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Oil spills have caused significant environmental problems, placing the requirement of efficient and low-cost materials for the decontamination and cleanup. In attempts to answer for this requirement, in this work superhydrophobic nanocomposite sponges were developed, based on readily available and low-cost polyurethane (PU) sponges due to robustness and macro-porous structure, which were dip coated by the zeolitic imidazolate framework (ZIF8) metalorganic framework as low density crystal and tunable microporous structure and polydimethyl siloxane (PDMS) to increase the hydrophobicity. The obtained composite sponges presented a nice porous structure, the surface of which was uniformly covered with the crystals of ZIF8 and PDMS. Therefore, the superhydrophobicity was obtained to show the water contact angle as high as 156o, which was prone to be wet by oils. The high-water contact angle was preserved even in the acidic and basic environment due to the physico-chemical modification of the PU surface that provided improved chemical resistance and increased hydrophobicity. Accordingly, the nanocomposite sponges absorbed low water amount (0.5 g/g) and high oil amount (58 g/g) and presented an excellent oil/water separation performance. The synergistically combined materials along with the excellent surface and porous properties were accounted for the performance attained.

The performance of gas industries is extensively function of gas properties such as gas density. Due to this importance in the present work, a novel grid partitioning based fuzzy inference ...

Regarding the indispensable risk management of hazardous accidental releases through oil production and its transportation, spongy absorbents have recently gained wide attention as one of the most effective oil spill cleanup techniques to accumulate the oil in the bulk medium and effectively remove the oil pollution. In this study, a superhydrophobic/superoleophilic novel spongy absorbent has been developed. It is composed of a polyurethane sponge coated with zinc stearate (which is first ever introduced as a superhydrophobic material) and phenol-formaldehyde resin by the dip-coating method, providing both the necessary roughness and chemical hydrophobicity features simultaneously. Characterization by FTIR, SEM, and EDX mapping results showed that the zinc stearate was uniformly dip-coated throughout the polyurethane to roughen the surface; this occurred as the result of the strong chelating bonds formed between the carboxylates and Zn atoms on the surface. However, no significant change happened after immersing this product in acidic and basic solutions. The water contact angle measurements revealed that the static contact angle increased from 70° ± 2 on the unmodified substrate to 175° ± 2 for the zinc stearate-coated sponge. Interestingly, the dynamic water contact angle was also lower than 10°, sliding ~8°, and shedding ~7°, strongly confirming the excellent superhydrophobicity of the fabricated zinc stearate-coated polyurethane. Finally, the absorption rate and capacity of the unmodified and modified sponges using two different polyurethane densities for treating various oils and solvents demonstrated that the coated polyurethane spongy absorbent was capable of absorbing a wide range of oils and organic solvents in a time range of 30–50 ms and oil capacity range of 6–81 times their weight, depending on the different sponge densities.

Summary Carbone dioxide injection is one of the most frequently used enhanced oil recovery methods. However, injection of CO2 in heavy oil reservoirs with high percentage of asphaltene usually results in asphaltene precipitation in porous media that causes many problems, including reduction in the oil production. One possible method to reduce asphaltene precipitation is the injection of nano-fluids into the oil reservoirs. Carbone dioxide gas that is saturated with nanoparticles can be used to control asphaltene precipitation issue. In this study, vanishing interfacial tension technique was used to investigate the possibility of diminishing asphaltene precipitation by nano-particles. The results of this study shows that in solutions containing asphaltene, an increase in pressure causes the interfacial tension between oil and CO2 gas to decrease linearly with two different slopes at low and high pressure ranges. Nevertheless, addition of iron oxide nanoparticles to the oil solution can reduce the interfacial tension at higher pressures and control asphaltene precipitation. Moreover, it was found that the onset of asphaltene precipitation could be predicted by plotting the Bond number versus pressure.