Cooperative recyclable magnetic microsubmarines for oil and microplastics removal from water

Abstract In recent times, water pollution by leaked oil and plastic microparticles has attracted widespread attention, and their efficient removal demonstrates great challenges. Here, we report a ”hedgehog” magnetic microsubmarine based on sunflower pollen grains (SPGs), which holds great promise in removing oil and microplastics pollution simultaneously. These hollow microsubmarines were fabricated on a large scale by sequentially treating the natural SPGs with acidolysis, sputtering. The hollow structure allows a double functionality: (i) like a submarine, propel under or above the water, depending on the fillings inside; (ii) oil pollution storage. The microsubmarine can not only transport oil droplets 37 times larger than its own volume, but also effectively adsorb floating oil via capillary action. And the fluid induced by the cooperative microsubmarines can remove the microplastics controllably in a noncontact method. What’s more, their cooperative behavior can further enhance the transport capacity and improve the decontamination efficiency. These microsubmarines with structural stability and physicochemical robustness provide a promising approach for water repair applications.