Aluminum soap nanoparticles-lignin powder form phase-selective gelator: synergistic adsorption and gelation for rapid oil spill recovery

Abstract Rapid and effective recovery of the oil spill is extremely challenging during oil spill remediation. To meet this challenge, an organogelator-polymerized porous matrix composed of adsorbents and organogelators provided a new strategy. This work investigated the gelling mechanism of aluminum 12-hydroxystearate (Al HSA) to form spherical nano micelles in solvents via UV-vis, FT-IR, and XRD. We creatively proposed a method for saponification of 12-hydroxystearic acid (HSA) on lignin via epichlorohydrin (ECH) crosslinking to produce aluminum soap-lignin gelator (OTS-AL/Al HSA). By adjusting the ECH content, Al HSA nanoparticles (15-40 nm) were grown on lignin, which improved the roughness endowing lignin with better hydrophobicity (WCA 134.6°) before octadecyltrichlorosilane (OTS) modification. Oils and organic solvents could be rapidly adsorbed by OTS-AL/Al HSA gelator at low temperatures due to the abundant pore structures. Rheological studies demonstrated its gelation characteristics, which were attributed to the rapid absorption of oils by lignin and the self-assembly of Al HSA nano micelles on lignin to form an aggregated network structure trapping oils, thus realizing the synergistic effect of oil adsorption-gelation. Recyclable materials, easy preparation process, and excellent oil treatment capacity make this new biomaterial may inspire more research in oil spill remediation in the future.