Bio-based kapok fiber-coconut husk composite aerogel: A sustainable solution for marine oil spill remediation.

Marine oil spills pose a critical threat to aquatic ecosystems, necessitating mitigation technologies that are effective, durable, biodegradable, and environmentally benign. In this study, a bio-based composite aerogel was fabricated from agro-waste kapok fibers and coconut husks, introducing a dual-fiber design that leverages their synergistic lignocellulosic properties. The fabrication process involved fiber gelation with polyvinyl alcohol as a binder, solvent exchange, and freeze-drying, followed by hydrophobic surface modification using dodecyl trimethoxy silane. The aerogel was characterized by Fourier-transform infrared spectroscopy to confirm chemical modifications and by scanning electron microscopy to examine its morphology. Nitrogen adsorption-desorption analysis revealed a Brunauer-Emmett-Teller surface area of 428 m2/g, while mechanical testing showed stability up to 73 kPa. The aerogel also exhibited enhanced hydrophobicity with a water contact angle of 118°. Oil sorption experiments using diesel and engine oil (SA40) demonstrated sorption capacities of 8.46 ± 0.44 g/g (15 min) and 9.22 ± 0.30 g/g (24 h) for diesel, and 5.41 ± 0.26 g/g (15 min) and 7.52 ± 0.24 g/g (24 h) for engine oil. The superior performance is attributed to the synergistic effects of the porous coconut husk matrix and the hollow kapok fiber structure. These findings underscore the novelty of combining complementary agro-waste fibers into a high-performance aerogel and establish a scalable, low-cost route for transforming waste biomass into sustainable sorbents for large-scale marine oil spill remediation.