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Molecular insights into the structure-property relationships of 3D printed polyamide reverse-osmosis membrane for desalination

He, Jinlong and Yang, Jason and McCutcheon, Jeffrey R. and Li, Ying (2022) Molecular insights into the structure-property relationships of 3D printed polyamide reverse-osmosis membrane for desalination. Journal of Membrane Science, 658 . Art. No. 120731. ISSN 0376-7388. doi:10.1016/j.memsci.2022.120731.

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3D-printing is an emerging method for manufacturing polyamide (PA) reserve osmosis (RO) membranes for water treatment and desalination, which can precisely control membrane structural properties, such as thickness, roughness, and resolution. However, the synthesis-structure (i.e., degree of cross-linking (DC), m-phenylenediamine/trimesoyl chloride (MPD/TMC) ratio, and membrane thickness) to property (permeability and water-salt selectivity) relationships for these membranes has not been well understood. At the same time, a microscopic understanding of the physical mechanism of water and salt transport is needed to guide the design of high-performance 3D-printed membranes and improve the printing efficiency. Thus, the atomic-scale transport features and energetics of water and salt ions are studied at high pressure for the 3D-printed PA RO membranes with the different DCs and MPD/TMC ratios through non-equilibrium molecular dynamics (NEMD) simulations. Factoring in membrane structure properties, rejection ratio of salt ions and pressure-dependent water flux, 3D-printed PA membranes having an MPD/TMC ratio of 3.0:2.0 and a DC between 80%∼90% attains ideal performance: high water flux, high rejection of salt ions, and excellent structural integrity. Mechanistically, water permeability for highly cross-linked PA RO membranes depends on the temporary on-and-off channels that allow water molecules to jump from one cavity to another at high pressure. In addition, higher pressures cause rapid compaction of PA membranes’ free volume and membrane thickness. Membrane failure at high pressure is determined by the DC and MPD/TMC ratios-dependent compressive yield strength. In short, these findings provide physical insights for optimizing existing PA membranes and designing next-generation desalination membranes at the molecular level.

Item Type:Article
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URLURL TypeDescription Information
Yang, Jason0000-0003-3184-1550
Li, Ying0000-0002-1487-3350
Additional Information:© 2022 Elsevier. Received 21 March 2022, Revised 27 May 2022, Accepted 9 June 2022, Available online 18 June 2022, Version of Record 21 June 2022. Y.L. and J.R.M would like to thank the support from the National Alliance for Water Innovation (NAWI), funded by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy (EERE), Advanced Manufacturing Office, under Funding Opportunity Announcement Number DE-FOA-0001905. J.Y. would like to express thanks for the support by the U.S. National Science Foundation Graduate Research Fellowship Program under Grant No. 2021309491. Y.L. also gratefully acknowledges financial support from the U.S. National Science Foundation (CMMI-1762661, CMMI-1934829 and CAREER Award CMMI-2046751) and 3 M's Non-Tenured Faculty Award. Any opinion, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the U.S. National Science Foundation and Department of Energy. This research also benefited in part from the computational resources and staff contributions provided by the Booth Engineering Center for Advanced Technology (BECAT) at the University of Connecticut. The authors also acknowledge the Texas Advanced Computing Center (TACC) at The University of Texas at Austin (Frontera project and National Science Foundation Award 1818253) and National Renewable Energy Laboratory (Eagle Computing System) for providing HPC resources that have contributed to the research results reported within this paper. Author statement. Jinlong He: Conceptualization, Methodology, Software, Validation, Formal analysis, Data curation, Writing – original draft, Visualization. Jason Yang: Conceptualization, Methodology, Software, Writing – review & editing. Jeffrey R McCutcheon: Conceptualization, Methodology, Supervision, Project administration, Funding acquisition. Ying Li: Conceptualization, Methodology, Software, Writing – review & editing, Supervision, Project administration, Funding acquisition. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Funding AgencyGrant Number
Department of Energy (DOE)DE-FOA-0001905
NSF Graduate Research Fellowship2021309491
Subject Keywords:3D-printed PA RO membrane; Water desalination; Pore size distribution; Cross-linking degree; Compressive yield strength; Non-equilibrium molecular dynamics
Record Number:CaltechAUTHORS:20220705-346573000
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Official Citation:Jinlong He, Jason Yang, Jeffrey R. McCutcheon, Ying Li, Molecular insights into the structure-property relationships of 3D printed polyamide reverse-osmosis membrane for desalination, Journal of Membrane Science, Volume 658, 2022, 120731, ISSN 0376-7388,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:115330
Deposited By: George Porter
Deposited On:08 Jul 2022 23:00
Last Modified:25 Jul 2022 23:14

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