Analysis of Microwave Heating Process for Demulsification of Water-in-Crude Oil Emulsions

In this investigation, the process of microwave heating technology was evaluated to measure the effect of some important parameters such as dielectric properties (έ and ɛʺ), rate of temperature increase (dT/dt), volume rate of heat generation (Qmw), wavelength (λ) and penetration depth (Dp) during the microwave irradiation on crude oil emulsions. Two types of Malaysian crude oil mixed together at a volume ratio of 50-50% and applied for further investigations. In order to ensure the efficiency of the process, the improvement of existing techniques and the development of new technology different ratios of water and oil were utilized to prepare the emulsions of water-in-crude oil (W/O). The emulsion samples were heated under 360 watt and 540 watt for 3 to 5 minutes. The findings of the microwave heating demulsification showed that higher microwave power (540 watt) along with the radiation time (5 min) were not much effective for water separation. This is because of the over boiling of the samples. Consequently, for microwave heating demulsification the best water separation efficiency was achieved at 3 (minutes), 360 (watt). Based on the result of microwave parameter’s calculations, it was found that parameters such as; dT/dt, Qmw, έ and ɛʺ, were inversely proportional to the radiation time. However, parameters such as λ and Dp were directly proportional to the time of the radiation

Optimization of saponins, phenolics, and antioxidants extracted from fenugreek seeds using microwave-assisted extraction and response surface methodology as an optimizing tool

Fenugreek is a multiregional plant mostly found in Asia, the Middle East, and some European countries. Thus, this study aimed to optimize the microwave-assisted extraction (MAE) process parameters such as irradiation time (2–4 min), ethanol concentration (40–80%), microwave power (500–700 W), solid-to-liquid ratio (1:8–1:12 g/mL), and a fixed extraction temperature (70 °C) for fenugreek seed powder. Response surface methodology (RSM) was applied to optimize MAE process parameters to achieve optimal total saponin content (TSC), total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) antioxidant capacities of fenugreek seed extract. The levels of independent variables were first evaluated using one-factor-at-one-time method, after which the suitable levels (−1, 0, and +1) were selected for the optimization process. The optimal conditions of MAE parameters were found to be 2.84 min, 572.50 W, 63.68%, and 0.09 g/mL. Based on the suggested optimum conditions, the obtained responses were 195.89 ± 1.07 (mg diosgenin equivalent/g d.w.), 81.85 ± 0.61 (mg gallic acid equivalent/g d.w.), 92.86 ± 0.56%, and 95.85 ± 0.81%. Analysis of variance revealed that all the responses including TSC, TPC, DPPH, and ABTS antioxidant capacities were significantly influenced (P < 0.05) by irradiation time, solvent concentration, microwave oven power, and feed-to-solvent ratio. Hence, the results obtained from liquid chromatography–quadrupole–time-of-flight mass spectrometry indicated the presence of steroid saponins, triterpenoid saponins, phenolics, and other natural antioxidants

Iridoids of fenugreek (Trigonella-foenum-graecum L.) seed extract detected via LC-QTOF-MS analysis

Fenugreek seed is a traditional medicinal plant with a wide biological activity. In this study, iridoids (Asperulosidic acid (1), 7-O-Methylmorroniside (2), Gentiopicroside (3), Rehmannioside A (4), Loganic acid-6′-O-β-Dglucoside (5), Sweroside (6), Penstemoside (7), 6′-O-β-D-Glucosyl Gentiopicroside (8), Oleuropein (9)) in optimized microwave-assisted extract of fenugreek seed were detected for the first time. The identification of iridoid compounds was carried out by liquid chromatography quadrupole time-of-flight mass spectrometry coupled with electrospray ionization (LC-QTOF-MS-ESI) in positive ion modes and Fourier Transform Infrared Spectroscopy (FTIR) analysis. More than 400 compounds were detected via LC-QTOF-MS, while among them only 9 were iridoids. The presence of iridoid compounds was also confirmed with FTIR analysis. In positive ion mode, iridoids with formic acid as mobile phase associated in formation of three adducts [+ H, + Na + K]. However, in the case of negative ion no iridoid compound was observed in the extract

