I&EC Mary Moore  Wednesday, August 22, 2012 

123 - Isotope separation using quantum tunneling

Joshua Schrier, jschrier@haverford.edu, Department of Chemistry, Haverford College, Haverford, PA 19041, United States

Quantum mechanical tunneling is widely used in electronics, but is unexplored for performing chemical separations. Recent theoretical work has revealed that quantum tunneling makes a substantial contribution to the transmission of helium atoms through nanoporous graphene sheets, even at room temperature. The mass-dependence of quantum tunneling provides a new means for performing membrane-based gas separations of isotopes at much lower capital and energy cost than traditional cryogenic distillation and gas centrifuge methods. I will discuss the theory of quantum tunneling-based membrane separation and recent work on the design of improved nanoporous structures yielding 3He/4He selectivities of up to 19, with nanomole cm-2 s-1 flux rates. I will also discuss the design of bilayer-nanostructures exhibiting resonant tunneling transmission. Unlike classical membranes where permeance is inversely proportional to membrane thickness, the resonant tunneling states of the bilayer increases the flux rate by an order of magnitude compared to a single-layer structure, while also increasing the isotope selectivity.


Wednesday, August 22, 2012 02:00 PM
General Papers (01:00 PM - 02:40 PM)
Location: Pennsylvania Convention Center
Room: 109 A

 

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