Regeneration of liquid membrane without breaking emulsion

Abstract

A process for removing a species from a fluid which comprises (a) contacting said fluid with an emulsion, said emulsion having an external phase and an internal phase, said external phase being immiscible with said fluid and said species being permeable to said external phase; (b) permeating said species through said external phase into said internal phase; (c) converting said permeated species in said internal phase, into a species which is impermeable to said external phase; (d) separating said emulsion from said fluid; (e) converting the impermeable species of step (c) into a species which is permeable to said external phase by means of an oxidation-reduction reaction; and (f) permeating the permeable species of step (e) through said external phase. The instant process may be carried out in the reverse manner, i.e. the fluid including the species to be removed can be the internal phase of an emulsion or foam and thus permeate through the external phase. Preferably the fluid is an aqueous solution and the emulsion is a water-in-oil emulsion. The impermeable species of step (c) may be converted into a species which is permeable to said external phase by irradiating with light (UV or visible), by heating or by isolating said impermeable species from light. Preferably the permeable species in the internal phase is U.sup.+6 e.g. as UO.sub.2.sup.+2, which is trapped in the internal phase of the emulsion by reduction to U.sup.+4 an impermeable species, in the presence of a hydroquinone and light. Simultaneously hydroquinone is converted to quinone. After separation of the emulsion containing uranium in the +4 nonpermeable state from the aqueous solution, the emulsion is subjected to agitation in the presence of a fresh aqueous solution and in the absence of light whereby the quinone oxidizes the U.sup.+4 to U.sup.+6 e.g. UO.sub.2.sup.+2 which then permeates through said external phase into said fresh aqueous solution.