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Chitosan films were used to remove heavy oil from connate water, deionized water, and seawater. In this research, chitosan-starch films were modified with natural extracts from cranberry, blueberry, beetroot, pomegranate, oregano, pitaya, and grape. These biodegradable, low-cost, eco-friendly materials show an important oil sorption capacity from different water conditions. It was observed that the sorption capacity has a clear correlation with the extract type, quantity, and water pH. In order to understand the physical and chemical properties of the films, they were analyzed according to their apparent density, water content, solubility, and swelling degree by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), gas chromatography-mass spectroscopy (GC-MS), and the determination of surface area using the Brunauer Emmett Teller (BET) method. The results indicate that chitosan-starch films modified with natural extracts can be successfully applied for environmental issues such as oil spill remedy.

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The most complex components in heavy crude oils tend to form aggregates that constitute the dispersed phase in these fluids, showing the high viscosity values that characterize them. Water-in-oil (W/O) emulsions are affected by the presence and concentration of this phase in crude oil. In this paper, a theoretical study based on computational chemistry was carried out to determine the molecular interaction energies between paraffin-asphaltenes-water and four surfactant molecules to predict their effect in W/O emulsions and the theoretical influence on the pressure drop behavior for fluids that move through porous media. The mathematical model determined a typical behavior of the fluid when the parameters of the system are changed (pore size, particle size, dispersed phase fraction in the fluid, and stratified fluid) and the viscosity model determined that two of the surfactant molecules are suitable for applications in the destabilization of W/O emulsions. Therefore, an experimental study must be set to determine the feasibility of the methodology and mathematical model displayed in this work.

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Purpose In recent years, the use of earth as a material applied to construction has been adapted as an attractive alternative to modern concepts. The earth construction technique takes advantage of regional natural resources, among which are earth bricks. The purpose of this paper is to analyze the effect of the addition of coconut fibers and aloe vera on the mechanical properties of compressed earth blocks (CEB). Design/methodology/approach CEBs were manufactured from silty and clay soil (Altamira, Tamaulipas, Mexico) with biodegradable stabilizers of aloe vera and short coconut mesocarp fibers, which were compared with the conventional mixture with lime as stabilizer. The samples were subjected to compression tests (Mexican Standard NMX-C-404-ONNCC3-205), flexion (NMX-C083-ONNCCE.), abrasion (NTC-5324 3.4.3), water absorption (NMX-C-37-ONNCE-205), surface morphology and thermal properties (ASTM D5334-14). Findings It was found that the addition of coconut fibers has a 12% difference in flexural strength. The addition of 0.5% of coconut fibers decreases swelling by 2% with water and reduces the thermal conductivity of the material by 12%. Likewise, this mixture increases the abrasion resistance of CEB by 30%. When there is a pressure greater than 1,700 psi in the CEB, the addition of coconut fibers does increase the compressive strength of the material, showing a 34% improvement over the CEB without adding coconut fibers. Originality/value The authors show a new sustainable CEB production with aloe vera and coconut fiber that is possible for self-production with better mechanical properties than others, commonly produced in Mexico.