Abstract: A process for the extraction of hydrogen sulphide from a gas mixture comprises: a step (a) in which the gas mixture is passed into an aqueous acidic solution of copper sulphate under conditions which lead to the formation of copper sulphide; a gas which is highly depleted in hydrogen sulphide and an aqueous phase containing copper sulphide in suspension are recovered; a step (b) in which the copper sulphide contained in suspension in the aqueous phase from step (a) is oxidised using an oxygen-containing gas under conditions which lead to the formation of solid elemental sulphur and soluble copper sulphate from this liquid phase; and a step (c) in which the solid sulphur and the solid copper sulphide which is not transformed during step (b) are separated and at least a portion of the aqueous acidic phase containing the copper sulphate formed during step (b) is optionally recycled to step (a).The process is used to absorb hydrogen sulphide contained in a variety of industrial gases.

Abstract: A gas separation membrane, comprising a film with a thickness ranging from 0.05-10.sup.-6 to 20.10.sup.

Abstract: Disclosed is a gas separation membrane, comprising a film with a thickness ranging from 0.05.10.sup.-6 to 20.10.sup.-6 m, at least 90% by mole of which is at least one aromatic polyimide or copolyimide, the recurrent unit of which corresponds to the following formula (I): ##STR1## where A represents a tetravalent aromatic radical at least 50% by mole of which are represented by the following formula (II): ##STR2## and B represents a bivalent aromatic radical or a mixture of bivalent aromatic radicals.