Sharif Digital Repository

The major obstacle in using natural gas as a clean and abundant fuel in transportation industries is the low density of energy obtained from its combustion. Adsorbed Natural Gas (ANG) is a useful method to increase the energy density and store the natural gas. The lower cost and higher safety have made it different from the other storage technologies. In addition, ANG can be useful to solve the lack of gas in the peak of consumption. Among all adsorbents, Activated Carbon (AC) has shown the highest adsorption capacity of natural gas. In the present project, walnut shell has been used as the precursor in the chemical synthesise of AC. The main effective factors in chemical activation, such as... 

In the first part of this research, for the first time, we introduced a flexible high performance graphene-based supercapacitor using silver fiber fabric as the current collector. The silver fiber fabric offers remarkable advantages such as light weight, mechanical flexibility and ease of integration with electronic textiles, which well-suited for wearable energy storage devices. A new hybrid material of graphene-silver fiber fabric (rGO/SFF) was prepared through a facile electrophoretic deposition of graphene and being used as a binder-free flexible supercapacitor electrode. In order to obtain the optimum condition, the effect of deposition time was investigated and a duration time of 10... 

Natural gas (NG) has emerged as an alternative energy source in transportation sector as it provides clean combustion and hence lowers exhaust pollution. NG can be stored as an adsorbed phase in porous materials and is referred to ANG. The use of adsorbent materials for storing NG, at relatively low pressure (3.5–4 MPa), is a possibility for making ANG technology competitive with CNG. Among all adsorbents, carbon nanostructures with pore diameter (0.8-1.4 nm) has shown the highest adsorption capacity of natural gas. In the present study, cellulose has been used as the carbonaceous precursor and Activated Carbon (AC) has been prepared using hydrothermal carbonization of cellulose followed by... 

Biodegradation is an effective method for removal of hazardous organic compounds such as styrene and ethylbenzene from petrochemical wastewaters. Although using this method for wastewater treatment meets (satisfies) the industrial standards, still these methods have significant disadvantages. Active sludge systems can not be effective enough due to the volatility and recalcitrance of styrene and ethylbenzene and a significant amount of volatile organic compounds exists in the discharging air. In order to reduce or totally remove this amount of pollutants in the discharging air, Membrane Bioreactors are used. One of the main problems of these systems is membrane fouling. In this thesis the... 

Silicon carbide due to its noticeable mechanical and thermal properties, uses in various industries either main substrate or reinforcement. SiC has low specific surface area according to its resistivity against sintering. Recently, a lot of scientists have been worked on SiC in order to fabricating small ones ; subsequently, better sintering will be achieved. Chemical vapor deposition method (CVD) is a method to produce fine SiC with deposition of products by reacting of initial materials from gas environment. In this study normal CVD as proper method and hydrogen, silicon tetrachloride and activated carbon as initial materials are chosen. Using of iron and nickel catalysts in temperature... 

In this study, granular activated carbon has been modified by potassium nickel hexacyanoferrate ( KNCF), sodium dodecyl sulfate(SDS) and ammonium per sulfate(APS) as new adsorbents for cesium, cobalt and chromium(VI), respectively. The prepared adsorbents were characterized using powder X-ray diffraction(XRD), nitrogen adsorption-desorption isotherm data, infrared spectroscopy, scanning electron microscopy coupled with energy dispersive spectroscopy(SEM-EDS) and their adsorption performance were investigated. The effect of various parameters like the initial pH value of the solution, contact time, temperature, strength ionic of the solution, interference ions and the initial concentration of... 

In this project, the feasibility of hydrocarbon waste water treatment with low concentration by physical- chemical treatment methods will be discussed. The purpose of this thesis is to investigate the feasibility of reusing the water outlet of the oil and gas refineries, in the region of ASALUYEH where there is an urgent need for water. By using activated carbon and wooden absorbent (absorption method) efficiency of this method was determined. Both coagulation and flocculation methods were investigated. To design and optimize various operating conditions on the adsorption process the RSM method was used. Temperature, residence time, feed concentration, amount of adsorbent, and adsorbent ... 

Emission of aromatic and aliphatic compounds to atmosphere is a major environmental concern for many urban societies. Catalytic oxidation of volatile organic compounds (VOCs) is an efficient and low operating cost technology for reduction of air pollution.
First, dispersed copper oxide nano-catalysts supported on almond shell-based activated carbon were prepared for catalytic oxidation of toluene in air. The Response Surface Methodology (RSM) was used to express the catalyst removal efficiency in terms of catalyst metal loading and calcination temperature. Calcination temperature had a significant effect on the catalyst activity only at high metal loadings (upper 8% wt.). Two different... 

The amount of fresh water suitable for various uses is decreasing day by day. This may be due to evaporation or contamination of water or such. Heavy metal cations, dyes, oils and solvents are the most important substances that contaminate water. There are various ways to remove these contaminants, one of which is the absorption of these substances by suitable absorbents. Carbon compounds have attracted much attention among all the absorbents used so far. The aim of this study is to produce carbon aerogels from an economic and modify its structure and properties by adding graphene nanosheets. In this study, Novalak-graphene oxide (GO) gel was fabricated using solvent-saturated vapor... 

The search for sustainable and clean energy sources to replace fossil fuels has become one of the most important scientific and technological challenges today due to the threat of fossil fuel shortages and environmental pollution. Therefore, the need for clean energy production and storage resources, including supercapacitors, has increased day by day. Today, supercapacitors have been considered suitable for energy storage due to their high-power density, appropriate energy density, long cycle life, and high safety. The aim of the present study was to obtain activated carbon fabric as electrode material in electrochemical energy storage applications and specifically supercapacitors. The...