Improved hydrogen isotope separation via Cu-exchanged Gismondine-type zeolites

Abstract

The growing demand for pure deuterium (D₂) and the need to manage nuclear wastewater have driven research into more efficient hydrogen isotope separation technologies. Quantum sieving techniques, such as Kinetic Quantum Sieving (KQS) and Chemical-Affinity Quantum Sieving (CAQS), have been proposed as alternatives to conventional, energy-intensive methods. However, commercially viable technologies remain undeveloped. In this study, we synthesized Na-GIS-type zeolites (NG zeolites) and Cu-exchanged Na-GIS-type zeolites (CNG zeolites) with a flexible framework and narrow pore size to explore the potential of structural variations for hydrogen isotope separation. The Cu-ion exchange significantly improved the desorption temperature and overall performance, especially for D₂ uptake. At 25 K, 100 mbar, and 10 min, CNG zeolite showed a separation factor of 11.56 (2.23 mmol/g), outperforming NG zeolite with a separation factor of 4.74 (1.13 mmol/g). Furthermore, NG zeolite exhibited a synthesis cost of £57,075 per gram and a space–time yield of 9.72 × 10⁻² g/(day·m³), demonstrating its potential for commercial application. This research highlights the promise of using zeolite structural variations for scalable and economically viable hydrogen isotope separation.