Sharif Digital Repository

Presence of sulfur components in liquid fuels should be controlled due to environmental issues and process considerations. In order to decrease the level of sulfurous compounds in crude gas-oil with 5750 ppmw sulfur, electrochemical oxidative desulfurization has been investigated over electrodes of copper and stainless steel because of their easy operation and mild process conditions. In this research, the effects of stirring rate, temperature, applied potential, sodium hydroxide addition as electrolyte media and water volume have been examined on the sulfur removal efficiency. The results show that electrical conductivity of gas-oil sharply increases with addition of electrolyte up to 613... 

A nanowire arrays system consisting of an ordered configuration of Pt, Ni and Co was constructed in single-bath solution through pulse electrodeposition. This structure was evaluated as a potential amperometric non-enzymatic sensor to detect glucose in alkaline solution. We observed a strong and fast amperometric response at low applied potential of 0.4 V vs. SCE over linear ranges of 0-0.2 mM and 0.2-8 mM glucose with sensitivities of 1125 and 333 μA mM-1 cm-2, respectively. We also observed a low detection limit for glucose of 1 μM. Correlation of the electronic and geometric modifications with the electrochemical performance characteristics enhanced catalytic activity of the electrode by... 

The objective of this study was to construct a novel model to be applied in a general manner to simulate microbial electrochemical cells (MXCs); for both microbial fuel cell (MFC) and microbial electrolysis cell (MEC). The liquid bulk was modeled based on the organic matters degradation to acetate via the anaerobic digestion process. Biofilm simulation was established based upon one-dimensional distribution and the dynamical electron transfer was completed by means of the conduction-based mechanism. We, for the first time, introduced biofilm local potential modeling for MEC simulation with general and simplified linear boundary conditions. The MFC-related part of the model was evaluated... 

The present study deals with the feasibility of a microfluidic microbial electrolysis cell (MEC) as an efficient biohydrogen generator for medical usage for the first time. The evaluation of nickel in microfluidic MEC as an alternative for conventional electrodes indicates successful performance in the improvement of bioenergy production. The maximum biohydrogen production rate and produced power density of 2.2 μW cm−2 and 1.4 μl H2 μl substrate−1 day−1 were obtained, respectively. It is considered a promising technology for medical usage due to the following factors: significant biohydrogen generation, low consumption of expensive materials, simple construction, and utilization of human... 

Electrochemical exfoliation of graphite has recently attracted a big attention as a simple, fast and scalable method for the preparation of high quality graphene, but there are some drawbacks that hinder its application. Direct deposition is one of the most critical challenges that makes it difficult to deposit uniform, compact and large scale graphene thin films. This work develops a facile electrophoretic deposition route to fabricate exfoliated graphene (EG) film on Ag nanowires (NWs) networks with a controllable film thickness in nanometers scale. EG thin films are deposited with different applied potentials and times from an EG dispersion in N, N-dimethylformamide solvent. Since... 

In the present work, an amperometric inhibition biosensor for the determination of sulfide has been fabricated by immobilizing Coprinus cinereus peroxidase (CIP) on the surface of screen printed electrode (SPE). Chitosan/acrylamide was applied for immobilization of peroxidase on the working electrode. The amperometric measurement was performed at an applied potential of -150. mV versus Ag/AgCl with a scan rate of 100. mV in the presence of hydroquinone as electron mediator and 0.1. M phosphate buffer solution of pH 6.5. The variables influencing the performance of sensor including the amount of substrate, mediator concentration and electrolyte pH were optimized. The determination of sulfide... 

Ce-doped ZnO and pure ZnO nanocomposite thin films with different Ce/Zn ratios (0, 2, 5, 10, 15, 20, and 30 at.%) have been prepared by sol-gel method at optimum annealing temperature of 500 °C. The synthesized samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis spectrophotometry. According to our XPS data analysis, there are three major metal ions namely Ce3+, Ce4+ and Zn 2+ that coexist on the surface. The XRD measurements indicate that the ZnO thin films have a hexagonal wurtzite structure, and CeO2 crystallites formed in the Ce-doped ZnO nanocomposite thin films. Photoelectrochemical property of the samples was studied by three... 

TiO2 nanorods have been successfully grown into a track-etched polycarbonate (PC) membrane by a particulate sol-electrophoretic deposition from an aqueous medium. The prepared sols had a narrow particle size distribution around 17 nm and excellent stability against aging, with zeta potentials in the range of 47-50 mV at pH 2. It was found that TiO2 nanorods were grown from dilute aqueous sol with a low, 0.1-M concentration. Fourier transform infrared spectroscopy (FT-IR) analysis confirmed that a full conversion of titanium isopropoxide was obtained by hydrolysis, resulting in the formation of TiO2 particles. X-ray diffraction (XRD) results revealed that TiO2 nanorods dried at 100 °C were a...