Materials: Nanorobots remove water pollutants

Magnetic and temperature-sensitive nanorobots that can remove pollutants from water are reported in a paper published in Nature Communications. The findings could guide the design of sustainable technologies for the removal of chemical pollutants from water.

Heavy metal ions and pesticides are contaminants that can be found in water, and developing efficient methods for their removal is desirable as they are harmful to the environment. Artificial nano-and micro-motors have been suggested as methods for pollution removal, but current catalytic motors degrade easily, which can restrict their lifespan.

To overcome this challenge, Martin Pumera and colleagues developed thermosensitive magnetic nanorobots. The nanorobots consist of a temperature sensitive polymer (pluronic triblock copolymer (PTBC)) that functions like miniature hands to ‘pick up’ and dispose of pollution, and iron oxide nanoparticles that make the robots magnetic.

The authors found that the nanorobots could remove the heavy metal arsenic and atrazine (a common herbicide) from water. They demonstrate that pollutant uptake/release is regulated by temperature. At 5°C, the nanorobots scattered in water but aggregated when the temperature was raised to 25°C, trapping the pollutants. The authors could then remove the nanorobots from the water using magnets. Cooling the material caused the nanorobots to separate and unload the pollutants, so the nanorobots could then be reused.