Effect of pore size distribution on the desalination performance of the selective layer of nanoporous atomically-thin membranes
Name
Chow_et_al_Manuscript_Rev1.pdf
Description
Accepted version
Size
3.82 MB
Format
Adobe PDF
Checksum (MD5)
17e77318442036fe311bf77bc8dd1d88
Author(s)
Chow, Chun-Man
Karnik, Rohit
Date Issued
September 2023
Journal
Desalination
Publisher
Elsevier BV
Citation
Chow, Chun-Man and Karnik, Rohit. 2023. "Effect of pore size distribution on the desalination performance of the selective layer of nanoporous atomically-thin membranes." Desalination, 561.
Version
Author's final manuscript
Abstract
Over the last decade, molecular simulations and experiments have shown that nanoporous atomically-thin membranes (NATMs) have the potential for high-permeance, high-selectivity separations, including seawater desalination. Realistic NATMs contain polydisperse pore sizes that could impede their performance, as large pores lead to salt leakage. This paper computationally examines the effect of pore size distributions (PSDs) on the desalination performance of the selective layer of NATMs by reverse osmosis (RO), considering size exclusion as the dominant selection mechanism. Analogous to thin-film composite RO membranes, the finite width of PSDs leads to a trade-off between water permeability and water/salt selectivity in NATMs. Tight PSDs with average pore sizes slightly below the size of the salt are needed to ensure high selectivity comparable to TFC membranes with high water permeance. Sealing of large, salt-permeable pores (e.g. by interfacial polymerization) limits salt leakage but substantially reduces water permeance. Introducing energy barriers that impede salt permeation by tuning nanopore structure and chemistry can make NATMs more robust to wider PSDs. In summary, some combination of control of PSDs, leakage mitigation, and pore functionalization is essential for NATMs to surpass the permeability/selectivity trade-off of polymeric RO membranes and achieve high water permeance with good salt rejection.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
Creative Commons Attribution-Noncommercial-ShareAlike
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1016/j.desal.2023.116645
