Iranian Journal of Chemical Engineering (IJChE)

Abstract Sorghum bicolor L., a plant of Gramineae family is a perenial grass which is grown in many parts of tropical and warm temperates of the world. Sorghum seeds are rich in carbohydrates and can be used as fermentation medium providing it is produced through proper extraction and sacharification processes. In this study, the fermentation capacity of an aqueous or ethanolic extract from sorghum seed was investigated in Lab-scale bioreactors by using three selected Lactobacillus species including L. delbrueckii, L. acidophilus and a new isolated strain identified as a Lactobacillus sp.
Among the selected bacterial species, Lactobacillus delbrueckii was found to have unique characteristics as it could tolerate different physico-chemical conditions. Compared to other species, L. delbrueckii could remain metabolically active in high concentration of NaCl and lactic acid, which is particular to the fermentation of sorghum seed extract neutrilized by NaOH. L.delbrueckii could also tolerate high temperature and, additionally, was able to produce more lactic acid in high concentration of carbohydrate during fermentation process (Yield 85-90%). In conclusion, the results of this study demonstrated that hydrolysed sorghum seed extract has enough nutrients to support the efficient growth of lactic acid bacteria and production of lactic acid under favorable conditions (37°C, 100 g/L initial carbohydrate concentration).

Abstract Contrary to sandstone reservoirs, carbonate reservoirs have an oil-wetting nature. Water flooding of these fractured reservoirs with low permeability matrix blocks is not recommended unless a wettability alteration process is possible. Imbibition is an oil recovery mechanism for these types of reservoirs, if the rock matrix is water wet and there is enough water in fractures in contact with the matrix. Heavy matrix oil, high interfacial tension (IFT), oil-wet matrix sample, and limited contact area of matrix with water in fractures, requires additional effort to enhance the oil recovery by capillary imbibition. Surfactants can be injected into naturally fractured reservoirs to improve the capillary imbibition recovery performance. A well-known surfactant is Hexadecyl Trimethyl Ammonium Bromide (C 16TAB), which is an appropriate type of surfactant for these kinds of reservoirs. However, due to its high cost, it is rarely used in the real case
studies. In the present paper a simple and inexpensive method has been proposed for synthesizing this surfactant. Surfactant at different concentrations have been dissolved in high salinity brine, and the interfacial tension (IFT) between the aqueous solution and the oil has been measured by pendent drop method. In addition, the contact angle between the oil and the aqueous solution is measured by sessile drop method, and during the experiment, photos were taken every two seconds in order to analyse the IFT and the contact angle obtained. It has been found that reduction of IFT continues up to critical micelle concentration of the surfactant. Furthermore, a correlation has been obtained to predict the IFT between the oil and the high salinity aqueous solution containing different surfactant concentrations. Finally, the best surfactant concentration is obtained for reservoir case studies.

Abstract Biodegradation of a mixture of benzene, toluene, ethyl benzene, and o-xylene (BTEX) was studied in a two-bed biofilter. The packing material was a mixture of sugarcane bagasse and granulated activated carbon. Aspergillus Brasiliensis and Aspergillus Niger fungi were inoculated in the biofilter, separately. The effects of BTEX concentration, Empty Bed Residence Time (EBRT) and temperature on the biofilter efficiency have been studied. The results indicate that in the biofilter with Aspergillus Brasiliensis fungus, the removal efficiency approaches to 100% for the inlet load of 71.5 g.m -3 h -1 and EBRT of 2.7 min while total removal efficiency in the biofilter with Aspergillus Niger fungus is obtained for the inlet load of 140.3 g.m-3 h -1 and EBRT of 1.3 min. The maximum elimination capacity for this biofilter at inlet load of 223.08 g.m-3 h -1 and EBRT of 0.9 min is 188.95 g.m^-3 h ^-1 .

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Abstract Zinc oxide nano wire have been produced by simple thermal way heating Zn powder on alumina substrate at different temperatures from 600 °C to 1000 °C in furnace for a time period of 30 minutes under oxygen gas environment. The prepared samples were characterized by different characterizing techniques, scanning electron microscopy (SEM), X- ray Diffraction (XRD ), energy dispersive X-ray spectroscopy (EDS ), UV-Visible spectroscopy.In all photographs it is clearly seen that the growth of nano wires is initiated at outer surface of the ZnO porous grains. The growth is clearly started at the edge of the surface.The XRD characterization confirms the wurtzite hexagonal structure of synthesized zinc oxide.
The band gap of synthesized semiconductor Zinc Oxide is increased rather than the bulk Zinc Oxide.