Isotopic separation of helium through graphyne membranes: a ring polymer molecular dynamics study. Issue 34 (13th August 2021)

• Record Type: Journal Article
• Authors: Bhowmick, Somnath; Hernández, Marta I.; Campos-Martínez, José; Suleimanov, Yury V.
• Is Part Of: Physical chemistry chemical physics. Volume 23:Issue 34(2021)
• Page Start: 18547
• Page End: 18557
• Publication Date: 2021-08-13
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d1cp02121d
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The rate of transmission of He isotopes through the nanopores of 2D graphdiyne and graphtriyne membranes has been investigated within cold to moderate temperature regime (10–250 K) by ring polymer molecular dynamics method. Abstract : Microscopic-level understanding of the separation mechanism for two-dimensional (2D) membranes is an active area of research due to potential implications of this class of membranes for various technological processes. Helium (He) purification from the natural resources is of particular interest due to the shortfall in its production. In this work, we applied the ring polymer molecular dynamics (RPMD) method to graphdiyne (Gr2) and graphtriyne (Gr3) 2D membranes having variable pore sizes for the separation of He isotopes, and compare for the first time with rigorous quantum calculations. We found that the transmission rate through Gr3 is many orders of magnitude greater than Gr2. The selectivity of either isotope at low temperatures is a consequence of a delicate balance between the zero-point energy effect and tunneling of 4 He and 3 He. In particular, a remarkable tunneling effect is reported on the Gr2 membrane at 10 K, leading to a much larger permeation of the lighter species as compared to the heavier isotope. RPMD provides an efficient approach for studying the separation of He isotopes, taking into account quantum effects of light nuclei motions at low temperatures, which classical methods fail to capture.