Process for exchanging hydrogen isotopes between gaseous hydrogen and water

It is an object of this invention to provide an efficient method for the exchange of isotopes of hydrogen, particularly tritium, between water and hydrogen gas, and to provide a method for the separation and concentration of said isotopes in liquid water. These objects are accomplished by a method which comprises the steps of: (a) (i) introducing hydrogen gas depleted in tritium, and water in the vapor phase, said water containing tritium, into a first reaction zone, contacting in said zone in co-current flow at a temperature in the range of from about 225 deg.C to about 300 deg.C said water vapor and hydrogen gas with a supported metal catalyst, withdrawing from said zone an effluent stream comprising a mixture of hydrogen gas enriched in tritium and water vapor depleted in tritium, and condensing said water vapor to liquid water; or (a) (ii) introducing hydrogen gas depleted in tritium, and liquid phase water, said water containing tritium, into a first reaction zone, contacting in said zone in counter-current flow at a temperature of about 100 deg.C said liquid phase water and hydrogen gas with a hydrophobic catalyst comprising a coherent film of a hydrophobic polymer, said film being disposed on a low surface area support and containing at least one finely divided catalytically Group active VIII metal on a high surface area carrier and withdrawing from said first reaction zone a stream of hydrogen gas enriched in tritium and liquid water depleted in tritium; and (b) introducing said hydrogen gas enriched in tritium into a second reaction zone, contacting in counter-current flow at a temperature in the range from about 0 deg.C to about 50 deg.C said liquid water and said hydrogen gas enriched in tritium with a hydrophobic catalyst, and withdrawing from said second reaction zone a liquid water effluent stream enriched in tritium and a hydrogen gas depleted in tritium. The hydrogen gas depleted in tritium from step (b) is normally used as the hydrogen gas in step (a) (i) or (a) (ii) to operate the method continuously