A snapping cavitation system inspired by pistol shrimp for bacterial water disinfection

A B S T R A C T Despite the established effectiveness of ultrasonic cavitation in sonochemical disinfection, energy demand and scalability constraints motivate alternative cavitation-based reactor concepts. Here, we report a hydrodynamic cavitation device inspired by the snapping mechanism of pistol shrimp for bacterial inactivation. An electric motor, speed reducer, and gear assembly actuate a claw-like element whose abrupt closure impulsively accelerates the surrounding liquid, generating periodic cavitating jets. Unlike conventional hydrodynamic cavitation reactors that rely on high-power pumping and large hydraulic circuits, the proposed configuration employs a compact mechanical architecture with moderate electrical input and no chemical additives. Cavitation develops within a confined chamber that promotes repeated pressure transients and localized energy concentration during collective bubble collapse. Experiments demonstrate effective inactivation of Escherichia coli at low initial concentrations. Although the dominant pathway cannot be conclusively identified, the observed inactivation is consistent with pressure-transient–mediated effects, potentially amplified by localized shear stresses and microjet formation near solid interfaces. These results support mechanically driven hydrodynamic cavitation as a promising bioinspired approach for further development and controlled optimization in water disinfection applications.