Sharif Digital Repository

The increasing utilization of silver nanoparticles (Ag-NPs) in industrial and consumer products has raised concern to wastewater treatment utilities, due to its antimicrobial activity. In this research, recovery of silver nanoparticles from wastewater via using activated carbon and convert it into usable nanoparticles is presented. real waste of silver nanoparticles have been used and activated carbon as adsorbent has a high absorption recovery for silver. Under the optimized experimental parameters e.g. pH, temperature, time of process, and amount of activated carbon, an absorption maximum was achieved and over than 99% of silver nanoparticles can be removed from wastewater. After the... 

Cane sugar impurities cause reduse production sugar in cane sugar industry.These impurities include polysaccharide for example starch, dextran and inorganic ash constituent such as potassium, sodium calcium magnesium and silica .The amount of impurities in the cane sugar depend on many factors including variety , grooving conditions and regional climate. Removal of impurities from cane sugar juice by clarification is an essential part of process of raw sugar manufacture. This process is based on the addition of lime, phosphates and polyelectrolyte. In this study effect of the amount of lime, phosphates and poly electrolyte on removal of various impurities has been investigated.In addition... 

Activated carbon, as an adsorbent with a high adsorption capacity and low cost, has many applications in liquid and gas adsorption processes. Among the adsorption of liquid phase, there are examples of drinking water purification, wastewater treatment, food industry, brewery, chemical separation (acids, amines, glycerin and glycols), enzymes ... and in adsorption from the gas phase there are examples of removing toxic compounds Containing sulfur and recycling sulfur, purifying biogas, use in gas masks, etc. Various materials can be used as raw material to make activated carbon. Materials such as walnut, almonds, coconut, pine, corn, etc. In this thesis, a feasibility study on the production... 

In this research performance of microbial fuel cells (MFCs) in continuous flow mode was studied. Different anodic chambers were tested and it was found that granular activated carbons (GACs) produced the highest power density (1228 mW/m3) in comparison with multiple anodes (731 mW/m3), single anode (294 mW/m3) and polymeric packings (40 mW/m3). It was also shown that in a plug-anodic chamber (PAC) the power output is reduced by reducing agitation of anodic volume. Adding more GACs to anodic chamber results in power increase, however by increasing occupied volume from 80% to 100% the power increase was negligible in result of cathodic reactions limitations. Feed flowrate was increased from... 

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... 

Nowadays, increased pollutants in the air threat the society health condition and Volatile Organic Compounds (VOCs) are the most hazardous ones among them. In the present study, catalytic oxidation as a prominent of the VOCs removal method from air, have attracted attentions due to high removal efficiency and suitable kinetic reaction. Because of its common industrial applications, toluene is intended to be eliminated through a low cost carbon supported catalyst which is synthesised in the laboratory. Construction method, carbonaceous support type, catalyst metal and its load, calcination temperature and time are among influencing design characteristics. A combination of Impregnation and... 

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... 

Pure NanoParticles of TiO2 and Nanocomposite catalysts of TiO2 , activated carbon (TiO2/AC) and multi-walled carbon nanotube (TiO2/MWCNT) were prepared by a sol –Gel method using TetraisoPropylorthotitanat (Tipt) as a precursor. The catalysts were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance uv-vis spectroscopy (DRS) and N2 adsorption – desorption measurements. The photoactivity of samples was evaluated by Acid Blue 92 (AB 92) degradation. The analysis results show that compared with pure Nanoparticles of TiO2, the spherical – shaped TiO2 particles are well – dispersed in TiO2/AC. In TiO2/MWCNT, the coating has special mechanism that... 

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 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... 

CO2 as a green house gas plays a significant role in the global warming and weather changes. Absorption by means of amine solutions is the main industrial technique for separating of CO2 from gas mixtures. Hazards associated with high temperature during solvent recovery, large size of equipment, corrosion, solvent degradation, and other reasons has made researchers to look for alternative processes such as adsorption. The aim of this study was to synthesis and modify the nano adsorbent for CO2 capture. To fulfill this purpose, various nano silica structures were synthesized and the amount of adsorption of each sample was determined. To investigate the performance capability nano_adsorbents,... 

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... 

During fuel combustion, aromatic sulfur compounds in energy fuels convert into sulfur oxides, which cause major environmental problems such as acidic rain, global warming, and air pollution. Absorption desulfurization is one of the promising and economical methods to remove these sulfur compounds from fuels. Metal-organic frameworks (MOFs) are a class of nanoporous materials that are of interest for use as adsorbents due to their high specific surface area, unique surface adsorption properties, high adsorption capacity, tunable porosity, flexible dynamic behavior, and diversity in functional and metal groups. In this research, we first synthesized five metal-organic frameworks, namely... 

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... 

One of the methods for adsorption of natural gas that has economical, operational and environmental preferences as an alternative energy source is storage as an adsorbed phase in porous material. ANG is superior to CNG and LNG technologies in terms of economy and safety. Carbonaceous nanostructures with pore diameter of 0.8-1.4 nm can be proper adsorbents for methane adsorption. In this work, cellulose and lignin which form lignocellulosic material’s structure, has been used as precursor for producing activated carbon. The activated carbon prepared has been used as adsorbent for adsorption of methane. The use of hydrothermal pretreatment followed by carbonization and chemical activation is... 

Natural gas contains small amount of benzene, toluene, ethyl benzene and meta-xylene (BTEX). These compounds are soluble in amine solutions and accumulate in aqueous amine solution during sour gas removal process. They produce problems such as foaming in amine adsorption columns. The aim of this work is to study BTEX removal from aqueous amine solution by means of activated carbon. Three different commercially available granular activated carbons were used in experiments. Experiments were divided in static and dynamic adsorption categories. In the static tests, equilibrium adsorption of all three activated carbons were performed and the most effective activated carbon sample determined by... 

Some of the thermal power plants use heavy fuel oil as an auxiliary fuel instead of the fuel gas, especially in the cold seasons. In these plants, in order to reduce fuel viscosity, heavy fuel oil is heated in several stages including fuel storage tank, connection lines and oil supply to burner by heat exchange with returned steam from the turbine, which can lead to fuel leakage into the condensates. This contamination is in addition to the contamination that has resulted from leaking seals on steam driven equipments, such as pumps and turbines. Reusing these contaminated condensates as boiler feed water can lead to coking of hydrocarbons and deposition of a hard scale on boiler tube walls.... 

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 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... 

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 ...