Skimming mechanism of hydrophilic teeth for microplastic (MP) balls. The neighbouring concave meniscus induces the Cheerios effect, causing the MP ball to naturally move toward the teeth. The schematic shows the skimming process of the MP ball with periodic deformation of the water meniscus. The skimmed MP balls are subsequently held firmly within the water-bridged teeth (by the water bridge) by capillary adhesion. Credit: Korea Institute of Science and Technology.
Scientists have created hydrophilic tooth technology which further develops microplastic recovery technology using floating drones.
In recent years, microplastics have garnered significant attention due to their detection in tap and bottled water, as well as in rivers, lakes, and oceans.
Conventional filtering technologies for water treatment have difficulty effectively filtering out microplastics of various sizes and shapes and are prone to clogging.
Additionally, recovering small particles requires extremely fine filter meshes, which increases pressure and drastically reduces filter efficiency.
Furthermore, they are not effective in open spaces such as lakes, rivers, or oceans, where microplastic pollution is increasing.
Prototype of a floating drone with hydrophilic ratchet technology (marine robotic cleaner). The successive images depict a lab-scale prototype equipped with a ratchet-structured drum, skimming microplastics of various sizes as it moves forward. The left image shows a floating drone designed for cleaning open waters, while the right image features a handheld, portable version for manual cleaning in marinas or near shorelines. Credit: Korea Institute of Science and Technology.
Floating drone
Dr Seong Jin Kim and Myoung-Woon Moon of the Center for Extreme Materials Research at the Korea Institute of Science and Technology (KIST) have developed a new level of microplastic removal technology, offering a promising solution to this growing problem.
They have developed a floating drone equipped with hydrophilic tooth structures that leverage surface tension to skim microplastics.
The core of the team’s approach is the hydrophilic ratchet structure.
This design forms a water bridge that forms between the teeth due to its affinity for water, which maximises the surface tension of the water to adhere the microplastics to the teeth.
This approach enables the removal of microplastics ranging in size from 1 micrometre (μm) to 4 millimetres, addressing the challenges traditional filtering technologies face with size and shape variability.
It also ensures reliable operation without the risk of clogging.
The technology has achieved over 80% recovery efficiency for various types of microplastics, including expanded polystyrene, polypropylene, and polyethylene.
In particular, the hydrophilic ratchet structure of the floating drone can be used to remove microplastics in real-time in large bodies of water such as oceans, lakes, and rivers.
The drone can move autonomously and purify water quality like a household robot vacuum cleaner, showing its versatility beyond the limitations of existing fixed systems
Moon said: “This technology can be applied not only to floating drones, but also to stationary systems such as water treatment filters in aquaculture farms.
“It can also be expanded into a home water treatment filter device that individuals can use in their daily lives.”
The research is published in Advanced Science.
