Scientia Iranica
Volume:17 Issue: 2, 2010

Manganese oxide supported on alumina was prepared for methanation reaction by doping the manganese oxide based catalyst with noble metals, namely ruthenium, Ru and palladium, and Pd, via an impregnation method. The potential catalyst was calcined at 400C, 700C and 1000C for 5 hours separately. An in-house-built micro reactor with an FTIR detector and GC was used to study the percentage of CO2 conversion and also the percentage of CH4 formation. Ru/Mn (30:70)-Al2O3 calcined at 1000C was the potential catalyst, which gave 86.82% CO2 conversion and 61.94% CH4 yield at a reaction temperature of 200C. XRD analysis showed that the catalyst is of a crystalline phase, while FESEM illustrated the catalyst surface was covered with small and dispersed particles with an unde ned shape. EDX analysis revealed that there was 21.15% reduction of Ru in the spent catalyst compared to the fresh catalyst due to the migration of Ru particles into the porous support during the reaction. There was 5.39% reduction of surface area over the spent Ru/Mn (30:70)-Al2O3 catalyst, characterized by Nitrogen Adsorption analysis. FTIR analysis revealed that the catalyst surface is hydrated.

A photocatalyst semiconductor can be used to remove organic pollutants from wastewater in the presence of UV light. In this research, coupled ZnO/SnO2 semiconductors with 1:1 and 2:1 ratios were prepared using the co-precipitation method. The prepared coupled ZnO/SnO2 photocatalyst was tested towards the photodegradation of simulated N-Methyldiethanolamine (MDEA) under UV-irradiation ( = 365 nm, 100 V, 6 W). The ZnO/SnO2 was characterized using UV di used re ectance spectroscopy and X-ray di raction. The band gap energy for ZnO/SnO2 (ZS) catalyst calcined at 200C, 400C, 600C and 900C were 3.22, 3.13, 3.12 and 3.07 eV, respectively, while for Z2S were 3.71, 3.28, 3.16, and 3.14 eV, respectively. XRD results indicated that ZS and Z2S catalysts possessed mixed phases of ZnO, SnO2 and Zn2SnO4 at a calcinations temperature above 600C. The ZnO/SnO2 (2:1) catalyst, which was calcined at 600C for 9 hours, gave the optimum percentage photodegradation of MDEA with 39.18%. The percentage degradation of MDEA was measured using ion chromatography with retention time at the measured peak of 4-5 minutes. The optimum system was applied on the photodegradation of MDEA in petroleum wastewater. The percentage degradation of MDEA in petroleum wastewater was 23.38 %.

Some cis-dioxomolybdenum (VI) complexes with tridentate Schi base ligands derived from salicylaldehyde and aminophenols, aminoalcohol or o-aminobenzenethiol were examined as catalysts for epoxidation of di erent aliphatic and aromatic ole ns, with tert-butyl hydroperoxide as oxidant. All complexes exhibited high activity and selectivity for epoxidation of aliphatic substrates during a short time period (95% conversion of cyclooctene after 30 min). The epoxide yield increased with the nucleophilic character of ole n. The catalysts activation strongly depends on the reaction temperature and nature of the solvent. Epoxidation of ole ns by these catalysts is inhibited by ligands or coordinating solvents such as alcohols.

PbSe thin films have been deposited on microscope glass substrates by chemical bath deposition technique. The chemical bath consisted of lead nitrate, sodium selenate and triethanolamine solutions. The in uence of bath temperature on the properties of PbSe lms was investigated. The X-ray diffraction, atomic force microscope and UV/Vis Spectrophotometer were used to obtain the structural characterization, surface morphological and absorbance data, respectively. Based on the X-ray di raction results, the thin lms obtained were found to be polycrystalline in nature with cubic structure. The intensity of the (111) peak showed a signi cant increased as the bath temperature was increased from 40 to 80C. The lms deposited at 80C indicated that the crystallinity was improved and more PbSe peaks were observed. On the other hand, the grain size, lm thickness and surface roughness were increased while band gap energy decreased as could be observed in atomic force microscope and UV-Vis optical studies, respectively.

In this approach, electrodeposition was developed for separation of ultra traces of some heavy metals from the complex matrices prior to determination by ame atomic absorption spectroscopy. The electrodeposition is carried out at optimized parameters of pH and temperature of electrolyte, voltage and duration time of deposition. The calculated LOD for ED-FAAS for the interested elements was found as follows: 1.27 ng mL􀀀1 for Co, 0.14 g mL􀀀1 for Re, 1.56 ng mL􀀀1 for Ni, 1.84 ng mL􀀀1 for Au, 0.02 g mL􀀀1 for Pt and 6.67 ng mL􀀀1 for In. Characteristic concentration for Co, Re, Ni, Au, Pt and In in ED-FAAS technique are 1.72, 660, 2.67, 2.99, 30 and 9.60 ng mL􀀀1 with %RSD as 1.54, 2.69, 2.45, 2.77, 2.38 and 2.55, respectively. These elements were measured in some environmental samples. Concentration of Co and Ni in a mineral water are 12.46 and 21.43 ng mL􀀀1, respectively, concentration of Re in a molybdenum mineral concentrate is 4.65 g mL􀀀1, concentration of Au in a geological samples is 6.00 ng mL􀀀1. It was also found that the recovery test for spiked Pt and In to a waste water samples is promising using the proposed technique.