A History of Alcohol Dependence Increases the Incidence and Severity of Postoperative Cognitive Dysfunction in Cardiac Surgical Patients

Postoperative cognitive dysfunction (POCD) commonly occurs after cardiac surgery. We tested the hypothesis that a history of alcohol dependence is associated with an increased incidence and severity of POCD in male patients undergoing cardiac surgery using cardiopulmonary bypass. Recent verbal and nonverbal memory and executive functions were assessed before and one week after surgery in patients with or without a history of alcohol dependence. Cognitive function was significantly reduced after cardiac surgery in patients with versus without a history of alcohol dependence. The results suggest that a history of alcohol dependence increases the incidence and severity of POCD after cardiac surgery

Extraction, characterization and antioxidant activity of fenugreek (Trigonella-Foenum Graecum) seed oil

Fenugreek (Trigonella-Foenum Graecum) is known as one of the traditional and most promising medicinal herbs belongs to the leguminous family. The seeds of fenugreek have been extensively studied for the treatment of inflammation, cancer and diabetes. In this study, fenugreek seed oil was extracted and evaluated for its chemical compositions and bonding through gas chromatography coupled to mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FT-IR) analysis, respectively. The antioxidant activity against 2,2-diphenyl-picrylhydrazyl (DPPH) and 2,2′-Azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS+•) radicals, total phenolic content (TPC) and total flavonoid content (TFC) of the oil were also studied. The capacity of antioxidants detected by ABTS was stronger than that by DPPH. A total number of 23 chemical compounds were detected and identified in fenugreek seed oil comprising of 99% of the total oil through GC-MS analysis. The major compounds of the extracted oil were linoleic acid (54.13%), palmitic acid (16.21%), pinene (4.56%), 4-Pentyl-1-(4-propylcyclohexyl)-1-cyclohexene (3.87%) and linoleic acid methyl ester (3.19%). FTIR analysis confirmed the presence of carboxyl group in the oil which were more dominated by unsaturated essential fatty acids. Moreover, the oil of fenugreek seed indicated a strong antioxidant radical scavenging activity against both DPPH and ABTS assays with an IC50 of 172.6 ± 3.1 and 161.3 ± 2.21, respectively. The TPC and TFC of the oil were 38.97 ± 0.34 mg GAE/g. oil and 14.417 ± 0.23 mg QE/g.oil. Thus, this study suggests that the fenugreek seed oil could be used for pharmaceutical purposes

The Influence of Process Parameters on Stability Of Water-In-Crude Oil Emulsion Stabilized by Span 80

There is a wide range of scientific literature related to emulsion stability, most of them dealt with water-in-oil (W/O) or oil-in-water (O/W) type. The present work is aimed to investigate the stability mechanisms of water-in-crude oil emulsion stabilized by a non-ionic emulsifier (Span 80). The blending of (50-50 vol. %) heavy and light crude oil was first characterized in terms of physico-chemical properties. The emulsion was stabilized by (1.5 and 2.5 vol. %) emulsifier at different water: oil ratio of (20-80 vol. %) and (40-60 vol. %). According to the result of microscopy images, the steric stability was obtained in low water volume fraction content (20%), with the smaller droplet sizes and at higher surfactant concentration (2.5%). The emulsions stabilized with Span 80 obtained a visually stable emulsion in both concentrations of emulsifier and volume fractions of dispersed phase (water) in a period of one week,and there was no water separation was observed in this period. To determine the dynamic viscosity rate, the temperature was varied from 30 ºC to 90 ºC and shear rate from (17 to 85)1/sec respectively. Moreover, the emulsion with the higher water volume fraction (40%) and emulsifier concentration of 2.5 % indicated higher dynamic viscosity.However, in all types of the samples, the dynamic viscosity decreased by increasing the shear rate. The results obtained in this study have exposed the capability of the chosen emulsifier as another promising method for stabilizing w/o emulsions. Further works are, nevertheless, required to provide deeper understanding of the mechanisms involved to facilitate the development of an optimum system applicable to the industr

Rheology and Stability Mechanism of Water-in-crude Oil Emulsions Stabilized by Span 83

