Papers by Keyword: Methanol

Abstract: Dimethyl ether (DME) is apromising alternative for substituting petroleum fuel including gasoline, liquified petroleum gas, and diesel. In this research, the utilization of red mud as catalyst was investigated to dehydrate methanol to Dimethyl Ether (DME). Red mud is a solid waste from the bauxite industry which lead to environmental issues if did not treat properly. The catalyst characteristics were determined in terms of porosity, crystallinity, elemental composition, and pores size distribution. The catalysts activity was evaluated in a fixed-bed reactor at temperature range 200-300 °C. The influence of different parameters, including temperature and type of catalyst were varied to obtain the optimum reaction condition. The results revealed that the highest methanol conversion was 68% at temperature of 300 °C when using calcined red mud catalyst.

Abstract: The structure of Candida rugosa lipase can be affected by solvents used in the enzymatic reactions. Using molecular dynamics simulation as a tool to study the Candida rugosa lipase structure, we studied the effect of various solvent systems, such as water, water-methanol, and water-methanol-ionic liquid. These solvent systems have been chosen because lipase is able to function in both aqueous and non-aqueous medium. In this study, pyridinium (Py)-based ionic liquids were selected as co-solvent. The MD simulation was run for 50 nanoseconds for each solvent system at 328 K. In the case of water-methanol-ionic liquids solvent systems, the total number of the ionic liquids added were varied: 222, 444, and 888 molecules. Water was used as the reference solvent system. The structure of Candida rugosa lipase in water-methanol system significantly changed from the initial structure as indicated by the RMSD value, which was about 6.4 Å after 50 ns simulation. This value was relatively higher compared to the other water-methanol solvent system containing ionic liquid as co-solvent, which were 2.43 Å for 4Py-Br, 2.1 Å for 8Py-Br, 3.37 Å for 4Py-BF₄ and 3.49 Å for 8Py-BF₄ respectively. Further analysis by calculating the root mean square fluctuation (RMSF) of each lipase residue found that the presence of ionic liquids could reduce changes in the enzyme structure. This happened because the anion component of the ionic liquid interacts relatively more strongly with residues on the surface of the protein as compared to methanol, thereby lowering the possibility of methanol to come into contact with the protein.

Abstract: Membrane Electrode Assembly (MEA) is the most important component in fuel cell devices. Electrodes composing MEA greatly determine the performance and durability of its application in passive Direct Methanol Fuel Cell (DMFC). Fabrication and characterization of electrodes with various loading Pt-Ru/C catalysts and their application to DMFC have been carried out. The XRD characterization results indicate the presence of C atoms which are indicated by the appearance of peaks at angles 2θ = 25°-30°. In areas, 44.4° and 45.1° indicate the presence of Ru even with low intensity and platinum in the area of 54.67°, 39.86°, 54.736°, 39.88°, and 68.3°. The highest ECSA value and electrical conductivity and low resistance showed the best catalytic activity possessed by electrodes with the loading of Pt-Ru/C catalyst 10 mg/cm². MEA with a catalyst loading of 8 mg/cm² is known to have a fairly large initial voltage before the load is given based on the results of Open Circuit Voltage (OCV) measurements. The MEA performance was observed based on I-V and I-P performance tests using the SMART2 WonAtech Fuel Cell Test Station on passive DMFC stacks with 3 M methanol as fuel. The best MEA shown in MEA with catalyst loading is 10 mg/cm² because it can maintain and achieve a voltage and power density that is quite higher than other MEAs in each load increase in the form of current density.

Abstract: TiO₂ modified Fe₃O₄ nanocomposite as photocatalyst in CO₂ indirect reduction was synthesized by an ultrasonic-assisted sol-gel method and its photocatalytic activity was studied as well. The modification of the TiO₂ composite was attempted to modify titanium dioxide to have better performance as a photocatalyst. Magnetite synthesis was carried out by the sono-coprecipitation method with the addition of the capping agent. The magnetite was coated with TiO₂ via the sol-gel method under ultrasonic irradiation. The products were characterized by X-ray diffraction (XRD), Fourier transforms infrared spectrophotometry (FT-IR), transmission electron microscopy (TEM), and turbidimetry. The final product was also analyzed by diffuse reflectance UV-Visible (DR-UV) and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX). The product of indirect reduction was analyzed by gas chromatography-mass spectrometry (GC-MS). Photocatalytic reaction with Fe₃O₄/TiO₂ nanocomposite produced a higher concentration of methanol than using TiO₂. Methanol concentration produced from the photocatalytic reaction using TiO₂ and Fe₃O₄/TiO₂ was 6.63% and 16.82%.

