Heavy metal, as in the music and the cartoon movie with all the boobs, is still cool. (YES IT IS.) But heavy metals, as in heavy metals, are not very popular on account of being toxic. Luckily engineers at Brown are also cool (YES THEY ARE), and have devised a new way to remove heavy metals from Superfund sites and developing countries.
In experiments, the researchers showed the system reduced cadmium, copper, and nickel concentrations, returning contaminated water to near or below federally acceptable standards. The technique is scalable and has viable commercial applications, especially in the environmental remediation and metal recovery fields.
The researchers' solution is a good example of good old fashioned tinkering, and while it doesn't constitute a breakthrough, it does something just as useful. It effectively combines existing technologies in a way that's scalable and affordable.
A process that is seriously called “electrowinning” has already been proven effective in removing heavy metals from water, but only if the metal ions are in high enough concentration. So the Brown device uses an acid or base to change the pH of contaminated water, which separates out the heavy metals into a solid precipitate. By doing this over and over again to incoming batches of dirty water (the clean water is siphoned off between cycles), the device can raise the concentration of metal ions in the water to a high enough level that it can be removed by electrowinning.
Then the electrowinning takes over. An electric charge running through the water concentrates the metals even more effectively than a chemical process can, and without the toxic byproducts that chemical processes create. Once the metals are concentrated enough, they’re easy to filter out of water.
The result is water with heavy metal contamination near or below maximum levels established by the EPA, which sounds kind of meh until you compare it to water with heavy metal contamination WELL IN EXCESS of maximum levels.