Sharif Digital Repository

In this project, theoretical and experimental study of methane adsorption on Multiwall Carbon Nano-Tubes (MWCNT) has been performed. This study has been conducted in the way to achieve a suitable method for methane storage and transportation. To carry out the experiments, the volumetric method was used up to 500 psia at various temperatures of 298.15 K, 303.15 K, 308.15 K. The effect of moisture was also studied at 298.15 K. Also, various adsorption isotherms were used to model the experimental data collected in this work. The results showed that the amount of methane adsorbed on the MWCNT can decrease with increasing the moisture and temperature of the adsorption cell. In order to... 

Phenolic compounds are important environmental pollutants that the removal and separation of them from the water and industrial wastewater especially in the oil industry is essential before entering the environment. In the present study, the removal efficiency of the adsorbent silica aerogel 4-Chlorophenol and 4-Bromophenol as phenolic compounds from aqueous solution was surveyed. In this research, the effects of various factors such as contact time, pH, and initial concentration of the pollutant and the adsorbent on the adsorption were studied. It was observed that there is a large amount of adsorption in acidic pH and this amount increases by incrementing the concentration of the... 

This project surveys bioregeneration of granular activated carbons contaminated with phenolic compounds. To carry out this survey, the procedure of phenol absorption on the surface of activated carbon was studied and their adsorption isotherms were calculated. In the first step, newly activated carbon was contaminated with phenol solution and optimum amount of carbon in phenol elimination was 0.5g. Then, the effect of time contact on phenol elimination was studied and eventually 1 hour of time contact was determined as the equilibrium time of phenol adsorption. In the second step, kinetics of adsorption of phenol and different stages of adsorption were studied. The results of this study... 

Xylene isomers have similar boiling points and, therefore, their separation by conventional distillation is not practical. The industrial separation of these isomers is generally performed by adsorption or crystallization processes, which are very energy consuming. In this work, the various methods of the separation of these isomers have been reviewed and the equilibrium adsorption of these components in liquid phase using two commercial types of zeolite including Z-700 and Na-BETA as adsorbent at 15, 25, and 35 oC and an initial concentration range of up to 50 wt% as well as in single and binary solutions was investigated. It was found that Z-700 adsorbent has no selectivity for the binary... 

Heavy metals, present in many industrial wastewaters, are considered as major pollutants of environment. Various methods to removal heavy metals effectively from effluents have been used in industry, yet more efficient and economical methods are required. Magnetic iron nanoparticles are known for their superior adsorption, ion exchange and electro-static forces characteristics.The aim of this study was to evaluate the efficiency of magnetic nanoparticles for removal of hexavalent chromium (VI) and Divalent nickel from wastewater and the parameters that influence the removal.The magnetite nanoparticles were prepared by co-precipitation method where produced Fe3O4 nanoparticle’s average size... 

Chemical flooding such as surfactant flooding in oil reservoirs can change the wettability and interfacial tension between oil and water and so reduce the residual oil saturation in the reservoir. Some of these materials can be adsorbed a lot on the surface of carbonate rocks, so it is difficult to predict the oil recovery factor in such process. Therefore it is necessary to survey the adsorption amount of surfactants in chemical EOR injections.In this thesis, the adsorption of a nonionic surfactant on the surface of carbonate rock is experimented and the proper model is obtained. Then the surfactant is injected in a core saturated with oil to observe the efficiency of this surfactant in... 

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... 

Olefin/ paraffin separation is one of the most important processes in the petrochemical industries.In the last decades, adsorption and membrane processes are a new technology considered significantly for this purpose. In order to synthesizeof zeolite powder (pure silica zeolite STT and CHA), raw materials were made by two methods and their HNMR spectrum was recorded and thenzeolite powder was synthesized. X ray diffraction(XRD) and scanning electron microscopy (SEM) images were taken,showing the same results as the refference structure.To consider synthesized zeolite powdersand olefin/ paraffin interactions, surface adsorption ofthose gases was accomplished on two zeolite powders. After... 

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... 

Heavy metals such as lead, chromium, nickel are considered as environmental pollutants. These substances are highly toxic and dangerous to humans and other organisms at low concentrations and many problems are caused by them. Chromium belongs to the group of heavy and toxic metals. Form 6-valent chromium for humans is considered a definite carcinogen and also creates other problems. One common method of chromium removal is chemical precipitation which caused a large volume of waste. Other methods such as ion exchange, solvent extraction, reverse osmosis and biological methods are used to remove chromium. Adsorption is another effective method with very few disadvantages compared to other... 

Porous polymeric particles have the extensive application in various sciences and various methods have been introduced for production of these particles. Depending on method of production, porous polymeric beads can be produced in diverse shapes, pore size, pores interconectivity, surface morphology and chemical properties. In common methods for production of porous polymeric particles, tuning the size and porosity is difficult or even impossible. Porous polymeric beads with the vast surface area and good functionality have been applied for adsorption of various materials. The purpose of this study is therefore to investigate a new procedure for the production of porous polymeric... 

