Separation process utilizing microcapsules

Abstract

The instant invention relates to a process for removing a species from a fluid which comprises (a) contacting said fluid with a hollow microcapsule, said microcapsule having a wall surrounding an internal void, said wall being substantially insoluble in said fluid and said species being permeable to said wall; (b) permeating said species through said wall into said void; (c) converting said permeated species, in said void into a species which is impermeable to said wall; (d) separating said microcapsule from said fluid; (e) converting the impermeable species of step (c) into a species which is permeable to said wall; and (f) permeating the permeable species of step (e) through said wall. Preferably said void contains a reagent which together with said permeated species form a reversible oxidation-reduction couple. In the instant preferred embodiment said permeated species is converted into an impermeable species by means of said oxidation-reduction reaction to trap said impermeable species in said void. The spent microcapsules, i.e. microcapsules are no longer capable of converting the permeable species of step (c) into an impermeable species, are regenerated by reconverting the impermeable species into a permeable species by reversing such oxidation-reduction reaction by means of heat, light, or the absence of light. The instant process is particularly preferred for separating multivalent metal ions from aqueous solutions.