The robot imitates the undulating motion of the snails’s underside to drive water surface flow and suck in floating particles.
Plastic pollution poses a clear and present danger to ecosystems and an especially insidious form of it involves microplastics. These tiny plastic particles can accumulate in the tissues of animals, including us, and can even breach the blood-brain barrier with potentially grave consequences for health.
Scientists have been trying to work out ways to clean up the environment through creative means. Recently scientists have proposed adding natural plant compounds known as tannins to a layer of wood dust to create a filter that traps nearly all microplastic particles in water.
Now another team of researchers in the United States is proposing another solution: a robot based on the Hawaiian apple snail (Pomacea canaliculate).
The snail employs “the undulating motion of its foot to drive water surface flow and suck in floating food particles,” according to the researchers. It is this feature that intrigued them and their protype can scoop up microplastics by imitating the snails in their movement.
Such robots could one day be deployed to the surfaces of oceans, seas and lakes, the researchers say, although for that to happen their prototype will need to be scaled up for real-world settings.
“We were inspired by how this snail collects food particles at the water and air interface to engineer a device that could possibly collect microplastics in the ocean or at a water body’s surface,” explains Sunghwan Jung, a professor at the department of biological and environmental engineering at Cornell University.
The researchers used a 3D printer to make a flexible carpet-like sheet that can undulate in the style of the snail’s underside. They achieved this with a sheet that rotates like a corkscrew and causes the carpet to undulate and thereby create a travelling wave on the water.
“The fluid-pumping system based on the snail’s technique is open to the air,” the scientists note, adding that “a similar closed system, where the pump is enclosed and uses a tube to suck in water and particles, would require high energy inputs to operate.”
Not so their snail-like open system, which is far more efficient. Their prototype runs on only 5 volts of electricity while still effectively sucking in water, according to Jung. Obviously a far larger model would need far more energy and the scientists propose attaching a floatation device to the robot to keep it from sinking. Solar panels could provide the electricity for it.
Creative solutions like these will be key to reducing the vast quantities of microplastics in the oceans, seas and lakes. One recent study, for instance, has found that all the lakes surveyed for the research have been contaminated with microplastics.