Production yield of solid-state (SSF) and submerged fermentation (SMF) on chitosan from Aspergillus niger was investigated. A. niger BBRC 20004 was grown on soybean residue and Sabouraud Dextrose Broth medium (2% glucose). Chitosan was extracted from the fungal mycelia using hot alkaline and acid treatment. Soybean residue at a moisture content of 37%, and 8.4  0.26% of nitrogen content produced the highest amount of chitosan, 17.053  0.95 g/kg dry substrate after 12 days. Also, chitosan was extracted from A. niger on Sabouraud Dextrose Broth medium in submerged fermentation (0.8455 g/l after 12 days of cultivation). The yield of chitosan isolated in SSF was about 15-20 times more than in SMF (Submerged Fermentation).

In this study, experimental data on the kinetics of methane and propane hydrate formation at constant volume were collected. The experiments were carried out in a batch reactor under different temperatures and pressures. The chemical anity was used for modeling of the hydrate formation rate in a constant volume process. In this method, the system was considered as a classical thermodynamic or macroscopic view. The results show that this method can predict constant volume experimental data well for both crystals I and II hydrate former.

The e ect of operation variables, such as the H2/CO molar feed ratio, gas hourly space velocity (GHSV), temperature, and pressure, on the catalytic performance of the Co/Mn/TiO2 catalyst prepared at the Research Institute of the Petroleum Industry (RIPI) was investigated, and optimum reactor conditions were obtained to produce the maximum amount of light ole ns. The catalyst was prepared by co-precipitation of Co and Mn phases in the presence of commercial TiO2 with maximum selectivity for ethylene and propylene production. It was found that the [H2]/[CO]=2/1, space velocity (GHSV) of 1800 h􀀀1, 280C temperature and 4 bar pressure were optimum operating conditions for the modi ed catalyst for the conversion of Synthesis Gas(SG) to light ole ns. The results were interpreted in terms of the structure of the catalyst. Characterizations of catalysts were carried out using XRD, SEM and BET speci c surface area.

A new three parameter Equation Of State (EOS) is developed based on well documented data, at three thermodynamic states of the critical point, the normal bubble point and standard condition. Besides these states, the EOS is designed to satisfy the condition of nearly zero Joule-Thomson (JT) coecients at the normal boiling point. Critical properties and densities at the normal boiling point and a standard condition of more than 100 pure uids were used. The new EOS is validated using experimental data and eight (8) of the popular EOSs, namely, SRK, PR, LLS, HK, MNM, SW, PT and ALS. The experimental data for pure uids include 331 data points of vapor pressure covering 12 uids and compressibility at the critical condition of 23 uids. For mixtures, the data includes 129 PVT data points of 12 reservoir uids [seven (7) of them are Sudanese crude oil considered for publication for the rst time and ve (5) from literature]. The new EOS is found to be superior to the existing EOSs in the prediction of PVT properties of mixtures with a grand average percent absolute deviation (AAPD) of 3.18%. It is also comparable to the existing EOSs in the prediction of vapor pressure despite the fact that existing EOSs are developed based on vapor pressure data the grand average AAPD is 2.0. In terms of compressibility at the critical point with the exception of LLS, the new EOS yields better results than all other EOSs considered in this work.

In order to investigate the feasibility and e ects of core permeability on capillary imbibition recoverable oil from carbonate cores, some laboratory tests were carried out at the EOR research laboratories of Sharif University, Iran. Outcrop rocks with di erent permeabilities were taken away from a recognized outcrop and used in these experiments. Special core analysis tests were run on two core samples to nd out relative permeability and end point saturations. Wellhead separator oil and gas samples were collected and recombined to a reservoir gas - oil ratio. A core ooding system with a capability of free and forced imbibition testing was designed and installed. A number of free and forced imbibition tests with di erent cores under reservoir conditions were conducted. The results of the tests revealed that capillary imbibition is an almost fast process at laboratory scale and the higher permeable cores will imbibe more easily. A good correlation could be obtained when the ratio of recovery factor to ultimate recovery factor versus a de nite function of time was plotted. From these experiments, it concluded that an up scaled relation can be perceived for very low permeable cores, the testing of which may take too long.

FeCrAl foils were coated with alumina. Washcoating solutions were prepared using di erent sol-gel methods. Method A uses an inorganic precursor of aluminum nitrate and a complexing agent of Acetylactone, method B is a hot hydrolysis of aluminum alkoxide, and method C is a modi cation of method B, by adding aluminum acetylacetonate. The last method, D, is a hydrolysis of aluminum alkoxide at room temperature. Washcoating solutions were deposited on FeCrAl foils through dip coating. Then, the coated foils were dried at 100C and calcined at 600C/3 for 2 hours. Ultrasound vibration tests showed a good adhesion of washcoat layers. Characteristics of the washcoat layers were determined by X-Ray Di raction (XRD), Scanning Electron Microscopy (SEM), Brunauer-Emmet-Telller (BET), and Thermal Gravimetric Analysis (TGA) tests. Results of BET tests show that surface areas in sol-gel methods are greater than those found in the suspension method, and the inorganic sol-gel method (method A) has a lower surface area than those found in organic sol-gel methods.