Evaluating the Characteristics and Performance of Pristine and Modified Kapok Fibers as Marine Oil Sorbents

Kapok fibers exhibit high hydrophobicity due to the presence of cutin on its surface. It also has oleophilic properties, making it a suitable sorbent for oil spill cleanup applications. To further improve its sorption capacity for industrial oils, e.g. bunker oil, modification of kapok fibers via in-situ deposition of calcium stearate was conducted. Two solvents (ethanol and ethyl acetate based on solubility) were considered in the preparation, while the efficiency of post-washing in removing excess coating powder was also determined. Results showed using ethanol and ethyl acetate during modification enhanced the surface roughness and hydrophobicity of the kapok fibers. Then again, ethanol is recommended considering its chemical properties, environmental and health hazards, and economic factors. An increased in water contact angle from 136° to 143° was observed. FTIR spectroscopy confirmed that the calcium stearate coating on the modified kapok surfaces remained even after post-washing. Initial results for the BFO sorption capacity of raw and modified fibers were 43.61 g/g and 43.43 g/g, respectively. Although the performance of both sorbents were not significantly different ( p -value = 0.45), the coating of fibers can potentially mitigate its storage and transportation concerns including spoilage and flammability. The results of this study provide a basis for future research on the development of kapok-based sorbents for effective marine oil spill remediation.