Quantum molecular sieving separability of D-2 from an H-2-D-2 mixture was measured at 77 K for activated carbon fiber, carbon molecular sieve, zeolite and single wall carbon nanotube using a flow method. The amount of adsorbed D-2 was evidently larger than H-2 for all samples. The maximum adsorption ratio difference between D-2 and H-2 was 40% for zeolite (MS13X), yielding a selectivity for D-2 with respect to H2 of 3.05.