Nanoporous Graphene Membranes for Efficient 3He/4He Separation

Nanoporous functionalized graphene membranes containing nitrogen atoms in a nanosized ring pore have the capability to separate He-3 from He-4 efficiently by quantum tunneling through the pore. Calculations on size-reduced model systems of single-graphene pores reveal that a balanced choice of tunneling barrier height and low gas temperature boosts the selectivity and keeps the helium gas flux at an industrially exploitable level.