The selective separation of trace components of interest from various mixtures (e.g., micropollutants from groundwater, lithium or uranium from seawater, carbon dioxide from air) presents an especially pressing technological challenge. Established materials and separation processes seldom meet the performance standards needed to efficiently isolate these trace species for proper disposal or re-use. To address this issue, researchers at UC Berkeley developed a novel separation strategy in which highly selective and tunable adsorbents or adsorption sites are embedded into membranes. In this approach, the minor target species are selectively captured by the embedded adsorbents or adsorption sites while the species transport through the membrane. Simultaneously, the mixture can be purified through traditional membrane separation mechanisms. As a proof-of-concept, the researchers incorporated Hg2+-selective adsorbents into electrodialysis membranes that can simultaneously capture Hg2+ via an adsorption mechanism while desalinating water through an electrodialysis mechanism. Adsorption studies demonstrated that the embedded adsorbents maintain rapid, selective, regenerable, and high-capacity Hg2+ binding capabilities within the membrane matrix. Furthermore, when inserted into an electrodialysis setup, the composite membranes successfully capture all Hg2+ from various Hg2+-spiked water sources while permeating all other competing cations to simultaneously enable desalination. Finally, using an array of other ion-selective adsorbents, the Berkeley team showed that this strategy can in principle be applied generally to any target ion present in any water source. This multifunctional separation strategy can be applied to existing membrane processes to efficiently capture targeted species of interest, without the need for additional expensive equipment or processes such as fixed-bed adsorption columns.