Rare earth elements are used in many advanced technologies, including permanent magnets, supercapacitors, superconductivity, and sustainable energy systems. Solvent extraction processes to separate and purify rare earth ions from multi-component aqueous mixtures involve placing the aqueous phase in contact with an organic phase containing amphiphilic extractant molecules that interact with the targeted ions and transport them into the organic phase for further processing. Extractants are believed to complex with ions at the interface, and recent studies have suggested that complexation of ions with extractants in the bulk aqueous phase is not advantageous to the intended extraction. Nevertheless, other molecules, denoted aqueous complexants, are utilized to complex with specific ions in the bulk aqueous phase, preventing them from interacting with extractants and being extracted into the organic phase. This has been used to advance the separation of actinides and lanthanides, where complexants such as DTPA hold back actinides in the aqueous phase while lanthanides are extracted into the organic phase. The competing effects of extractants and complexants contribute to the equilibrium distribution of ions in bulk and interfacial liquids. The concentration and type of extractants and complexants, as well as the pH, temperature, the choice of solvents, and the target ions are the primary variables used to control extraction. Kinetics (diffusive or molecular) can also enhance the fractionation of ions. Here, we introduce another variable and demonstrate that the equilibrium ion distribution can be altered by exposing the bulk liquid to X-rays, thereby producing a controllable and reversible transport of ions between bulk liquid and a liquid-vapor interface. It is known that aqueous radiolysis produces H and OH radicals, as well as hydrated electrons that react with a wide range of solutes, which have been implicated in the reprocessing of nuclear fuel. These products of aqueous radiolysis are likely responsible for the effects reported here.