Rehab F.M. Ali

Physico-chemical properties of biodiesel manufactured from waste frying oil using domestic adsorbents

Abstract We have evaluated the efficiency of sugar cane bagasse ash (SCBA), date palm seed carbon (DPSC), and rice husk ash (RHA) as natural adsorbents and compared them with the synthetic adsorbent Magnesol XL for improving the quality of waste frying oil (WFO) and for the impact on the physicochemical properties of the obtained biodiesel. We measured moisture content, refractive index (RI), density, acid value (AV), iodine value (IV), peroxide value (PV), and saponification value (SV), as well as fatty acid profile. Purification treatments with various levels of adsorbents caused significant (P ≤ 0.05) decreases in free fatty acids (FFAs), PVs, and IVs. The highest yields (86.45 and 87.80%) were observed for biodiesel samples produced from WFO treated with 2% Magnesol and 3% of RHA, respectively, followed by samples treated with 2 and 3% of DPSC or RHA. Pre-treatments caused a significant decrease in the content of C 18:2 linoleic acids, consistent with a significant increase in the content of monounsaturated and saturated fatty acids (MUFA) in the treated samples. The highest oxidation value (COX) (1.30) was observed for biodiesel samples produced from WFO without purification treatments. However, the lowest values (0.44–0.73) were observed for biodiesel samples produced from WFO treated with different levels of adsorbents. Our results indicate that pre-treatments with different levels of adsorbents regenerated the quality of WFO and improved the quality of the obtained biodiesel.

Hypolipidemic and Hypocholesterolemic Effect of Roselle (Hibiscus sabdariffa L.) Seeds Oil in Experimental Male Rats

The current investigation aimed to evaluate the influence of roselle seeds oil (RSO), coconut oil (CNO) and binary mixture of them on serum lipids of experimental rats. Fatty acid composition of native and blended oils was determined. Thirty five male Albino rats (145- 160 g) were used throughout this study. The rats were fed AIN-93G diet containing 10% fat from CNO, RSO, B1 (25%RSO+ 75 %CNO), B2 (50 %RSO+ 50 %CNO or B3 (75 %RSO+ 25 % CNO) for eight weeks. Blood samples were collected at the beginning, every two weeks during the experiment, and at the end of the experiment. At the time of sacrifice, organs weights in relation to their body weights were immediately recorded. Substitution of 25, 50 and 75 % of CNO with equal amounts of RSO reduced saturated fatty acids by 16.04, 32.58 and 48.77 %, respectively in blended oils. The content of linoleic (C18:2) increased from not detected level in CNO to 9.81, 19.67 and 29.48 % in CNO blended with 25, 50 and 75 % of RSO, respectively. The relative liver weights of rats fed CNO was significantly higher than that of those fed RSO and blended oils. Mixing CNO with various levels of RSO attenuates the adverse effect in the relative liver weights which caused by CNO administration. At the end of the experiment, blinding coconut oil with 25, 50 and 75 % of roselle oil inhibited the elevation in total cholesterol by 9.69, 28.16 and 36.16 %, respectively compared to CNO rats. Rats fed diet containing CNO for 8 weeks had significantly the highest content (126.49 mg/dl) of low-density lipoprotein cholesterol, while those fed 100 % RSO (as a source of lipids) had the lowest concentration of LDL-C (64.32 mg/dL). Atherogenic index (AI) values of rats submitted B1, B2 and B3 were about 1.12, 1.23 and 1.28 times as low as those of rats fed CNO diet, respectively. The results of this study indicate that roselle seeds oil (RSO) reduces hyperlipidemia and hypercholesterolemia in rats fed diet rich in saturated fatty acids.

Regeneration of Used Frying Palm Oil with Coffee Silverskin (CS), CS Ash (CSA) and Nanoparticles of CS (NCS)

The present investigation aimed to evaluate the efficiency of coffee silverskin (CS), CS ash (CSA) and nanoparticles of CS (NCS) in regeneration the quality of used frying palm oil. The adsorbents were mixed individually with used frying palm oil at level 4% (w/v) for 60 min. The properties of CS, CSA and NCS adsorbents were studied using (SEM) scanning electron microscopy technique. Some of physico-chemical characteristics of used frying palm oil (UFPO) and UFPO treated with adsorbents were determined. The results showed that the CS ash particles composed of irregular spherical and semispherical grains with deep cavities. The size of particles of CS ash ranged in diameter from 1.1 to 1.7 µm. The morphology of NCS consisted of cluster-type spherical nanoparticles and flakes. The particle size of NCS varies from 0.9 to 1.7 µm. Purification treatments caused marked (p<0.05) increases in the quality parameters of treated oil compared to untreated oil. The treatment of UFPO with 4% of adsorbents caused significant reductions in the content of free fatty acids ranged from 51.2 to 65.0%. The lowest level of peroxide (2.1 meq/kg) was recorded for UFPO treated with 4% of NCS. The highest reductions (72.8; 70.0%) in p-anisidine value were observed in UFPO treated with 4% of CSA and NCS, respectively. Treatment of UFPO with 4% of CS, CSA and NCS significantly lowered the polar content from 13.9% to 6.3, 4.8 and 3.9%, respectively. The results also indicate that CSA and NCS have nearly the same adsorption efficiency in lowering polymer content of UFPO. Filtration treatment of UFPO with 4% of CS, CSA and NCS markedly lowered the viscosity and colour values of treated UFPO.

Stabilization of Neem Oil Biodiesel with Corn Silk Extract during Long-term Storage

The current study aimed to evaluate the antioxidant efficiency of different extracts of corn silk. In addition, the impact of corn silk extract on oxidative stability of neem biodiesel during storage was studied. The highest phenolics, DPPH radical scavenging and reducing power activities were recorded for methanol-water extract. The longest oxidation stability (10 h) was observed for biodiesel samples blended with 1000 ppm of corn silk extract (CSE). At the end of storage period the induction time of biodiesel samples mixed with 1000 ppm of CSE or butylated hydroxytoluene (BHT) were about 6.72 and 5.63 times as high as in biodiesel samples without antioxidants. Biodiesel samples blended with 1000 ppm of CSE had the lowest acidity at the end of storage period. Peroxide value of biodiesel samples containing 1000 ppm of CSE was about 4.28 times as low as in control sample without antioxidants.