Showing papers by "Mohammad Pazouki published in 2011"

Biodiesel production from genetically engineered microalgae: Future of bioenergy in Iran

Abstract: Current biomass sources for energy production in Iran include sewerage as well as agricultural, animal, food industry and municipal solid wastes, and are anticipated to account for about 14% of national energy consumption in near future. However, due to the considerable progress made in genetic engineering of various plants in Iran during the last decade and the great potentials of microalgae for biofuel production, these photosynthetic organisms could be nominated as the future source of bioenergy in Iran. An overview of status of bioenergy in the world and Iran as well as the potential and utilization of biomass in Iran is presented. The possibilities of increasing biofuel production through microalgal genetic engineering and the progress made so far are discussed. Biodiesel in the Iran and its future prospective is also reviewed, emphasizing the promising role of microalgae.

Room temperature synthesis of nanocrystalline anatase sols and preparation of uniform nanostructured TiO 2 thin films: optical and structural properties

Abstract: Transparent TiO2 thin films were deposited on soda-lime glass substrates via the sol?gel method using a nanocrystalline TiO2 sol solution prepared at room temperature employing the dip-coating method. The effects of pH on crystallinity, particle size and stability of the synthesized TiO2 sols were investigated, systematically. TiO2 thin films were thickened by means of a sequential dip-coating process. The TiO2 films were transparent and exhibited proper adherence. The effects of thickness and annealing temperature on the structural and optical properties of the thin films were evaluated. The prepared powder was crystalline without any thermal treatment. The crystallite size of the particles (anatase) was in the range 4.2?12.1?nm depending on the initial pH value. Although only the anatase phase was observed at room temperature and 400??C, a further increase in annealing temperature up to 700??C resulted in the formation of the rutile phase. Even at high annealing temperatures, fairly smooth and homogeneous surfaces with no cracks and pores were observed. It was demonstrated that the films were transparent in the visible region with characteristic absorption in the UV region. Band gap of the as-deposited film was estimated to be 3.34?eV and was found to decrease with increasing annealing temperature.

Study on Reaction Conditions in Whole Cell Biocatalyst Methanolysis of Pretreated Used Cooking Oil

Abstract: Biodiesel fuel (fatty acid methyl esters; FAMEs) can be produced by methanolysis of waste edible oil with a whole cell biocatalyst which is an attractive alternative to fossil fuel because it is produced from renewable resources. Utilizing whole cell biocatalyst instead of free or immobilized enzyme is a potential approach to reduce the cost of catalyst in lipase-catalyzed biodiesel production. Rhizopus oryzae (R. oryzae) PTCC 5174 cells were cultured with polyurethane foam biomass support particles (BSPs) and the cells immobilized within BSPs were used for the methanolysis of pretreated used cooking oil (UCO) for biodiesel production in this research. UCO is the residue from the kitchen, restaurant and food industries which promotes environmental pollution and human health risks. The inhibitory effect of undissolved methanol on lipase activity was eliminated by stepwise addition of methanol to the reaction mixture. The optimum conditions for the reaction were as follows: 50 BSPs, molar ratio of methanol to UCO 3:1, 15.54% (wt) water (in the form of buffer phosphate with pH= 6.8) based on UCO weight and temperature 35°C in three-step addition of methanol. The maximum methyl ester yield of 98.4% was obtained after 72 h of reaction in a shaken Erlenmeyer at mentioned conditions.

Potential of nano crystalline hydroxyapatite for lead (II) removal from aqueous solutions: Thermodynamic and adsorption isotherm study

Abstract: The potential of the synthesized nano hydroxyapatite to remove Pb (II) from aqueous solutions was investigated in batch reactor under different experimental conditions. The study also investigates the effects of process parameters such as initial concentration of Pb (II) ion, temperature and adsorbent mass. Various thermodynamic parameters, such as G°, H° and S° have been calculated. The thermodynamics of Pb (II) ion onto nano HAp system indicates spontaneous and endothermic nature of the process. Lead uptake was quantitatively evaluated using the Langmuir, Freundlich and Dubinin–Kaganer–Radushkevich (DKR) model. The adsorption data follow the Langmuir model better than the Freundlich and DKR model and the adsorption equilibrium was described well by the Langmuir isotherm model with maximum adsorption capacity of 714.286 mg/g of Pb (II) ions on nano HAp. Key word: Adsorption, nano crystalline hydroxyapatite, Pb (II), thermodynamic parameters, adsorption isotherms.