Abstract: The invention relates to semipermeable organomineral membranes usable in reverse osmosis.This organomineral semipermeable membrane comprises a porous inorganic material support coated with a vinylidene fluoride polymer or copolymer-based organic layer incorporating functional groups giving the membrane a permeability to water or other solvents.The porous inorganic material support is preferably constituted by a macroporous substrate coated with a microporous layer, e.g. produced from a single or mixed metal oxide or hydroxide. The organic layer can be constituted by polyvinylidene fluoride grafted by an appropriate monomer, such as styrene incorporating functional groups giving it selective permeability, e.g. hydrophilic groups, such as sulphonic groups.

Abstract: The invention relates to a process for the production of porous, permeable, mineral membranes.According to this process, on a porous, permeable substrate is formed a thin layer of at least one mineral compound chosen from among the simple or mixed metal oxides, except aluminum oxide and mixed aluminium oxides, simple or mixed metal hydroxides, except aluminium hydroxide and mixed aluminium hydroxides and mixtures thereof on the basis of a suspension in a liquid of colloidal or non-colloidal particles, said compound or a precursor thereof having particle sizes below 10 .mu.m. The suspension is kept in the finely divided state by the continuous application of energy to the reaction medium. The thus obtained membrane is dried and then annealed at a temperature between 400.degree. and 1100.degree. C.The use of a suspension of ultrafine colloidal or non-colloidal particles makes it possible to obviate the compression stage and obtain microporous layers with very small pore radii.