Biomimetic microfluidic pumps for selective oil–water separation

Abstract

Addressing the challenges posed by oil pollution from both domestic and industrial sources—which contributes to energy waste and environmental degradation—is critical. Here, a new, efficient, and sustainable oil/water separation system is presented using biomimetic spring microchannels created through precise projection micro-stereolithography-based 3D printing technique. This innovative system allows for the swift separation of mixed oil and water phases into distinct and pure streams, achieving a high separation flux of up to 292.5 L m−2 h−1. The separation efficiency, consistently maintained over 99%, leverages the synergistic effects of surface wettability and molecular polarity to handle multiple oils with varying densities and surface tensions. Moreover, the biomimetic microchannels precise capturing of the oil/water interface and offer flexibility to initiate separation by prefilling the channels with either oil or water. Furthermore, these microchannels effectively prevent clogging, ensuring sustained performance. A significant enhancement is also demonstrated in separating crude oil from water by solar irradiation to reduce its viscosity, with a notable separation rate of 22.5 L m−2 h−1 for individual channels. The findings underscore the potential of 3D bionic functional spring microchannels for selectively separating a wide range of oil-water mixtures with exceptional efficiency.