Antigravity Autonomous Superwettable Pumps for Spontaneous Separation of Oil-Water Emulsions

Oil-water separation based on superwettable materials offers a promising way for the treatment of oil-water mixtures and emulsions. Nevertheless, such separation techniques often require complex devices and external energy input. Therefore, it remains a great challenge to separate oil-water mixtures and emulsions through an energy-efficient, economical, and sustainable way. Here, a novel approach demonstrating the successful separation of oil-water emulsions using antigravity-driven autonomous superwettable pumps is presented. By transitioning from traditional gravity-driven to antigravity-driven separation, the study showcases the unprecedented success in purifying oil/water from emulsions by capillary/siphon-driven superwettable autonomous pumps. These pumps, composed of self-organized interconnected channels formed by the packing of superhydrophobic and superhydrophilic sand particles, exhibit outstanding separation flux, efficiency, and recyclability. The findings of this study not only open up a new avenue for oil-water emulsion separation but also hold promise for profound impacts in the field. It is demonstrated for the first time that unsuccessful gravity-driven oil-water emulsion separation can be very successful if the separation manner is changed to antigravity-driven by using autonomous superwettable pumps with the ability of antigravity liquid transportation. Such antigravity pumps composed of self-organized interconnected microchannels can purify oil and water phases from oil-water emulsions spontaneously. image