mahboobeh mohammad

It is probable to take into account the presence of liquid hydrocarbon in case studies related to hydrate formation risk. Hydrate formation kinetic may be influenced by liquid hydrocarbon in result of mass and heat transfer resistance of phases. In this fundamental research, the effect of liquid hydrocarbon presence on nucleation and growth  steps of methane hydrate formation has been investigated. For this purpose, the experiments have been carried out considering two different cooling rates and volume ratios of liquid hrydrocarbon to water, and then parameters like induction time, induction temperature, percent conversion of water to hydrate and growth  time of hydrate completion have been measured and/or calculated. Regardless of different cooling rate, it is observed that the presence of liquid hydrocarbon has lowered induction time and induction temperature, that is moderating the nucleation step. Moreover, the presence of liquid hydrocarbon has shown a significant effect on the percent conversion of water to hydrate and the growth  time of hydrate completion. Generally, dispersion of water droplet through liquid hydrocarbon has increased water interface followed by a layered hydrate formation mechanism around the water droplets, this led to a decrease in percent conversion of water to hydrate and the growth  time of hydrate completion in comparison with blank experiments. Finally, hydrate formation kinetic and water to hydrate conversion have been more limited by increasing the volume ratios of liquid hydrocarbon to water.

Polyaniline and their nanocomposites were prepared by using chemical oxidative polymerization method in the presence of potassium iodate as oxidant. In this research, morphology and chemical structure of polyaniline/polystyrene and polyaniline/polyvinyl chloride was studied. Also, the capability of these nanocomposites to removal of zinc & lead cations from aqueous solution was studied. In order to adsorption of metal cations from aqueous solution, batch system was used & various experimental parameters such as ph, cationic pollutants dosage and contact time was evaluated. Results indicated that the highest adsorption rate for zinc and lead cations by polyaniline/ polyvinylchloride adsorbent was calculated 95.86 and 93.4, respectively. The optimum condition for lead cation adsorption were achieved using a polyaniline/polyvinyl chloride adsorbent at pH 7, a cation concentration of 100 mg/L and contact time of 20 minutes. Also, the study of adsorption isotherm equations has shown that the Freundlich equation is better compatibility with experimental data.