by using the coated membrane with fewer pollutants leaked to the draw solution, including NH₄⁺-N (46.3% reduction), NO₂⁻₋N (37.0%), NO₂⁻₋N (30.3%), K⁺ (56.1%), PO₄³⁻₋P (100%), and Mg²⁺ (100%). When fed with real wastewater, a consistent water flux was achieved during semi-continuous operation with enhanced fouling resistance. This study is among the earliest efforts to address BSF control via membrane modification, and the results will encourage further exploration of effective strategies to reduce BSF. | en |
| dc.description.sponsorship | This research was financially supported by Institute for Critical Technology and Applied Science, Virginia Tech. Shiqiang Zou was partially supported by a Fellowship from Water INTERface IGEP at Virginia Tech. We sincerely thank Mr. Li Wang (Vanderbilt University) for his help with the analysis of membrane zeta potential and Virginia Tech Open Access Subvention Fund for covering publication expense. | en |
| dc.format.mimetype | application/pdf | en |
| dc.identifier.doi | https://doi.org/10.1016/j.envint.2019.104970 | en |
| dc.identifier.uri | http://hdl.handle.net/10919/95997 | en |
| dc.identifier.volume | 131 | en |
| dc.language.iso | en | en |
| dc.publisher | Elsevier | en |
| dc.rights | Creative Commons Attribution-NonCommercial-NoDerivs 3.0 United States | en |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/3.0/us/ | en |
| dc.subject | Forward osmosis | en |
| dc.subject | Reverse solute flux | en |
| dc.subject | Forward solute flux | en |
| dc.subject | Zwitterion | en |
| dc.subject | Membrane modification | en |
| dc.title | Mitigation of bidirectional solute flux in forward osmosis via membrane surface coating of zwitterion functionalized carbon nanotubes | en |
| dc.title.serial | Environment International | en |
| dc.type | Article | en |
| dc.type.dcmitype | Text | en |