# Modified Kapok Fibers (_Ceiba pentandra_ ([PERSON]) for Oil Spill Remediation
###### Abstract
In recent years, these fibers have shown their remarkable oil sorption capacity, from plants originating in different parts of the globe, such as fibers from Asia, with sorption varying from 12.53 to 38.1 g/g [22; 23], up to the highest values found with South American fibers, at 58 g/g [21]. [PERSON] and co-workers (2012) treated kapok fibers, aiming to promote structural modifications that would enhance their lipophilicity [22]. The authors observed that a 50 min contact time with an acidic, alkaline, or organic solvent was ideal, pointing out that above this threshold, the oil affinity starts to decrease due to functional and morphological degradation. The same work also cited that there is a reduction in the lipophilic surface wax and an increase in roughness when the fibers are kept in contact with HCl, NaOH, CHCl\({}_{3}\), and NaClO\({}_{2}\), implying that the structural effect might be more relevant to sorption than the wax. [PERSON] and [PERSON] (2013) tested the acetylation of fibers and reported a reduction in crystallinity and a considerable change in the surface composition for the treated materials, with an increase in the O/C ratio and grooves on the walls, demonstrated through SEM, and a boost in the sorption capacity for fibers treated with low concentrations of acetic anhydride [24]. It is noteworthy that rugosity shows up frequently as a relevant property regarding particle adhesion, according to the work of [PERSON] et al. (2016), where this parameter directly interferes with floatation systems, assuring the higher efficiency of adhesion to air bubbles [25]. Several works suggest that a material's surface roughness is a parameter of proportionality to its performance as an oil sorbent, because an increment in morphological disposition randomness leads to the expansion of the surface area, including the presence of cavities and support structures, in addition to augmenting friction, which reduces oil outflow [26; 27], especially after the sorbent has been applied and is being transported to a destination for oil recovery or final disposal. Notwithstanding, to this day, the influence of morphological parameters of natural materials has yet to be determined to assert precise correlations between sorption and fiber diameter and roughness. Furthermore, since the sorption process is volumetric and not necessarily superficial, the extent to which surface care treatments will improve the volume of oil removed from an environment, or whether these treatments would become economically unviable in the production of kapok-based sorbents, is in question. Therefore, this work employed thermal, acid, and alkali activation treatments to kapok fibers from the Brazilian coast, in order to evaluate the effect of modifications on the surface roughness for the sorptive behavior of the biomass towards diesel oil. The materials were characterized through Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and Fourier Transform Infrared spectroscopy (FTIR) to assess the effects that the functionalization and the microstructure have in oil capture and adhesion. As a result, the manuscript intends to clarify the effects of surface treatments directed at biomasses intended for applications in oil spill remediation scenarios, with the expectation of suggesting or declining the viability of these activations.