Clean Water Solution: MIT Develops New Electrochemical Method to Remove Micropollutants From Water

A team of researchers from the Massachusetts Institute of Technology has developed a new method capable of removing even tiny amounts of contaminants in the water.

The new method, described in a paper published in the journal Energy and Environmental Science, relies on an electrochemical process that has the ability to selectively remove organic contaminants, including chemical waste products, pesticides and pharmaceuticals, even at extremely low levels.

"The system could be used for environmental remediation, for toxic organic chemical removal, or in a chemical plant to recover value-added products, as they would all rely on the same principle to pull out the minority ion from a complex multi-ion system," explained Xiao Su, a postdoc at MIT and one of the authors of the study, in a press release.

At present, scientists clean contaminated waters using either membrane filtration, electrodialysis or capacitive deionization. Membrane filtration is expensive and has limited effectiveness at low concentration, while both electrodialysis and capacitive deionization require high voltages that may produce side reactions.

For the new system, the researchers used appropriately functionalized electrodes on both the positive and negative sides. The water between these functionalized surfaces coated with the so-called Faradaic materials.

Faradaic materials can undergo reactions to become positively or negatively charged. Additionally, these active groups can be tuned to make it bind strongly with a specific type of pollutant molecule, making it possible for the new system to remove such molecules even at parts-per-million concentrations.

By having the ability to run using power from solar panels, the new electrochemical system can be easily used to clean waters in the rural areas. Water purification systems are direly needed in the remote areas in developing countries, where pollution from pesticide, dye and other chemicals sipping through their water supply.

 Aside from removing pollutant molecule in waters, the researchers also noted that their new system can also help in the selective recovery of high-value compounds in a chemical or pharmaceutical production plant.