Modification of thermal and oxidative properties of biodiesel produced from vegetable oils

Abstract

Trans esterification of three vegetable oils, sunflower oil, linseed oil and mixed oils as; sunflowersoyabean and olein were carried out using methanol, and potasium hydroxide as catalyst. The methyl esters of the corresponding oils were separated from the crude glycerol and characterized by physical-chemical methods to evaluate their thermal properties. This methods are determination of densities, cloud points, pour points, flash points, kinematic viscosities, hydrogen/carbon ratios, sulfur contents, ash contents and triglycerides. The physico-chemical characteristic of biodiesel treated with ozone showed improvement of pour point and flash point indicating higher degree of safety for fuel. Methyl esters mixed with their corresponding ozonated oil were subjected to comparison and evaluation for their thermal properties by the thermo gravimetric analysis differential thermal analysis from which the calculated heat of enthalpy and comparison with the heat of conventional diesel. The results showed that the oxygen content of biodiesel samples treated with ozone increased weight % and resulted in more extensive chemical reaction, promoted combustion characteristics and less carbon residue was produced. Gas chromatography appeared more suitable to address the problem of determining/verifying biodiesel methyl ester and showed that methyl ester content was impurity free. Ultra violet-detection was used for rapid quantization of triglycerols. From the analyses performed biodiesel treated with ozone modified the thermal and oxidative stability shown by the high combustion efficiency indicated by the high heat of enthalpy and reducing the emission of particulate matter.

Assessment of heavy metal pollution in the urban stream sediments and its tributaries

“…Sometimes they are co-adsorbed with other elements as oxides, hydroxides of Fe, Mn, or may occur in particulate form (Awofolu et al, 2005;Mwiganga and Kansiime, 2005). Heavy metals may enter into aquatic ecosystems from anthropogenic sources, such as industrial wastewater discharges, sewage wastewater, fossil fuel combustion and atmospheric deposition (Linnik and Zubenko, 2000;Campbell, 2001;Lwanga et al, 2003;El Diwani and El Rafie, 2008;Idrees, 2009). Trace elemental concentrations in stream sediment compartments can be used to reveal the history and intensity of local and regional pollution (Nyangababo et al, 2005a).…”

Correlation between the chemical structure of biodiesel and its physical properties

“…Bondioli et al (2002) reported that polymers formed during storage of biodiesel in controlled conditions are soluble in oxidized biodiesel, due to its high polarity, and become insoluble only when oxidized biodiesel is mixed with diesel fuel. The physico-chemical characteristics of biobiesel treated with ozonated oil indicated the improvement of the thermal and oxidative stability (El Diwani and El Rafie, 2008).…”

Degradation of common pharmaceuticals and personal care products in mixed solutions by advanced oxidation techniques

“…2) that ozone dissolution also might be enhanced in presence of UV irradiation. The process of ozone adsorption onto TiO 2 surface and its subsequent decomposition leading to x OH formation is significantly enhanced in UV-assisted TiO 2 -catalyzed ozonation (O 3 /UV/TiO 2 ) (Beltran et al, 2005;El-Diwani and El-Rafie, 2008;Gharbani et al, 2008). Thus, the very small ozone concentrations with O 3 /TiO 2 may be attributed to its adsorption onto TiO 2 surface, while both adsorption onto TiO 2 surface and enhanced decomposition in presence of UV might have resulted to further smaller ozone concentrations with O 3 /UV/TiO 2 .…”