Today, with expanding industries, wastewater treatment of them is a global problem. Heavy metal is one of the most common and most dangerous contaminants in waste water that over time, with the strict standards of output, find more effective ways of eliminating them has always been a challenge. New methods, especially in the field of adsorption have achieved promising results in many cases.
Polymers composites are one of the adsorbent for the removal of these contaminants have been considered. In this project Aniline and composites to remove arsenic and chromium were studied. In polymers synthesis factors like type of additives and oxidizing materials strongly effected on morphology of... 

The aim of this work was to investigate the performance of different kinds of Linde type A zeolite (LTA) for the dehydration of Tetrahydrofuran (THF)-water solution. Batch experiments were carried out to evaluate the effect of various operating parameters such as contact time, initial concentration, mixing temperature (10, 15,and 25 C), amount of adsorbent, and zeolite type(3A, 4A, and 5A zeolites). In theoretical studies, we took the advantage of several types of equilibrium model isotherms such as Langmuir, Freundlich, Dubin-Kaganer-Radushkevich (DKR) to describe the experimental adsorption data. Besides, three adsorption kinetic models including pseudo-first-order, pseudo-second-order,... 

In this thesis, the copper oxide - zinc oxide nanocomposite was synthesized and functionalized using 3-aminopropyltrimethoxysilane. The functionalized nanocomposite was characterized using X-ray Diffraction spectroscopy (XRD), Fourier Transform Infrared (FT-IR), X-ray Fluorescence Spectroscopy (XRF), Scanning Electron Microscopy (SEM) and Brunauer–Emmett–Teller (BET). Dye removal from synthetic wastewater was done in a batch system using functionalized copper oxide - zinc oxide nanocomposite as adsorbent. Direct red 23, direct red 80 and direct red 81 were used for preparation of synthetic wastewaters. The effects of operational parameters such as adsorbent dosage, initial dye concentration,... 

In this study, In order to reduce volatile organic component (benzene, toluene, xylene and ethyl benzene) some appropriate nanostructures were used. First the appropriate nano structures were identified, then modified and optimized and finally characterized by XRD, SEM, ASAP. Appropriate nano adsorbent such as nano active carbon, single wall and multi wall nano carbon tubs , nano fiber carbon, graphene oxide, aluminum oxide particles, nano-zinc oxide , titanium oxide particles, 13x zeolite and extruded nano carbon tubes, were prepared and optimized, than evaluated from perspective of the crystal structure, surface area and porosity. nano active carbon, single wall and multi wall nano carbon... 

In this project, polymer nanocomposites containing graphene oxide were prepared and used for adsorption of several cationic and anionic dyes. In most cases, these nanocomposites were prepared as three-dimentional polymer networks which contain graphene oxide. Nanocomposites with direct grafting of polymer chains onto the surface of graphene oxide were also prepared. Graphene oxide is an oxidized carbonaceous material with unique properties. This material has high surface area, good mechanical strength and various functional groups. Polymeric compounds with different functional groups, structures and properties can be prepared and used. By preparing composites of graphene oxide and polymers,... 

Generally, predicting the adsorption and Catalytic characteristics of the solids base on the primary principles is impossible; this is only possible for small molecules and single crystal surfaces. On the other hand, phenomenological approaches, which are based on experimental data, are efficient approaches in many cases. The best predictions and designs are done by those who have an extensive information “resources” about the “Reactive Substances- Catalytic-conditions” and are able to “analyze” the data based on the “chemical physical Models”. A Neural network is an extremely simplified model of the human brain that predicts a complex characteristic(s) from a series of primary... 

Because of the importance of purification units at the refineries, in this research the process of sulfur removing compounds from light naphtha product with 1 ppm concentration by adsorption method in a fixed bed tower was simulated by COMSOL Multiphysics software. In this work, simulation was done using two macro and micro perspectives. In the Macro-scale mass transfer takes place between the spherical particles of catalyst and in the micro-scale mass transfer takes place within the spherical particles and these two scales were coupled together by reaction rate variable. In Macro-scale one-dimensional and two-dimensional geometry were considered for model. Naturally, the result of the... 

Organic dye couldn’t be treated by conventional method (biological method) due to their durable structure. In recent years, graphene based adsorbent has become more popular; this is because of high specific surface area and presence of numerous functional group on its surface. Due to the widespread application of organic dye in different industry especially in textile industry, stability and toxicity nature of them, finding an appropriate and cost effective method in treatment of this pollutant is very important. In this study, preparing and characterization of 3-D gel magnetic graphene oxide/kappa carrageenan was conducted and its ability of dye adsorption was tested. For this purpose, at... 

In this research, a review on fluoride adsorption revealed that the modification of the adsorber surface with ions like Ca2+ results in great enhancement of the fluoride adsorption. It seems that the enhancement in fluoride adsorption by the modified adsorber, is mainly due to the selective chemical binding of the fluoride ion with the surface-bound ion (Ca2+), regardless of the base material itself. In order to confirm this hypothesis, two different adsorber materials namely, γ-alumina (a material, conventionally used for fluoride removal from water and wastewater) and Micro-silica (a mineral with small adsorption capacity for fluoride) were selected for further study. It was found that the...