Biosorbents have been highlighted as an alternative method for the removal of contaminants from spills or leaks of oil and its derivatives, since they are biodegradable, are highly available, low-cost, and have a good sorption capacity. This research investigated the sorption capacity of Calotropis procera fiber in natura (CP) and thermally treated (150 °C and 200 °C) for crude oil removal and recovery. The oil sorption tests were carried out in a dry and water (layer) static systems. The assays revealed that CP fiber has excellent hydrophobic-oil properties and good crude oil sorption capacity, about 75 times its own weight (76.32 g/g). The results of the treated fibers, CPT150 and CPT200, showed oil sorption capacities (in 24 h) higher than CP, between 94.31–103.37 g/g and 124.60–180.95 g/g, respectively. The results from sample CPT200 showed that it can be an excellent biosorbent for the removal of crude oil and other derivatives due to its high hydrophobicity, great reuse/resorption capacity, and ability to retain oil within the fiber lumens. Thus, it can be applied in the recovery, cleaning, and removal of petroleum products and its derivatives from spills and leaks in the future.

Calotropis procera (CP) fiber is a natural and renewable material with great lumen and hydrophobic-oleophilic characteristics, providing it with a good oil absorption capacity. In order to increase the absorption efficiency of organic oils and solvents, CP fiber was treated with either 0.1 M NaOH (CPNaOH), 1% NaClO2 (CPNaClO2), or hydrothermal conditions (CPHT) in an effort to improve its ability to remove crude oil from leaks or spills. The fibers were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with field emission (SEM-FEG), and wettability for water and diesel. The fibers CPHT, CPNaOH, and CPNaClO2 showed excellent hydrophobic-oleophilic properties and good crude oil absorption capacity in water 99.2 g/g, 103.9 g/g, and 92.0 g/g. The absorption after 60 min for most fibers in dry systems or with a layer of oil floating on water exceeded 90% of its absorption capacity for the time of 1440 min. The CPNaOH after 6 runs absorbed 445.8 g of crude oil per gram of fiber. Based on the results, the treated fibers can be considered an alternative for the removal of oil from leaks and spills due to the high availability and excellent absorption property for various oils.

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Biosorbents have emerged as an alternative to remove organic contaminants because they are natural products with a high availability, low cost, biodegradability, and good sorption capacity. The Mandacaru (Cereus jamacaru DC) was investigated as sorbent of diesel, and compared with the Mandacaru modified with microemulsions. The sorbents were also submitted to a physycal-chemical characterization for FT-IR, TG/DTG, MEV and CHN-O. The granulometry range 500-150 µm of the Mandacaru particulate, this was the granulometry range chosen as the standard one, being used in the modification and sorption tests. The unclassified Mandacaru presented a medium sorption capacity of the diesel oil of 1.61 g g-1. Whereas the Mandacaru modified with a microemulsion comprised of direct micelles (oil/water) showed a remarkable increase in the sorption capacity of 80-111% (3,08 to 3,54 g g-1).

Lignocellulosic materials have been used as bioadsorbents for contaminants removal from industrial effluents due to their physical-chemical properties, renewable source, low-cost and efficiency that make them competitive to commercial activated carbon. The objective of this work is to develop an efficient and low cost bioadsorbent reusing the cashew nut shell (Anarcadium accidentale L), CNS, for the removal of metal ions (Cu2+ and Cr3+). The CNS was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), the point of zero charge (pHpzc) and the Boehm titration. The kinetics and adsorption equilibrium experiments were carried out in a monoelementary system, in batch runs at room temperature. The adsorption kinetics was evaluated by the mathematical models of pseudo first-order, pseudo second-order and intraparticle diffusion, while the adsorption isotherm was adjusted according to the Langmuir, Freundlich and Redlich-Peterson models. The removal percentage was 91% (Cu2+) and 96% (Cr3+) and adsorption kinetics was better adjusted to the pseudo second-order model, suggesting the predominance of chemisorption. The fit of the Langmuir isotherm was better for the experimental data of Cu2+ and Cr3+ ions, indicating adsorption in monolayers. It is concluded that the bioabsorbent produced from the cashew nut shell has a high potential for the removal of metals, in addition to being an abundant product in nature, is renewable and biodegradable and its reuse contributes to the reduction of environmental pollution, the production of waste and improves the local circular economy through the valorization of the byproduct.