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).

Conventional treatment of drill cuttings, as drying and thermal desorption, is failing to meet environmental and economic standards; therefore, new alternatives for the treatment of this waste must be developed. The purpose of this study was to remove n-paraffin from drill cuttings using microemulsion systems (MES). The extraction percentage (%) of n-paraffin was quantified by gas chromatography with a flame ionization detector. The optimization of extraction parameters showed that the extraction percentage (%) is directly proportional to the stirring speed and contact time and inversely proportional to the HLB of the surfactant used in the microemulsion system. Results for MES using Alkonat ® L90 and Renex ® 95 were similar, but Alkonat ® L90 was chosen as the best system considering the environmental issue. The MES/cuttings ratio did not influence the percentage of n-paraffin extracted, reaching 55.03% and 56.32% for the ratios of 0.5 and 2.0, respectively. The reuse of MES in multiple extractions showed that MES can be reused in up to two extractions, obtaining up to 86% extraction. The optimal parameters for Alkonat ® L90 microemulsion systems were MES/cuttings ratio of 1.0, stirring speed of 132 strokes, and contact time of 80 min, achieving 86.27% extraction. Results obtained in this study may help to better understand n-paraffin removal from drill cuttings by MES, considering the future use of this technology in the design of an industrial treatment plant for both onshore and offshore operations.

Biodiesel is considered a clean and renewable energy source, however it is important to know the environmental impacts caused by the water-soluble fraction (WSF) of this fuel, in the event of a spill. The objective of this research was to evaluate the seawater-soluble fraction of biodiesel (B100) compared to diesel (S500). A factorial design was used to carry out the experiments and evaluate the WSF's, varying the type of fuel and the contact time between oil and water (O/W) from 1h to 24h. The mortality rate (%) of Mysidopsis juniae and the concentration of total hydrocarbons (TPH) were used as response variables. The results obtained demonstrate that diesel showed greater toxicity, with an average mortality rate of 98.4 % and TPH concentration of 475.8 µg/L in the water-soluble fraction. On the other hand, biodiesel did not present significant toxicity in the exposure of organisms, even after 24 hours of contact, but it can still cause risks in cases of spillage (average mortality rate of 15.0%). The empirical models obtained using the experimental design methodology were able to satisfactorily estimate the TPH concentrations and the mortality rate in the WSF, with precision above 99%, with correlation coefficients (R²) of 0.9963 and 0.9970. Pure biodiesel, due to its low lethality of organisms, biodegradable and from a renewable source, is an ecologically favorable proposal as a fuel, causing less impacts in cases of spillage in seawater.

O derramamento de petróleo e seus derivados na água e no solo tem sido um desafio no mundo há décadas, devido à alta toxicidade e mobilidade dos hidrocarbonetos. Um dos métodos mais eficiente para minimizar esse tipo de contaminação é o uso dos processos de sorção. Atualmente, os sorventes sintéticos são os mais utilizados em derramamento de óleos, devido às suas ótimas propriedades oleofílicas e hidrofóbicas. Entretanto, devido seus custos elevados diversas pesquisas vêm buscando sorventes alternativos. Os biosorventes vêm se destacando como método alternativo na remoção de contaminantes orgânicos, pois além de serem biodegradáveis, apresentam alta disponibilidade natural, baixo custo, e uma boa capacidade de sorção. O objetivo desta pesquisa foi hidrofobizar o Madacaru (Cereus jamacaru DC.) com a cera de Carnaúba para uso como material sorvente na remoção de diesel em casos de derramamento. O material foi caracterizado pelas técnicas FTIR, TG/DTG, DSC, MEV, Molhabilidade/Ângulo de contato. A hidrofobização aumentou significativamente a afinidade do material por óleo com um ângulo de contato com a água de 94º; as micrografias e FTIR confirmaram que as superfícies do Mandacaru foram cobertas por cera de carnaúba, e os resultados de sorção para diesel foram satisfatórios sem diminuição da capacidade de sorção pela hidrofobização (1,65±0,01 g/g).

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