One-step foam assisted synthesis of robust superhydrophobic lignin-based magnetic foams for highly efficient oil-water separation and rapid solar-driven heavy oil removal. (April 2022) - Shi, Yunfen
Abstract: Taking effective measures to remove oil and organic pollutants from water has become a top priority. In this study, we developed a novel superhydrophobic and magnetic lignin-based polyurethane foam for highly efficient adsorption of organic pollutants and removal of viscous crude oil from water. The superhydrophobic bio-based magnetic foam was prepared by the addition of Fe3 O4 nanoparticles during the foaming process followed by the immersion in an octadecyltrimethoxysilane (OTMS) solution. After modification by OTMS, the water contact angle (WCA) of the foam adsorbent was increased by 37.1°, exhibiting a high WCA of 156°. Fe3 O4 nanoparticles endowed the foam with excellent photo-thermal performance, allowing the efficient adsorption of both crude oil and a wide range of organic solvents. The foam adsorbent had a high adsorption capacity up to 18.8 times of its own weight. The bio-based adsorbent could still retain a high adsorption capacity after over ten cycles. The magnetic property facilitated control and recycling of the foam adsorbent by using a magnetic field. Moreover, the bio-based foam adsorbent was fully degraded in a methanol/sodium hydroxide solution (0.5 mol/L) at 60 °C after 8 h. The outstanding mechanical stability, reusability, and environmental friendliness make these bio-based foam adsorbent highly promising for cleaning up pollutions in water. Graphical abstract: Unlabelled Image Highlights: Fe3 O4 nanoparticles were added during the foaming process. The foam showed a strong adsorption capacity for various oil and organic solvents. The foam exhibited an excellent magnetic response. Photothermal properties provided a potential solution for adsorbing crude oil. The degradation efficiency of the lignin-based polyurethane foam was 89.26%.