Nashrieh Shimi va Mohandesi Shimi Iran
Year:2015 | Volume:33 | Issue:4|Papers Count:11

The present study was based on an economical, eco-friendly, and efficient method for the green synthesis of silver nanoparticles in plant extract. This synthesis shows attractive characteristics such as; the use of inexpensive and available plant extracts, non-toxicity, eco-friendly biological materials, and operational simplicity. The extracts incubated with AgNO3 solution showed gradual change in color of the extracts to yellowish brown, with intensity increasing during the period of incubation. Characterization of synthesized silver nanoparticles was made by UV-Visible absorption spectroscopy, Transmission Electron Microscope (TEM), and X-Ray Diffraction (XRD) spectroscopy. The silver nanoparticles synthesized were generally found to be spherical in shape with variable size ranging from 5 to 30 nm, as evident by Transmission Electron Microscopy (TEM). The biosynthesized silver nanoparticles (AgNPs) showed good antibacterial activity against clinical strains of two bacteria (E. coli, and S. aureus).

The genus Phlomis is comprised of about 100 species, 17 are described in flora of Iran, among which 10 are endemic. In this work, we report on the antimicrobial activity and composition of the essential oil of Phlomis aucheri Boiss (Herbarium No: 91021, TARI) growing wild in Iran. The chemical composition of the essential oil of P. aucheri, collected from Tehran, Province of Iran, were analysed by GC and GC/MS. Fourty-seven components were characterized from the essential oil of P. aucheri, representing 92.88% of the total components were identified. E-anethole 24.58% was found to be the major constituent in the oil of P. aucheri, followed by germacrene D (11.1%), bicyclogermacrene (6.3%), spathulenol (6.01%), b-caryophyllene (5.58%), neryl acetate (4.58%) and germacrene B (4.53%). As mentioned before, sesquiterpenes (51.82%) were the major compounds in the oil of P. aucheri followed by non terpenoid compounds (27.74%) and monoterpenes (13.32%). The antibacterial activity of the essential oil of P. aucheri was evaluated against three gram positive and three gram negative bacteria strains. The results of antibacterial activity showed that the oil of P. aucheri had antibacterial activity against Bacillus anthracis. Antioxidant activity of the essential oil of P. aucheri was determined by three methods: The Ferric-Reducing Antioxidant Power (FRAP), Radical-scavenging capacity of the oil or bleaching of 2, 20-diphenylpicrylhydrazyl (DPPH) and b-Carotene-linoleic acid assay. The results suggest application of P. aucheri oil as a natural antioxidant agent.

In situ epoxidation reaction of soybean oil from the raw materials of acetic acid and hydrogen peroxide was performed for the first time in the presence of a heterogeneous catalyst, namely silica sulfuric acid within the temperature of 30-75oC. By altering the molar ratios of soybean oil, acetic acid and hydrogen peroxide and also the reaction temperature and percent of catalyst, the optimum condition of the epoxidation reaction for obtaining the highest value of epoxy percent in epoxidized soybean oil was achieved. The maximum oxirane value obtained in he product was 6% which was achieved at the optimum condition of the reaction, involving the molar ratio of soybean oil, acetic acid and hydrogen peroxide of 1: 0.5: 1.1 respectively, at the temperature of 60oC and in the presence of 5% catalyst. Moreover, in comparison with the other acid liquid catalysts usually used for epoxidation reactions, silica sulfuric acid have several advantages including ease of usage, being inexpensive, having high chemical activity and safety and being environmentally friendly.

In order to find a suitable sensitivity sensor for Mustard molecule as blistering agent, we studied the adsorption behavior of MU molecule on the exterior surface of (4,0), (5,0) and (6,0) zigzag Aluminum-Nitride Nanotubes (AlNNTs) by used of Density Functional Theory (DFT) calculations. Geometry optimizations were carried out at B3LYP/6-311G** level of theory. The equilibrium distances, adsorption energy, Dipole moment and energies of the Highest-Occupied Molecular Orbital (HOMO) as well as the Lowest-Unoccupied Molecular Orbital (LUMO) were calculated for the adsorption process of MU molecule on the aluminum-nitride nanotubes. Results show that the adsorption energy and the electronic properties of the AlNNTs depend on the AlNNTs diameter and orientation of the MU molecule outside the tube. The adsorption energies and equilibrium distances show that the 40S configuration (Sulfur atom of MU molecule is situated above a aluminum atom of (4,0) AlNNT) is most favorable. The quite small values of electron transfer (DN) and the slight effect of MU molecule adsorption near the Fermi level in DOS of (4,0) AlNNT shows an inconsiderable amount of electron transfer between the MU molecule and AlNNTs in the adsorption process.

