Probing the Contributions of Interior and Exterior Channels of Nanofillers toward the Enhanced Separation Performance of a Thin-Film Nanocomposite Reverse Osmosis Membrane

• Published in: Environmental science & technology letters Vol. 7; no. 10; pp. 766 - 772
• Main Authors: Yin, Jun, Yang, Zhe, Tang, Chuyang Y, Deng, Baolin
• Format: Journal Article
• Language: English
• Published: American Chemical Society 13.10.2020
• Subjects: desalination; hydrophilicity; hydrophobicity; nanocomposites; reverse osmosis; seawater; Treatment and Resource Recovery; water reuse
• ISSN: 2328-8930; 2328-8930
• DOI: 10.1021/acs.estlett.0c00507

Thin-film nanocomposite (TFN) membranes have been increasingly used in seawater desalination and wastewater reclamation. Despite their potential to overcome the long-standing permeability–selectivity trade-off, the underlying mechanisms for the transport of water through TFN membranes are not fully understood. In this study, we conducted an in-depth analysis of the transport of water through the TFN membranes containing nanoparticles with systematically changed properties (hydrophilic vs hydrophobic and porous vs nonporous). For the first time, we were able to resolve the respective contributions to the enhanced membrane performance by the exterior and interior channels of the nanofillers based on direct experimental evidence. Incorporating solid hydrophobic nanofillers showed little enhancement of water flux. In contrast, exterior channels created by hydrophilic nanofillers and interior channels of porous nanofillers had water flux enhancements of 26.9% and 18.3%, respectively, under similar particle loading conditions. Furthermore, the combined effects of both exterior and interior channels resulted in a 51.9% flux enhancement. Our work provides mechanistic insights into the formation and transport mechanisms involved in TFN membranes, which lay a solid foundation for optimizing these membranes for desalination and water reuse.