Clean water is a basic necessity for life, and researchers at Massachusetts Institute of Technology (MIT) have come up with a new method to clean up water, a lot of which is contaminated with various pollutants — some of them toxic — all over the world. The new process relies on electricity but uses less power than other comparative methods.

The development of the new technique to remove contaminants from water was led by Xia Su, a postdoctoral researcher at MIT working on wastewater purification. The method relies on an electrochemical technique. Special polymers are applied onto electrodes to bind strongly with specific pollutants (changing the polymer will change what impurities are removed) and the electrodes — one positively charged and the other negatively — are placed inside the polluted water.

When electricity passes through the electrodes, it creates an electrical circuit (water being an excellent conductor) which attracts the contaminant ions, thus purifying the water. Since the chemical binding is very specific, it also catches material present in trace amounts, which, depending on the specific impurity, can be dangerous even in small doses.

In the example in the video, the green liquid gets its color from a pharmaceutical pollutant, and after being put through Su’s purification process, about 95 to 98 percent of the pollutant was removed from the water. Su said leaving the process running for longer would reduce the amount of impurities further, possibly cleaning the water enough to make it drinking quality.

Similar methods are already in existence, but the MIT researchers say their method is superior because it is comparatively energy-efficient and produces hardly any byproducts.

Su and his colleagues are already working with agricultural partners in the United States to clean up streams that agricultural waste, like fertilizers and pesticides, flows into. They hope to also target industrial wastewater in the future.

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