An-Najah Staff

Thermogravimetry analyses have been employed to study the catalytic effect of different metal oxide nanoparticles on the thermo-oxidative decomposition of asphaltenes at isothermal conditions. Three metal oxide nanoparticles were considered in this study, namely: NiO, Co3O4 and Fe3O4. Results showed that the presence of nanoparticles decreased the activation energy of asphaltenes oxidation and enhanced the reaction rate. It appears that the thermo-oxidative reaction is metal oxide specific. The obtained kinetic data showed that NiO has the highest reaction rate followed by Co3O4 and then Fe3O4, which suggests a change in the reaction mechanism. Isothermal conversion for thermal oxidation of asphaltenes at 360 °C without nanoparticles and at 300 °C in the presence of nanoparticles. View high quality image (142K) ⺠Metal oxide nanoparticles enhanced the reaction rate of asphaltene thermo-oxidation. ⺠The thermo-oxidative reaction is metal oxide specific. ⺠NiO nanoparticles have the highest reaction rate. ⺠Differences in activation energy for different nanoparticles suggest different reaction mechanisms.

[NiCl₂(C₁₄H₁₂N₂)(H₂O)] complex has been synthesized from nickel chloride hexahydrate (NiCl₂·6H₂O) and 2,9-dimethyl-1,10-phenanthroline (dmphen) as N,N-bidentate ligand. The synthesized complex was characterized by elemental analysis, infrared (IR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy and differential thermal/thermogravimetric analysis (TG/DTA). The complex was further confirmed by single crystal X-ray diffraction (XRD) as triclinic with space group P-1. The desired complex, subjected to thermal decomposition at low temperature of 400 °C in an open atmosphere, revealed a novel and facile synthesis of pure NiO nanoparticles with uniform spherical particle; the structure of the NiO nanoparticles product was elucidated on the basis of Fourier transform infrared (FT-IR), UV-vis spectroscopy, TG/DTA, XRD, scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDXS) and transmission electron microscopy (TEM).

Kinetic studies for the non-isothermal decomposition of un-irradiated and γ-irradiated ruthenium(III) acetylacetonate in air were carried out. The results show that the decomposition proceeds in one major step in the temperature range of 150–250 °C with the formation of RuO2 as a final solid residue for un-irradiated Ru(acac)3. For γ -irradiated Ru(acac)3 with 102 KGy total γ-ray dose, the decomposition goes eventually to completion with almost 100% decomposition and proceeds in one major step, which contains four overlapping decomposition stages in the temperature range of 200–320 °C. The kinetics is shown to be non-isothermal, using both model-fitting and model-free approaches. Infrared (IR) spectroscopy and X-ray powder diffraction techniques were employed to follow the chemical composition of the solid residue obtained at different temperatures.

Kinetic studies for the non-isothermal decomposition of un-irradiated and γ-irradiated indium acetyl acetonate In(acac)3 with 102 kGy total γ-ray dose were carried out in static air. The results showed that the decomposition proceeds in one major step in the temperature range of 150-250 °C with the formation of In2O3 as solid residue. The non-isothermal data for un-irradiated and γ-irradiated In(acac)3 were analysed using linear Flynn-Wall-Ozawa (FWO) and nonlinear Vyazovkin (VYZ) iso-conversional methods. The results of application of these free models on the investigated data showed a systematic dependence of Ea on α indicating a simple decomposition process. No significant changes were observed in both decomposition behaviour and (Eα-α) dependency between unirradiated and γ-irradiated In(acac)3. Calcination of In(acac)3 at 400 °C for 5 hours led to the formation of In2O3 monodispersed nanoparticles. X-ray diffraction, FTIR and SEM techniques were employed for characterization of the synthesised nanoparticles. This is the first attempt to prepare In2O3 nanoparticles by solid state thermal decomposition of In(acac)3.

Kinetic studies for the non-isothermal decomposition of unirradiated and γ irradiated silver acetate with 103 kGy total γ-ray doses were carried out in air. The results showed that the decomposition proceeds in one major step in the temperature range of (180–270 °C) with the formation of Ag2O as solid residue. The non-isothermal data for un irradiated and γ-irradiated silver acetate were analyzed using Flynn-Wall-Ozawa (FWO) and nonlinear Vyazovkin (VYZ) iso-conversional methods. These free models on the investigated data showed a systematic dependence of Ea on a indicating a simple decomposition process. No significant changes in the thermal decomposition behavior of silver acetate were recorded as a result of γ-irradiation. Calcinations of γ-irradiated silver acetate (CH3COOAg) at 200 °C for 2 hours only led to the formation of pure Ag2O mono-dispersed nanoparticles. X-ray diffraction, FTIR and SEM techniques were employed for characterization of the synthesized nanoparticles.