All living organisms need heavy metals like zinc and iron to survive and properly function. But increasingly, metals from industrial waste, mining, landfills, and even overcrowded cemeteries are leaching into the environment and contaminating it. Exposure to heavy metals like arsenic, cadmium, and lead—even at low concentrations—can seriously threaten human health and the planet’s biodiversity.
One solution to this type of contamination may be tiny robots. In a study published Tuesday in the journal Nature Communications, researchers at the University of Chemistry and Technology in Prague have created magnetic, temperature-sensitive nanorobots that can pick up and dispose of pollutants in water.
In recent years, scientists have been greatly interested in harnessing nanotechnology to address water pollution and wastewater treatment. Conventional water treatment systems often require multiple, complicated steps to clear contaminants out of water. And many of these steps leave behind many pollutants like metals. Some novel nanomaterials get around this problem by utilizing a high surface-to-volume ratio and by targeting specific toxins.
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Using nanorobots to clean up the sludge isn’t exactly a cakewalk. One problem with using these tiny, synthetic janitors is that the motors that propel them—which often rely on non-toxic metal catalysts—degrade easily, giving the nanorobots a short lifespan.
The Prague team found a way to get around that problem by magnetizing the nanorobots with iron oxide nanoparticles and coating them in a material called pluronic triblock copolymer (PTBC) that responds to temperature changes. As the heat goes up, the PTBC becomes chemically attracted to the pollutants—it can act as the tiny robots’ “hands,” and basically pick up and carry pollutants out of the water.
In their study, the researchers found that when these PTBC-coated, magnetized nanorobots were placed into a solution containing the heavy metal arsenic and atrazine—a synthetic herbicide found in over 300 products—the nanorobots were able to roundup nearly all the toxic chemicals present.
A simple magnet is all you need to remove the nanorobots from the water. When cooled, they unload their collected pollutants, much like a garbage truck unloading at a landfill.
It may be a while until temperature-sensitive, magnetic nanorobots are regularly used for environmental clean-up. But a scaled-up version could revolutionize clean water systems and remove heavy metal pollution exacerbated by human activity, including for a larger array of harmful metals. Hard to believe something so little could boast so much potential.