Water-in-crude oil (W/O) emulsions are found in many industries such as cosmetic, pharmaceutical, and petroleum. The study was aimed to investigate the rheological properties and the stability mechanism of W/O emulsions at different water to oil ratios of (20-80 vol.%) and (40-60 vol.%). The emulsions were stabilized by a non-ionic surfactant (Span 83) at concentrations of 1.5-2.5 vol.%. The heavy and light crude oils were mixed at 50-50 vol.% and characterized in terms of physical and chemical properties. From the results, it was found that the emulsion with higher water volume fraction obtained more viscosity with larger droplet sizes which present low stability. As well as, the higher viscosity was obtained in emulsion with higher emulsifier concentration (2.5 vol.%). However, 20-80 % W/O emulsion and emulsions stabilized with 2.5 % Span 83 produced more stable emulsions as observed through the optical microscopy images. In order to determine the dynamic viscosity, different temperatures from (30 to 90 ºC) and spindle rotational speeds from (50 to 250 rpm) were used. Furthermore, all types of prepared emulsions were visually stable over a period of more than one week, where no water separation was observed during this period, besides; they exhibited a non- Newtonian shear thinning fluid behavior

Demulsification of Water-in-Crude Oil Emulsion via Conventional Heating and Microwave Heating Technology in their Optimum Conditions

A serious problem during the production and refinery process of crude oil is the existence of emulsified water in the crude oil. From the economic and environmental points of view, water must be removed from the crude oil before going for further processing. In the last two decades, several demulsification techniques have been applied by many researchers. Since, the best method is based on the best water separation efficiency. Therefore, a comparative study between microwave heating and conventional heating demulsification in their optimum conditions has been carried out. Both methods were performed with the assistance of chemical demulsifier. Through the experimental results, it was found that comparing to the conventional heating; microwave dielectric heating earned the best separation efficiency (100 %) in a short time. The optimum condition in microwave dielectric heating was irradiation time (3 minutes), microwave power (360 watt), and 2.50 vol. % demulsifier concentration. However, in conventional heating using “hotplate” the highest separation efficiency (96 %) was obtained at 160 ºC, and heating time 5 minutes

Microwave-assisted extraction of saponin, phenolic and flavonoid compounds from Trigonella foenum-graecum seed based on two level factorial design

Fenugreek (Trigonella-foenum graecum) is a tropical plant with medicinal properties which is traditionally known since the ancient time. In this research, various microwave-assisted extraction (MAE) related parameters such as extraction time (2–12 min), ethanol concentration (20–100%), microwave power (300–700 W), ratio of feed-to-solvent (1:8-1:16 g/mL) and extraction temperature (40–80 °C) were evaluated using experimental method of one-factor-at-a-time (OFAT). The screening of extraction parameters was then evaluated using two-level factorial design under Design-Expert to find out the significant parameters in terms of obtaining high extraction yield, total saponin, phenolic and flavonoid contents in fenugreek seed. The results of OFAT revealed that the maximum yields of recovery were achieved at microwave parameters of 3 min irradiation time, microwave power 600 W, 60% solvent concentration, 1:10 g/mL of feed-to-solvent ratio and 70 °C temperature. The screening process using two level factorial design (TLFD) also indicated that solvent concentration, time of irradiation, microwave power and ratio of feed-to-solvent were the significant parameters affecting the recovery yields of total saponin, phenolic and flavonoid contents where (p  0.05). The extract was also evaluated for its chemical composition using GC–MS analysis

Biosurfactants as promising multifunctional agent: A mini review

Biosurfactants are derived from plants and microorganisms such as fungi, yeast, and bacteria. Biosurfactants are also called natural surfactants which are amphiphilic biological compounds comprised of both hydrophilic and hydrophobic moieties. The environmental concerns about the effect of toxic and conventional surfactants have increased the demand for renewable and biodegradable surfactants with low toxicity and other useful effects. Therefore, the application of biosurfactants has gained much attention in different industries mainly in petroleum, food, cosmetic and pharmaceutical products. This review summarizes the utilization of biosurfactants as emulsifying, wetting, foaming and antimicrobial agents in various industrial processes along with their promising availability and ensuring environmental quality