Separating hydrogen isotopic water close to actual conditions by graphene oxide (GO) membrane-based vapour permeation

The treatment of waste tritiated water (HTO) in the nuclear energy field involves the separation of H 2 O/HTO, and the vapour release process with high temperature heating is one of the proposed solutions. Such process is energy-intensive, membrane-based processes have been studied as the alternative. The efficient separation of light water/deuteriated water (H 2 O/D 2 O), which is often used as a model process for H 2 O/HTO separation, has been recently reported through membrane processes with novel membrane materials or structures, nevertheless, the effect of water feedstock conditions on separating hydrogen isotopic water with emerging novel membranes remains unexplored. Here, the separation of H 2 O/D 2 O with graphene oxide (GO) composite membranes through vapour release close to actual conditions was investigated by vapour permeation processes from the perspective of temperature and vapour pressure of water feedstock: (i) for the temperature of 288 K, 303 K and 318 K,the highest separation factor of 1.40 was obtained under saturated water vapour pressure at 288 K; (ii) for 100 %, 75 % and 32 % of saturated water vapour pressure, permeation fluxes and separation factors decreased with the decrease of vapour pressure. Furthermore, the correlation of membrane structure-separation performance was reviewed with suggested possible ways to improve separation performance. The results demonstrate that the performance of H 2 O/D 2 O separation is linked with the temperature and vapour pressure of water feedstock conditions, which provides a good foundation for developing membrane processes to treat radioactive tritiated wastewater in the nuclear energy field.