Self-Driven Sustainable Oil Separation from Water Surfaces by Biomimetic Adsorbing and Transporting Materials

Abstract

Oil films on water are an increasingly major contamination problem worldwide. In 2020, we published a novel adsorption and transportation technology for oil–water separation based on biological role models like the floating fern Salvinia. This application provides an unexpected ability for the fast and efficient removal of oil films, particularly in ecologically important freshwater biota. A single small Bionic Oil Adsorber (BOA) with 1 m2 functional textile can collect up to 4 L of oil per hour, which equals about 100 m2 of oil film from a water surface into a collecting vessel. This is a safe, fast, and sustainable solution for the ubiquitous contaminations of, e.g., fuel oil in freshwater environments. Here, we present updated, new experimental data, and a review of the literature published since.

Bio-Inspired Textiles for Self-Driven Oil–Water Separation—A Simulative Analysis of Fluid Transport

“…The fastest transport takes place in the leaf areas where the distance between the trichomes is small [8]. The narrower spacing leads to higher capillary forces and thus to faster oil transport [10].…”

“…With the textile produced in this way, it is possible to transfer all functional aspects of superhydrophobic surfaces for oil-water separation into technology. The textile can be integrated into the BOA and, in its current prototype state, enables the removal of 4 L of diesel within one hour (see Video S1 for the oil adsorption in the bioinspired textile) [10]. With the textile produced in this way, it is possible to transfer all functional aspects of superhydrophobic surfaces for oil-water separation into technology.…”

“…This approach results in a non-toxic, user-friendly, and versatile process for sustainable oil spill cleanup without additional energy input or waste generation. The outcome of this effort is a novel physical method for removing oil films from water surfaces, realized through a device known as a bionic oil adsorber (BOA) [8,10]. The BOA is a floating oil collector whose main components are a vessel and a technical surface inspired by the phenomenon seen in Salvinia.…”

“…The oil is adsorbed and transported by the BOA textile (red arrows). As shown in the cross-section, it enters the container, where it is released again and accumulates at the bottom of the container [10].…”

“…Compared to these adsorption materials, the principle of BOA is characterized above all by the fact that it can be reused several times, the oil is collected directly, and the adsorption quantity is not limited by the size of the adsorption material. The latter is due to the fact that the bio-inspired material serves as a transport medium and does not just store the removed oil [10].…”