Methods and systems for the separation of isotopes from an aqueous stream are described as can be utilized in one embodiment to remove and recover tritium from contaminated water. Methods include counter-current flow of an aqueous stream on either side of a separation membrane. The separation membrane includes an isotope selective layer (e.g., graphene) and an ion conductive supporting layer (e.g., Nafion). An electronic driving force encourages passage of isotopes selectively across the membrane to enrich the flow in the isotopes.

Methods for manufacturing an isotopic filtration module and methods for filtering water according to its isotopic forms. In some implementations, graphene oxide flakes may be dispersed in an aqueous medium to form a graphene oxide solution. The graphene oxide solution may be applied to a substrate to form a laminated graphene oxide membrane comprising a plurality of graphene oxide sheets coupled together in a layered, interlocking structure.

Methods for manufacturing an isotopic filtration module and methods for filtering water according to its isotopic forms. In some implementations, graphene oxide flakes may be dispersed in an aqueous medium to form a graphene oxide solution. The graphene oxide solution may be applied to a substrate to form a laminated graphene oxide membrane comprising a plurality of graphene oxide sheets coupled together in a layered, interlocking structure.

This lithium-isotope enrichment device comprises a treatment tank which is divided into a supply tank and a recovery tank by means of an electrolyte membrane having lithium ion conductivity, and recovers, into the recovery tank, an aqueous solution ES for the recovery of .sup.6Li of which the isotope ratio of .sup.6Li is high from a Li-containing aqueous solution FS stored in the supply tank. While a power supply, which is connected between a second electrode of a porous structure provided on a recovery tank-side surface of the electrolyte membrane and a third electrode provided to be spaced apart from the electrolyte membrane in the recovery tank, applies a voltage V1 with the second electrode being made to be positive, the lithium-isotope enrichment device connects a first electrode provided in the supply tank to the second electrode.

A lithium isotope concentration device includes a treatment tank partitioned in a supply tank and a recovery tank by an electrolyte membrane having a lithium-ion conductivity. The electrolyte membrane is cooled by a cooling device via an Li-containing aqueous solution in the supply tank to have a low temperature at which the Li isotope separation coefficient is larger. A power supply device, connected between electrodes provided on opposite surfaces of the electrolyte membrane, applies a positive voltage to an electrode on a supply tank side.