Process for separating and recovering hydrogen isotope

Hydrogen isotope is separated and recovered with remarkable reduction in energy consumption in a compact apparatus using a cold reactor and a hot reactor based on dual temperature process by a combination of a first step of at least one isotope exchange reaction stage comprising contacting mists of a feed liquid cocurrently together with a reacting gas with an isotope exchange reaction catalyst at a low temperature, and a second step of a plurality of stages each comprising a gas-liquid contact of the liquid from the first step with vapor of the liquid and the reacting gas and an isotope exchange reaction between the vapor of the liquid and the reacting gas at a high temperature