Scientists in the Czech Republic have developed microscopic robots that can actively move through both water and water-saturated soil to collect microplastic particles. The devices are built from ultrathin MXene flakes coated with magnetic nickel nanoparticles, giving them a high-surface-area sticky exterior and the ability to be steered by external rotating magnetic fields.
In a study published in NPG Asia Materials, the researchers introduced swarms of these microrobots into contaminated water and model soil samples. The magnetic fields caused the robots to spin and tumble, allowing them to navigate through liquid and squeeze through tiny water-filled pores in the soil matrix.
As the robots moved, their surfaces collided with microplastic particles, binding them and dragging them along. After a collection period, a magnet was used to retrieve the robots together with their captured plastic cargo.
In water, the system removed approximately 94% of polystyrene particles and 89% of polyethylene terephthalate (PET) within about one hour. In the model soil, removal rates were approximately 81% for polystyrene and 72% for PET.
The active magnetic propulsion outperformed the same MXene material used without motion, which relied only on passive adsorption. The authors note that the microrobots can disrupt microplastic entrapment within soil structures, a key challenge for conventional cleanup methods.
The experiments were conducted under controlled laboratory conditions. The researchers acknowledge that field trials will be necessary to assess performance in real-world environments, and that potential risks such as metal-ion leaching and incomplete magnetic retrieval must be addressed before practical deployment.
Swarms of tiny robots remove microplastics from soil and water
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