- Small robots actively chase nanoplastics instead of waiting for contact
- Electrostatic attraction allows nanobots to grab plastic-like charged surfaces
- Magnetic control allows precise movement without fuel or light.
There is a lot of plastic waste in the world, endangering the environment, and small particles of these plastics are now contaminating drinking water.
These particles, called nanoplastics, are so small that they can pass through conventional water filters, enter human organs and cause diseases such as cancer.
Researchers at Brno University of Technology have developed a small magnetic robot that can search for and remove these tiny particles from water.
Article continues below.
How tiny robots catch plastic particles
The research, published in Environmental sciences: nanodiscovered that these nanorobots use electrostatic attraction to remove nanoplastics in the same way a balloon sticks to hair.
“What’s striking is how these robots are designed to attract plastics electrostatically,” said Sylvain Martel, a computer engineer who was not involved in the work.
The robots come with hexagonal rods formed from iron-based organometallic structures, and each rod is about the width of a human hair.
Under a scanning electron microscope, each rod resembles a cratered meteorite, with pores that become places where nanoplastics adhere.
These rods were then heated, causing them to rearrange into magnetic compounds, allowing the robots’ movement to be controlled externally using magnets.
These robots operate using low-energy magnetic fields and require no additives, making them more efficient than designs that use fuels or ultraviolet light.
After removing the plastic, a simple magnet is used to attract the robots to the glass wall so that clean water can be poured.
Previous efforts to clean plastic using nanobots relied on passive capture, simply placing the robots in water and waiting for the nanoplastics to get close enough to stick.
The new study reverses that approach by sending robots to actively search for the particles.
“If it’s just particles waiting to attract nanoplastics, we don’t call it a robot,” said Martin Pumera, the lead researcher. “The idea is active matter.”
In laboratory tests, moving robots captured 78% of particles after one hour, about 60% more than when the robots were completely still.
Real world limitations
As robots are used for water cleaning, they degenerate, which is one of the problems with this technology.
Although an acid bath can regenerate the robots, their performance declines after four reuse cycles as the pores become clogged.
When tested in simulated seawater and groundwater, the robots’ efficiency dropped by about 70% because the dissolved ions competed with the nanoplastics for the robots’ electrostatic attraction.
Because robots move only a few micrometers per second and magnetic fields decay rapidly with distance, scaling them up is a challenge.
Conventional plants process millions of gallons per day, but these robots crawl so slowly that it would take an impractical amount of time to clean even a small fraction of that volume.
The dramatic drop in salt and groundwater efficiency also raises questions about real-world viability.
As interesting as this technology may seem, it is most likely a clever laboratory demonstration and not a scalable solution to the growing crisis of nanoplastic contamination in drinking water.
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