USV with Interfacial Pumping for Efficient Microplastics Removal

Abstract

Microplastics that accumulate at the air–water interface pose urgent ecological and health risks. However, existing sampling and collection methods based on surface trawls are hindered by hydrodynamic resistance. We present the first in-motion characterization of an interfacial pump mounted on a small uncrewed surface vehicle (USV) to actively draw surface water into an onboard filter. Experiments combining thruster-driven forward motion with the undulating pump show that low thruster output and moderate pumping frequency maximize particles captured per unit energy, balancing the ram effect of forward speed with the lateral suction of the pump. Scaled towing tests reveal that the pontoon cross-section strongly influences intake flow, indicating that streamlined profiles can further boost filtration efficiency. Finally, flow-visualization confirms that the pump’s ability to generate far-field suction without bulk mixing (previously demonstrated only in static tests) persists while the USV is in motion. These results establish interfacial pumping as a promising bio-inspired strategy for manual and autonomous microplastics collection, and highlight design parameters that can guide future development of distributed, high-coverage sampling platforms.