Researchers at MIT have drawn inspiration from manta rays and their unique filter-feeding mechanisms to improve the design of industrial water filters. In a recent study published in Proceedings of the National Academy of Sciences, engineers analyzed how mobula rays—a family of aquatic rays that includes manta and devil rays—efficiently filter plankton while swimming.
Mobula rays filter food by letting water flow into their mouths and through comb-like plates along the floor of their mouth. These plates create vortices that trap plankton and prevent it from escaping, even when the particles are smaller than the gaps between the plates. The researchers found that these vortices play a crucial role in maintaining the delicate balance between permeability (allowing water to pass through) and selectivity (trapping particles effectively).
Inspired by this natural system, the engineers designed a prototype “leaky channel” filter, mimicking the ray’s plates with 3D-printed structures. By pumping water through the filter, they observed that slower flows allowed water and particles to pass through easily, but faster flows created vortices that blocked particles while letting water escape. This mechanism provided a blueprint for optimizing cross-flow industrial filters, commonly used in water treatment plants.
This biomimetic approach offers practical solutions for industries requiring efficient filtration. By adjusting parameters like flow rate, pore diameter, and spacing, designers can create filters that strike the optimal balance between energy efficiency and particle retention. Lead researcher Dr. Xinyu Mao emphasized that the mobula ray offers “a rule of thumb for rational design.”
This work, supported by the National Institutes of Health and the Harvey P. Greenspan Fellowship Fund, highlights the potential of biomimicry in addressing critical challenges like water filtration. With manta ray-inspired designs, the future of clean water technology could be both more efficient and environmentally conscious.