Researchers at MIT have devised a novel electrochemical process to selectively remove organic contaminants from water. This includes removing contaminants such as pesticides, chemical waste products, and pharmaceuticals, even when these are present in small concentrations.
The technique relies on a system in which water flows between chemically treated, or “functionalized,” surfaces that serve as positive and negative electrodes. These electrode surfaces are coated with what are known as Faradaic materials, which can undergo reactions to become positively or negatively charged. These active groups can be tuned to bind strongly with a specific type of pollutant molecule, as the team demonstrated using ibuprofen and various pesticides. The researchers found that this process can effectively remove such molecules even at parts-per-million concentrations.
Unlike previous studies that have generally focused on conductive electrodes, or functionalized plates on just one electrode, this technique focuses on appropriately functionalized electrodes on both the positive and negative sides, in an asymmetric configuration, which eliminated side reactions. Also, these asymmetric systems allow for simultaneous selective removal of both positive and negative toxic ions at the same time, as the team demonstrated with the herbicides paraquat and quinchlorac.