Journal of Applied Chemical Research
Volume:7 Issue: 2, Spring 2013

The fuel resistance property plays an important role in asphalts, but available standards for determining this characteristic are presently lacking. In the present work, a number of polymer modified bitumen with styrene-butadiene-styrene (SBS) polymer (4, 5, 6% SBS) and SBS/ sulfur modified bitumen with various percentages of sulfur (1.65, 3, 3.5% based on polymer content) were prepared. Each sample was immersed in the fuel and after 24 hour its weight loss was measured to determine the effect of fuel on them. Results showed that, increase in SBS content caused improvement in physical and rheological properties of bitumen. After adding sulfur to SBS, conventional properties (softening point, penetration, ductility and temperature susceptibility) was improved. Rheological properties were determined by Dynamic Shear Rheometer (DSR). Increase in polymer content and sulfur level led to increase in complex shear modulus (G*) and improvement of the rutting factor. Results indicated that more physical bonds with increase in polymer content and more chemically bonding between polymer, sulfur and bitumen by increasing in sulfur content led to more fuel resistance characteristic.

Cloud point extraction (CPE) as a rapid, simple and efficient method coupled with high performance liquid chromatography (HPLC) was used for sample preparation and subsequent determination of carbazole, trinitrocarbazole (TrNC) and tetra nitro carbazole (TNC) in water samples. Some effective parameters on extraction, such as volume of Triton X-100, extraction time, extraction temperature, ionic strength and centrifuging time were studied and optimized. Under the optimum conditions, recoveries of analytes were in the range of 98.0–102.0 . The calibration curve was linear in the range of 0.08 to 15.0 μg mL−1 for TNC, 0.06 to 15.2 μg mL−1 for TrNC, and 0.08–21.0 μg mL−1 for carbazole. Limit of detection (LOD) and limit of quantification (LOQ) were in the range of 0.009 -0.01 and 0.06-0.08μg mL−1, respectively. The relative standard deviations (RSDs) were in the range of 4.0- 6.2 %. The obtained results show that CPE with a high performance liquid chromatography (HPLC) is a sensitive and simple method for the determination of carbazole, TrNC and TNC in water samples.

The research in new organic π-conjugated molecules with specific properties has become one of the most interesting topics in fields of materials chemistry. These materials are promising for optoelectronic device technology such as solar cells. On the other hand, the use of low band gap materials is a viable method for better harvesting of the solar spectrum and increasing its efficiency. The control of this parameter of these materials is research issue of ongoing interest. In this work, quantum chemical investigation has been performed to explore the optical and electronic properties of a series of different compounds based on thiophenephenylene. Different electron side groups were introduced to investigate their effects on the electronic structure. The theoretical knowledge of the HOMO and LUMO energy levels of the components is basic in studying organic solar cells so the HOMO, LUMO and Gap energy of the studied compounds have been calculated and reported. These properties suggest these materials as a good candidate for organic solar cells.

Titanium dioxide has been widely used for photo-catalytic and self-cleaning activities. In this study, TiO2/SiO2/Co nanocomposite was prepared by sol-gel method in the presence of Polyvinyl Pyrrolidone (PVP), and Hydroxyl Propyl Cellulose (HPC) as additives, and characterized by IR spectra, Scanning Electron Microscopy (SEM), Energy Dispersive Analytical X-Ray (EDAX), and X-Ray Diffraction (XRD) methods. The influence of metal doping and additives effect onto TiO2/SiO2 on the structure and photo-catalytic behavior was evaluated. Moreover, Photo-catalytic activity was investigated in different conditions. The results revealed that the photo-catalytic activity of TiO2/SiO2 doped with appropriate content of Cobalt in the presence of additives exceeded, and TiO2/SiO2/Co nanocomposite with HPC had the best photo-catalytic activity.

The structures and properties of [n]sila-acenes (n=2-4) were investigated by density functional theory method. The results of calculations were obtained at B3LYP/6-311G (d,p) level on model species. Energetic criteria suggest that 2-1b (n=2), 3-1b (n=3), and 4-1b (n 4) isomers enjoy stabilization. By frontier orbital analysis, these systems are among the most stable of the family. Also, calculations indicate the most stable isomers have the most first hyperpolarizability values. The aromaticity of all molecules has been studied by nucleusindependent chemical shift.

Maghemite and magnetite nanoparticles and nanorode are now losing interests in the field of nanobiotechnology and pharmaceutical for their applications. This paper reports on a hydrothermal process for the synthesis of Fe2O3 in the γ-phases nanorodes, when the hydrothermal temperature was 100 ̊C. The uniqueness of the method lies in the use of ferrous ammonium sulphate, hexamine was added as the stabilizer and hydrolyzing agents. The crystal structure, shape particle and magnetic properties of the samples were determined by X-ray diffraction (XRD) and Transmission electron microscopy (TEM) and magnetometer (AGFM), respectively. The particle size was 60nm and length in the range of 300nm. The magnetic behavior of the particles was like the typical behavior of superparamagnetic particles, so smaller particles can improve the magnetic properties and decreasing the coercivity.

A new selective reagent was used for simultaneous determination of mercury and palladium in real samples with their different kinetic spectrophotometric properties. The method is based on the difference in the rate of the oxidation reaction of the recently synthesized reagent, nitro benzoyl diphenylmethylen phosphorane (N-BDMP), with Hg2 and Pd2. The kinetic profiles were monitored and recorded at maximum wavelength of reagent, and the data obtained from the experiments were processed by a chemometric approach (principal component analysis-artificial neural network models (PCFFNNs)). Performances of the proposed method were tested with regard to relative standard error (RSE), using synthetic solutions. Under the working conditions, the proposed method was successfully applied to the simultaneous determination of Hg2 and Pd2 in water, waste water and urine samples. The results showed that mercury and palladium could be determined simultaneously in the range of 4.00×10-7 to 1.00×10-4 mol L-1(0.08 to 20.06 μg mL-1) and 1.00×10-6 to 1.00×10 4 mol L-1 (0.11 to 10.64μg mL-1), respectively. Investigation of the effect of other metals on the system shows that this reagent is very selective for these two analytes and other metal ions do not show any interference.

This study investigated the efficiency of electerocoagulation (EC) in removing color from synthetic and simulated textile wastewater. The study on decolorization of mixed dyes is a step toward an effective treatment of textile wastewater. Two representative reactive dye molecules were selected for the synthetic dye wastewater, a blue dye alone and mixed dye (black, blue, red, 1:1:1v/v). The EC technique showed satisfactory color (98 %) and chemical oxygen demand (85%) removal efficiency and reliable performance in treating both individual and mixed dye types. The removal efficiency and energy consumption data showed that, for a given pH and optimum current density:100A/m2, Fe or Al were used in treating the dyes with an initial concentration of 100-1200 mg/L, the energy cost in achieving above 98% color removal was on order of 0.73-1.27kWh/m3 wastewater in all systems, water recovery was 0.97. It was found that the operating parameters used for the synthetic dye wastewater were less effective for treatment of simulated textile wastewater.