Enhanced Capacities of Mixed Fatty Acid-Modified Sawdust Aggregators for Remediation of Crude Oil Spill

Mixed fatty acid-modified aggregators have been developed as potential crude oil sorbents. Cheap pine wood flour was first modified with oleic acid (OA) and further modified with second fatty acid by a leaving group chemistry, where a surface hydroxyl group is first replaced by p-toluenesulfonyl (p-Ts) group and a fatty acid forms a covalent bond on sawdust surface through esterification at the elevated temperature (55 C). Two OA-modified base materials, pine/OA-106 and pine/OA-124 with different OA-coverage were first prepared and the second fatty acids with C3, C6, C8, C10, C12, C14, or C16 alkyl chains were applied to cover the rest of surface hydroxyl groups. The crude oil sorption capacities of the mixed fatty acid-modified aggregators were studied and compared with those of the base materials. The results showed that mixed fatty acid-modified aggregators increased up to 45.6% more crude oil sorption than those of OA-modified base materials. A correlation between surface property and sorption capacity was studied by moisture sorption, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), 13C cross polarization and magic angle spinning nuclear magnetic resonance (CP/MAS NMR), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM).