Saponins are the main group of phytogenic biosurfactants extracted from plants. One of the significant applications of these compounds is upgrading and viscosity reduction of heavy crude oil water in oil (W/O) emulsions. In this research, use of saponin extracted from Glycyrrhiza glabra was investigated for viscosity reduction of heavy crude oil and upgrading its API properties. The extracted saponin was characterized using Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. Phase behavior analysis demonstrated a reduction in initial viscosity and improved API gravity of the heavy oil from 2350 mPa·s and 19 to 900 mPa·s and 27, respectively. In addition, the emulsification index (E24) was found to be 98 % at a saponin concentration of 8 % w/v. It was observed that the emulsions were stable in the pH range of 5.5–13, temperature from 30 to 80 °C and salinity up to 6 % w/v of NaCl solution. Average diameter of W/O droplets evaluated by dynamic light scattering (DLS) were in the range of 10–15 µm. The results obtained from the present research revealed that the extracted saponin improved the physical characteristics of heavy crude oil. We propose the use of saponin as a potential alternative to conventional emulsifiers for upgrading heavy crude oil in petroleum industry.
The change in the properties of low-density polyethylene after adding starch, oxo-material, polylactic acid, and their mixture was studied. Different amounts of the additives were added, and films were prepared by using a twin-screw extruder at 150-225 C. By Minitab software, the optimum percentages of the additives were selected. The films were kept under different environmentalconditions including "open atmosphere," "buried underground," and "buried underground with regular daily irrigation" for 6 months. The degradability, tensile strength, elongation at breaking point, and dart impact were measured. Thermogravimetric analysis and FTIR spectrum changes were used to monitor changes. SEM images illustrated that the starch changed the morphology significantly, while other additives did not show remarkable effects. Mechanical and chemical properties changed significantly when starch was added. The highest changes were recorded for the sample with three additives, which was showing the high efficiency of the film decomposition. The highest amount of chemical changes was recorded for the same film. After 6 months, the lowest crystallinity was recorded by DSC and XRD for the same sample. Different environmental conditions showed different effects on the films mechanical properties. However, chemical properties of the films, excluding the film with starch, did not change significantly.
Today, the tendency to use of natural preservatives to increase food security has expanded. In the present study, antibacterial effects of Areca Nut fruit extracts were evaluated against Staphylococcus aureus, Escherichia coli, Salmonella enterica, and Enterobacter aerogenes bacteria using agar disc diffusion technique. Methanol, ethanol, and water were used as solvents for extraction by maceration method, and extracts were analyzed by GC-MS. The antibacterial activity was evaluated using microtiter broth dilution method to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Results revealed that all ATCC strains were significantly inhibited by ethanolic and methanolic extracts. Escherichia coli produced a significantly larger zone of inhibition for Gentamicin (
35
±
0.65
mm
) and Penicillin (
25
mm
±
0.56
), while Enterobacter aerogenes produced smaller zone of inhibition for Gentamicin (20 ± 0.87 mm) and Penicillin (
15
±
0.87
mm
). Also, methanolic extract had considerable antibacterial activity with MIC value of 1.56 mg/mL against Escherichia coli. All of extracts were used to evaluate antibacterial effects in prepared cake, and as a result, all pathogenies were the most sensitive by methanolic extract in 100 mg/L of concentration except Escherichia coli that were more sensitive by ethanolic extract. In conclusion, the Areca Nut fruit extracts may be used as a natural preservative in food industries. Future studies should focus on the effect of Areca Nut fruit extracts in bakery and drinking industries.
In this study synergistic effect of the biosurfactants saponin and rhamnolipid on the removal of the heavy metals such as vanadium, nickel and chromium from contaminated soil was investigated. Washing solutions were prepared by using different concentrations of two biosurfactants. In this work, the optimum HLB value of the extraction process of about 10.5 was obtained for the mixture of 62.5 % rhamnolipid and 37.5 % saponin. According to our results, at the optimal HLB value, a maximum removal was obtained for Ni of 87 %, Cr of 71 % and Va of 70 %. Our results also showed that the efficiency of heavy metals decreased with increasing the pH value of system. The optimum pH value of heavy metals removal was 5. According to the results of this research saponin and rhamnolipid have the synergistic effect on the heavy metals removal and it seems to be a good alternative to chemical surfactants for environmental applications.
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