Optimization of process variables using response surface methodology for tocopherol extraction from roselle seed oil by supercritical carbon dioxide

Hibiscus sabdariffa L. (Roselle) seeds are rich in proteins, carbohydrates and unsaturated fatty acids, and are a good source of minerals and antioxidants. Supercritical carbon dioxide (SC-CO2) extraction was applied for extraction of oil from Roselle seed at temperatures of 40 °C to 80 °C and pressures of 20 MPa to 30 MPa. The effects of temperature and pressure on the extraction yield and solubility of oil were determined. Process optimization was carried out using response surface methodology (RSM). A particle size of 300 μm, SC-CO2 flow rate of 5 mL/min and extraction time of 180 min were held constant throughout this study. The overall oil yield increased as pressure and temperature was increased, while a reverse effect was observed at higher temperatures. The optimum extraction conditions for Roselle seed oil corresponded to a pressure of 30 MPa and temperature of 40 °C. According to the analysis of variance (ANOVA), the coefficient of determination R2 for oil yield and gamma tocopherol concentration were 0.9723 and 0.9754, respectively, indicating a good correlation and agreement between the experimental and predicted values

Reverse micelle extraction of antibiotics using an eco-friendly Sophorolipids biosurfactant

Reverse micelles extraction of erythromycin and amoxicillin were carried out using the novel Sophorolipids biosurfactant. By replacing commonly used chemical surfactants with biosurfactant, reverse micelle extraction can be further improved in terms of environmental friendliness and sustainability. A central composite experimental design was used to investigate the effects of solution pH, KCl concentration, and sophorolipids concentration on the reverse micelle extraction of antibiotics. The most significant factor identified during the reverse micelle extraction of both antibiotics is the pH of aqueous solutions. Best forward extraction performance for erythromycin was found at feed phase pH of approximately 8.0 with low KCl and sophorolipids concentrations. Optimum recovery of erythromycin was obtained at stripping phase pH around 10.0 and with low KCl concentration. On the other hand, best forward extraction performance for amoxicillin was found at feed phase pH around 3.5 with low KCl concentration and high sophorolipids concentration. Optimum recovery of erythromycin was obtained at stripping phase pH around 6.0 with low KCl concentration. Both erythromycin and amoxicillin were found to be very sensitive toaqueous phase pH and can be easily degraded outside of their stable pH ranges

Preparation of iron oxide nanocatalysts and application in the liquid phase oxidation of benzene

A series of iron oxide nanocatalysts were prepared using an ultrasonically assisted co-precipitation technique. Molybdenum promoted Fe3O4 and Fe2O3 were prepared from the original materials by wet impregnation using a solution of ammonium molybdate. The catalysts were tested in the liquid phase oxidation of benzene at atmospheric pressure and at 60°C using molecular oxygen. Phenol yields between 7% and 14.5% were obtained. The major products were pyrogallol and catechol