Researchers develop clog-resistant filtration system inspired by fish mouth

Inspired by the mouth structure of filter-feeding fish, researchers have developed a new fluid-filtering mechanism, which allows particles to be effectively trapped thanks to vortices in the fluids, according to a study published Tuesday in the journal Nature Communications.

Traditional filters work by screening the particulates out of the stream, and such filters need to be changed or cleaned frequently.

By comparison, the crossflow filtration design, developed by researchers at the College of William and Mary, works on the principle of concentrating the particulates. It directs and recirculates fluid flow through a structure that looks familiar to anyone who has peered down a fish's gullet.

The cone-shaped, 3D-printed, nylon plastic models are inspired by structures known as gill arches in the mouths of paddlefish and basking sharks. The researchers studied the models' activity in an experimental flow tank, as well as the mouth structure of three paddlefish specimens.

They find that the filtering structures in the models and the fish operate by creating vortices in the fluid that trap food particles and prevent clogging. The gill arches - bony or cartilaginous arches that support the gills - function as specific ribs that help to channel the flow of water in the fish mouth, creating currents and vortices. These ribs help to concentrate small particles, improving the efficiency of food capture, according to the study.

The findings may pave the way for more efficient industrial filters to be designed, potentially leading to more efficient filter processes.

"This is a great example of a biomimetic technology that could have significant advantages over the current state-of-the-art," said Jason McDevitt, director of technology transfer at the College of William and Mary. "We are particularly hopeful that this technology will be commercially developed and widely used for crossflow filtration."