MIT Researchers Use Electrochemical Method To Clean Water.
Relying on an electrochemical process, a team of researchers at Massachusetts Institute for Technology (MIT) have developed a new method to remove very dilute concentrations of pollutants and even extremely low levels of unwanted compounds from water.
Separation methods that existed before tend to consume a lot of energy and chemicals.
The study, titled “Asymmetric Faradaic systems for selective electrochemical separations,” was first published in the Royal Society of Chemistry’s journal Energy and Environmental Science.
The methods and systems that are being used in current water treatment plants and labs include membrane filtration, which, despite its high cost, has limited effectiveness at low concentrations, electrodialysis and capacitive deionization, which often require high voltages that tend to produce side reactions.
Adding to their shortcomings, these processes are hampered by excess background salts.
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, as the team demonstrated using ibuprofen and various pesticides.
Su argues that the same selective process should also be applied to the recovery of high-value compounds in a chemical or pharmaceutical production plant, where compounds might otherwise be wasted.
Matthew Suss, Assistant Professor of Mechanical Engineering at Technion Institute of Technology in Israel, who was not involved in this work, finds this technique as highly significant.

Food poisoning is a scourge.
Yet preventing it is far from foolproof.
But in a new study in Analytical Chemistry, scientists report that they are closing in on a way to use a combination of color-changing paper and electrochemical analysis — on plastic transparency sheets or simple paper — to quickly, cheaply and more accurately detect bacterial contamination of fruits and vegetables in the field before they reach grocery stores, restaurants and household pantries.
Of all the contaminants found in food and water, bacteria cause the most hospitalizations and deaths in the United States.
Nearly half of these incidents are attributed to spinach, cabbage, lettuce and other leafy greens, which are sometimes irrigated with unsafe water containing fecal material.
But traditional lab cultures take up to 48 hours to produce results, and other techniques such as DNA amplification and immunoassays are costly and are prone to false results.
Recently, Charles S. Henry and colleagues developed a paper-based method to detect Salmonella, Listeria and E. coli in food and water samples.
To simulate contaminated food, the researchers exposed clean alfalfa sprouts to E.coli and Enterococcus faecalis bacteria.
They also collected unfiltered water from a nearby lagoon.
For colorimetric detection, the team built a simple light box, which served as a substitute for a laboratory plate reader.