Assessing the Limits of He Isotope Separation Under
Abstract
Separation of helium isotopes is of interest owing to the critical importance and limited supply of helium-3 (3He). Nanoporous materials offer a viable route for gas-phase isotope separation through either selective adsorption or quantum sieving. Here, to maximize the isotope selectivity of quantum sieving we propose coupling a strongly attracting open-metal site for He adsorption to a surrounding nanopore acting as a confining potential. We demonstrate that upon tightening the pore, the zero-point energy (ZPE) elevates up to a point where 3He detaches while 4He remains bound. Our model shows that 100% isotope-selective adsorption of 4He is achieved when pores of diameter 4.8-5.3 Å are coupled to metal sites with He binding energies of 2-20 kJ/mol. At 20 K, operating pressures between 0.3-30 bar are estimated, which increase to 2-6 kbar at 77 K. Even if the exact pore size for 100% isotope-selective adsorption cannot be realized, our results provide a rational design strategy for materials with unprecedentedly large He isotope separation factors at elevated temperatures.
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BibTeX
@misc{dongmo2026assessing,
title = {{Assessing the Limits of He Isotope Separation Under}},
author = {Elvira Gouatieu Dongmo and Felix Moncada and Shubhajit Das and Toshiki Riemer-Wulf and Thomas Heine},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010286/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010286/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Assessing the Limits of He Isotope Separation Under
AU - Elvira Gouatieu Dongmo
AU - Felix Moncada
AU - Shubhajit Das
AU - Toshiki Riemer-Wulf
AU - Thomas Heine
PY - 2026
DA - 2026/10/12
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010286/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010286/v1
AB - Separation of helium isotopes is of interest owing to the critical importance and limited supply of helium-3 (3He). Nanoporous materials offer a viable route for gas-phase isotope separation through either selective adsorption or quantum sieving. Here, to maximize the isotope selectivity of quantum sieving we propose coupling a strongly attracting open-metal site for He adsorption to a surrounding nanopore acting as a confining potential. We demonstrate that upon tightening the pore, the zero-point energy (ZPE) elevates up to a point where 3He detaches while 4He remains bound. Our model shows that 100% isotope-selective adsorption of 4He is achieved when pores of diameter 4.8-5.3 Å are coupled to metal sites with He binding energies of 2-20 kJ/mol. At 20 K, operating pressures between 0.3-30 bar are estimated, which increase to 2-6 kbar at 77 K. Even if the exact pore size for 100% isotope-selective adsorption cannot be realized, our results provide a rational design strategy for materials with unprecedentedly large He isotope separation factors at elevated temperatures.
ER -