Abstract: Ti-6Al-4V titanium alloy is a high strength-to-mass ratio material common in a lot of engineering fields. Its surface oxide can guarantee the protection of the substrate from various corrosive media. Unluckily, this film can be scratched in presence of mechanical and chemical loads and for this reason the corrosion resistance can decrease. The Structural Mechanics Laboratory (SM-Lab) is carrying out a characterization of the alloy in different environments under quasi-static loading. In this paper, a summary of the outcomes of the investigation and the description of the fracture surface of a specimen with EDM notches quasi-statically tested in methanol is provided

Abstract: The present study describes the preparation of catalyst MoO₃ supported on smectite clay by the solution impregnation method and its evaluation as a heterogeneous catalyst in the production of biodiesel from soybean oil. The individual effects of catalyst (hard green clay and MoO₃/hard green clay) on kinematic viscosity of produced biodiesel and conversion were investigated. The samples were characterized by X-ray diffraction, X-ray fluorescence spectroscopy and N₂ adsorption-desorption. Conditions of soybean oil transesterification were: 5% catalyst by weight, 1:12 oil to methanol molar ratio, at 200 oC for 60 minutes. Patterns of X-ray diffraction showed the characteristic peaks of the structure of smectite. The results of X-ray diffraction suggests that MoO₃ species exist as highly dispersed surface species. Molybdenum metal identified as effective catalysts for the transesterification reaction of soybean oil with methanol. A preliminary design assessment show that this catalysts (MoO₃/HGC) is sufficiently active achieving conversion in excess of 62,07% at temperature below 200 oC.

Abstract: This study aims to determine the para-phenylenediamine (PPD) in hair dyes by High-Performance Liquid Chromatography (HPLC). In the presented study, ten hair dye samples were collected from local markets in El-Bieda - Libya. A rapid, simple and reliable method is developed and validated for the determination of PPD in hair dyes samples using 50% methanol solution as solvent. The method was validated over a wide linear range of 5 – 25 µg/mL with correlation coefficients being consistently greater than 0.997. The LOD and LOQ were 1.21 µg/ ml and 3.67 µg/ ml, respectively. Relative standard deviation (% R.S.D.) ranged between 0.07 and 1.15 %. The minimum PPD level was observed in Beauty Touch (Blonde) sample (0.0855 % w/w), while Jourin sense Cosmetics (Black Blue) sample showed the highest PPD content (2.2526 % w/w). The HPLC measurments indicated that the results of PPD concentrations in Black colour samples were in the range of 0.3705 % - 2.2526 % w/w. Whereas its concentrations in anthor colour samples were in the range of 0.0855 % - 0.5936 % w/w. The level of PPD in Black colour samples were higher than other colour samples. The PPD content in all the samples analyzed in this study are well below the allowable limits set by the US Food and Drugs Administration.

Abstract: Co-promoted Cu/ZnO catalysts were studied for Fischer-Tropsch synthesis (FTS). All catalysts were prepared by the co-precipitation method, having the mass ratio of Co:Cu:Zn=0 (unpromoted), 0.05, 0.5:1:1, and characterized by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), including X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). From XRD and XAS, the results confirmed the phase transformation of CuO to Cu foil and Co₃O₄ to Co foil in Co-promoted catalysts after reduction. After FTS reaction testing, the Co-promoted catalysts showed the decrease in methanol selectivity of 15 and 1.6% for 0.05Co-Cu/ZnO and 0.5Co-Cu/ZnO, respectively, and the increase in C₅-C₁₅ selectivity during 30 h of reaction.

Abstract: Ti-6Al-4V alloy in solutionized and aged condition was subjected to axial fatigue testing in air and corrosive environments respectively. Severity of the methanol damage as evidenced through fractographic studies, corroborates loss in fatigue strength of samples tested in methanol environment in contrast to samples tested in air. Samples subjected to fatigue loading in NaCl environment revealed extensive secondary cracks along alpha grain boundaries.

Abstract: According to the characteristics of methanol leakage hazard, a new kind of foam decontamination agent was prepared and tested. Experiments were conducted in a laboratory-scale apparatus, where the effect of composition and amount on the decontamination performance of the foam was studied in detail. Results showed that the decontaminating efficiency of the foam was above 92% with the volume of foam agent sprayed 3 times of the methanol leaked. Moreover, the thick foam layer could stably cover the liquid methanol for a long time, efficiently inhibiting the volatilization of methanol vapor. Such performance of the foam agent was much superior to that of the commonly used water mist and activated carbon powder. The results are expected to provide useful experimental data and theoretical basis for the practical emergence disposal of methanol leakage.