An Asymmetric Electrochemical System with ComplementaryTunability in Hydrophobicity for Selective Separations of Organics

摘要

Conducting polymers modified with redox-active moieties or amphiphilic surfactants are promising adsorbent materials for the separation of neutral organic species from water. We develop an asymmetric system combining a polyvinylferrocene–polypyrrole hybrid (PVF–PPy) and an amphiphilic surfactant dioctyl sulfosuccinate (AOT)-doped polypyrrole (PPy(AOT)) that have complementary hydrophobicity tunability in response to electrochemical modulations. Both materials are hydrophobic in their respective neutral states, exhibiting high affinities toward organics. Upon application of a mild potential to oxidize PVF–PPy and reduce PPy(AOT), these polymers can be simultaneously rendered hydrophilic, thereby driving desorption of organics and regeneration of the materials. The asymmetric system can be used in a cyclic fashion, through repeated electrical shorting of the two electrodes to program the capture of organics from a large volume of feed solution, and application of a potential (above 0.9 V) to stimulate the release of the adsorbed organics into a small volume of desorption solution.The asymmetric configuration has multiple benefits, including suppressionof water parasitic reactions, high energetic efficiency, and selectivityfor target organic species. Therefore, the electrode system has thepotential to reduce the energy consumption in the mitigation of organiccontaminants over conventional methods, with the additional abilityto recover valuable organic products, opening up new possibilitiesfor addressing the water–energy nexus.