Electrochemical Technique Zaps Tiny Amounts of Pollution from Water

When removing very low concentrations of pollutants from water, existing methods can be very energy- and chemical-intensive. A new method developed at MIT could be an alternative for removing even extremely low levels of unwanted compounds. The system relies on an electrochemical process to selectively remove organic contaminants like pesticides, chemical waste products, and pharmaceuticals. In the new system, the water flows between chemically treated surfaces that serve as positive and negative electrodes. These electrode surfaces are coated with 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. The MIT researchers found that this process can effectively remove such molecules even at parts-per-million concentrations.

Transcript

00:00:00 Removing pollutants from water is the ultimate goal of the purification process. However, current methods of removal have their share of complications. And tend to be quite energy and chemical intensive, especially when it involves removing contaminants at extremely low levels. But now a team of researchers at MIT have developed a new system that could

00:00:29 provide an alternative for removing specific, unwanted, compounds. And their new system is controlled solely by electrical means. The novel approach relies on an electrochemical process to selectively remove organic contaminants such as pesticides, chemical waste products, and pharmaceuticals from the water, even when these contaminants are present in small, but still dangerous, concentrations.

00:00:53 Their system of removal involves two main parts, chemically treated surfaces, and electricity. Here's how the system works. First, surfaces are coated with water known as Faradaic materials, which are materials that can undergo reactions to become positively or negatively charged. Then an electrical source is added. As water flows between these now chemically treated electrodes, the surface materials can be tuned

00:01:16 to bind strongly with a specific type of pollutant molecule. Here we see the system at work removing a pollutant represented by the green fluorescence. Over time, the surfaces are tuned, and thus become bound, to specific molecules until the water color goes from bright fluorescent green to clear. The researchers say that systems such as this might ultimately be useful for water purification systems in remote areas in the developing world, where access to resources and power are limited.

00:01:43 For example, the new, highly efficient, electrically operated system could run on power, from solar panels.