Wastewater is often polluted with heavy metals such as copper that could actually be of use, but the problem is that we haven’t had a way to separate these metals from the other contaminants in the water. Today’s wastewater cleaning process simply pulls out everything from nutrients and essential minerals to heavy metals and other contaminants out of the water, leaving behind a toxic sludge.
All of this could soon change, however, after a team of scientists developed a new technology that can target and trap only the copper ions in wastewater, opening the doors to a new way to source important metals sustainably. The new technology, which was developed by scientists at the Department of Energy’s Lawrence Berkeley National Laboratory, works “kind of like a crystal sponge.”
“When you put it into the water, it opens up,” says Jeff Urban, the director of the Inorganic Nanostructures Facility in the Berkeley Lab’s Molecular Foundry. “Instead of grabbing everything, this is a sponge that’s very specific to copper because of the size of the pores and the stickiness of the pores for copper.”
In a new journal article, the authors state that the sponge material, called ZIOS (zinc imidazole salicylaldoxmine), could be used to extract copper in the acidic water coming from a copper mine. Once ZIOS is filled with copper, the copper can simply be reused, allowing the sponge to be reused again.
Although scientists have started by targeting copper, the material can also be designed to capture other metals in water such as lithium, a key material for making the batteries used in electric cars. The study suggests that wastewater treatment plants could eventually use filters made from ZIOS that could capture different metals simultaneously, pulling each metal into a different channel.
If this is done at a large scale, it could just become an important source for new metals that don’t require any mining. And because the material is less expensive than other methods of removing pollutants, there’s actually a good chance this new technology gets scaled up.