Selective Nanopores in Graphene Sheet for Separation I-129 Isotope from Air

Abstract

Molecular dynamic simulation was used to investigate the ability of nanoporous graphene membrane in gas separation process. Three di-atomic gases (I2, N2 and O2) were considered, in which different pore sizes were modeled on graphene. The structure contains an impermeable movable wall (piston) to push the mixture gases toward the nanoporous graphene membrane. Two different simulations were carried out, with two different piston velocities. Two key factors in gases separation process are the pore size of graphene and the velocity of movable wall. The results revealed that I-129 separation was improved by using proper size of pore and by decreasing the velocity of movable wall. It was also found that the I-129 gas radionuclides could be completely separated from nitrogen and oxygen molecules in the pore-12 graphene configuration. It was also found that nitrogen was more strongly adsorbed onto the membrane than oxygen, while I-129 was not adsorbed.