Environmental Engineering,
A. Kazemi-Beydokhti; H. Hassanpour souderjani
Abstract
Due to the dangerous effects of sulfur in hydrocarbon compounds and its impact on environmental health, a new formulation based on surface-modified carbon nanotubes and a cobalt oxide has been prepared. Oxidative desulfurization is the main section of this process that is utilized to reduce this impurity. ...
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Due to the dangerous effects of sulfur in hydrocarbon compounds and its impact on environmental health, a new formulation based on surface-modified carbon nanotubes and a cobalt oxide has been prepared. Oxidative desulfurization is the main section of this process that is utilized to reduce this impurity. After decorating cobalt oxide on the surface of nanotubes, the TEM images and Thermogravimetric analysis were studied to evaluate the structure of this complex. The results show that the combination of metal oxide and functionalized nanoparticles presents better efficiency in sulfur removal. In addition, the reaction rate raised by increasing the number of functional groups on the surface of nanotubes. Then, the influence of temperature, reaction time and the concentration of the oxidizing agent in the sample was investigated. The results show that the higher temperature and higher number of oxidizing agents could provide better efficiency in the desulfurization process. Due to the presence of CNTs in the synthesized catalyst, it is possible that sulfur compounds adsorbed with CNT. By matching the data with the Pseudo first and second order adsorption kinetic, it was found that the adsorption is done as a Pseudo first order adsorption kinetic. Since the ODS process is performed by a chemical reaction, the reaction kinetics were adapted to the first order equation and calculate the activation energy required for the reaction. This result can be utilized for better desulfurization of hydrocarbon fuels for different applications.
Separation Technology,
P. Azadi; Sh. Hassanajili
Volume 14, Issue 3 , August 2017, , Pages 19-30
Abstract
In recent years, plasma treatments have given good results since they offer high technological efficiency with low waste generation. One of the most important characteristics of plasma methods is their action only on a thin surface layer, whereas the bulk of sample remains unchanged and the modified ...
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In recent years, plasma treatments have given good results since they offer high technological efficiency with low waste generation. One of the most important characteristics of plasma methods is their action only on a thin surface layer, whereas the bulk of sample remains unchanged and the modified material keeps its chemical and mechanical properties. In this research, polyurethane membrane surface was modified by low frequency plasma grafting with methacrylic acid and acrylamide monomers to alter solution-diffusion mechanism. We chose different parameters of plasma treatment and studied their effects toward maximum solubility, permeation and selectivity. The grafting on the surfaces was characterized by water contact angle measurement and atomic force microscopy. After confirming a successful grafting, we studied the effect of surface modification on permeation of CH4 and CO2. Significant increase in CO2 permeation and about 32 percent increase in CO2/CH4 selectivity was observed. Better results were obtained for low powers and acrylamide grafted surface.