Production of molecular deuterium-tritium (D-T) with very low molecular tritium (T2) is necessary for application as a nuclear spin polarized fuel. Selective adsorption of hydrogen isotopes on zeolites or alumina can provide the separation needed to produce D-T with very low T2. Use of an adsorption column at 20–25 K offers low inventory, compact size, and rapid operation, in comparison with conventional separation techniques such as cryogenic distillation or thermal diffusion. We discuss principles of adsorption, and describe a calculational model of the adsorption column and operational implications revealed by it. We show experimental proof-of-principle data for removal of T2 from D-T with an adsorption column operated at 23 K.