Industrial wastewater with heavy metal ions is an environmental concern. Ions of heavy metals from non-biodegradable nature, high toxicity, carcinogenic and cumulative effects, are highly regarded. In this research, hydrometallurgical methods such as solvent extraction method and ion exchange to remove potentially toxic metals Pb, Ni, Cd, Zn and Cu wastewater from the aqueous phase of the industrial area of the Kerman province, including polyethylene, tile, ferromolybdenum factories, coal washing plant and coal mine were examined. In the cationic ion-exchange resin Dowex50wx8 (H+) with 200-400 mesh sizes for extracting organic solvent from Di-(2-ethylhexyl) phosphoric acid (DEHPA or HDEHP) is an organophosphorus and thinners were used as Cruising. In order to find optimal conditions, the effect of various parameters such as pH, the amount of resin, contact time and aqueous phase pH and the concentration of organic solvent in the solvent extraction method was investigated. According to the results, the best pH range between 4 and 6 were obtained for both methods. The optimum concentration of organic solvent extraction is 20% by volume in cruising. Results suggest that the elimination of potentially toxic metals from industrial effluent aqueous phase ion-exchange method is higher than that of organic solvent extraction.

In this study alumina powder was synthesized by precipitation method. Boehmite gel was produced by hydrolysis of aluminium nitrate at pH rang of 8-9 and temperature of 90oC. The obtained gel was dried at 110oC and extruded subsequently. Extrudes were dried and calcined at 600oC. The final product has a surface area of> 200 m2/g and mean pore diameter of 6.6-11.63 nm. The g- alumina extrudates were then wet impregnated with molybdenium and cobalt salts, respectively. To produce g-alumina supported CoMo catalyst (CoMo/g-alumina). The amount of impregnated metal was measured by XRF technique. TPR analysis was performed to determine the reduction power.

In the present work, an efficient method using ionic liquid, 1-Butyl-3-methylimidazolium hexafluorophosphate [C4MIM] [PF6] as extracting solvent in direct single drop microextraction followed by ElectroThermal Atomic Absorption Spectrometry (ETAAS) has been developed for the determination of Lead in environmental and biological samples. 8- Hydroxyquinoline (8-HQ) was used as chelating agent. Experimental parameters related to the performance of IL-SDME, such as the pH, the concentration of the chelating agent, the volume of the extraction solvent, the extraction time, the stirring rate, the temperature effect and the salt effect have been investigated. Under the optimized conditions, the linear range, detection limit (S/N=3) and reproducibility (RSD, n=10) were 20-1000 ng/L, 0.64 ng/L and 3.8%, respectively. All microextraction experiments were carried out at room temperature, 25±1oC. The method was applied to the analysis of environmental water samples such as tap, well, river water and biological samples such as human hair and saliva samples. The recoveriesat 200 and 300 ng/L spiked level was in the range of 93.6-102.7%. The main advantages of the proposed method are simple, low cost, rapid, high recovery, high extraction efficiency, good repeatability and volatile organic solvent-free.

In this study, effect of ethanol and anionic, cationic and non-ionic surfactants on circulation velocity, mixing time and gas holdup in a three phase (water and alcohol-air-PVC particles) concentric draft tube airlift reactor have been investigated. In this experiments, Changing of gas velocity, liquid level and solid loading was investigated. Airlift reactor with height, internal tube diameter, outer tube diameter 173, 5 and 8 centimeters respectively, was made of glass. In gas-liquid-solid systems, with increasing gas velocity, gas holdup in riser and liquid velocity increases. The results show that gas holdup increases, surface tension and liquid circulation velocity decreases in the presence of alcohol, furthermore the results illustrate that non-ionic surfactant has greatest impact in proportion with cationic surfactant and ionic surfactant on gas holdup. In this study, the equation has been proposed for liquid velocity and gas holdup and mixing time.