Abstract: The invention relates to a process for separating sodium from aqueous effluents resulting from the reprocessing of spent nuclear fuel elements. According to the invention, the effluent (3) is introduced into a tangential filtration module (11), whose membranes are made from polyaramide, sulphonated polysulphone or perfluorinated ionomer, so as to collect a permeate P containing sodium, depleted in radioactive elements and a retentate R enriched in radioactive elements.

Abstract: The invention relates to a reverse osmosis or nanofiltration membrane and to its production process. This membrane comprises a porous support made from an inorganic material coated on one face with a first mesoporous inorganic material layer, e.g. of TiO.sub.2, having a mean pore radius below 10 nm and a second active layer, having a thickness of 0.1 to 1 .mu.m, made from sulphonated polysulphone, polybenzimidazolone, grafted polyvinylidine fluoride or Nafion..RTM.

Abstract: An ultrafiltration, hyperfiltration or demineralization element comprises a porous inorganic material support and an asymmetrical, cellular, microporous organic polymer membrane, produced on one of the faces of the porous support and fitted into the pores of the porous support flush with said surface and without projecting beyond the same.The element is prepared by coating the inner surface of a tubular porous support with a coating solution of the organic polymer and then subjecting the coated support to a polymer insolubilization stage, which can be carried out by partial evaporation, followed by the immersion of the coated support in a coagulating bath.