Cotton Fiber-Based Sorbents for Treating Crude Oil Spills

Wood and plant fibers have been studied as natural sorbent materials for treating aquatic oil spills; however, the effectiveness of these materials is limited by their tendency to absorb water as well as oil. Chemical pretreatment of cotton fibers with fatty acids was examined as a means of enhancing the performance of cotton as a sorbent for crude oil. A raw cotton fiber was chemically modified with C18 fatty acid by simple leaving group chemistry. Free surface hydroxyl groups were modified with long alkyl chains to create fibers that displayed increased water contact angles, indicative of a significant decrease in surface energy. The increased affinity for oil and corresponding repulsion of water on the individual modified fibers translated to greater sorption of oil and rejection of water by loose assemblies of fibers (i.e., balls or yarn) when compared with unmodified cotton. X-ray diffraction (XRD) pattern, Fourier transform infrared (FT-IR), ¹³C cross-polarization/magic angle spinning solid-state nuclear magnetic resonance (CP/MAS SSNMR), and scanning electron microscopy (SEM) showed that cotton fibers were significantly exfoliated by the intercalation of C18 fatty acids about 2.4 times in its diameter. In the presence of seawater, the highly oleophilic C18 fatty acid-modified cotton fiber showed a maximum oil sorption capacity of 35.58 g per gram of fiber, about ∼49% greater than that of the corresponding raw cotton fiber.