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Synthesis, Evaluation and Modification of Suitable Metal–Organic Frameworks (MOFS) for Desulfurization of Hydrocarbon Cuts
, M.Sc. Thesis Sharif University of Technology ; Khorashe, Farhad (Supervisor) ; Hajjar, Zeinab (Co-Supervisor) ; Soltanali, Saeed (Co-Supervisor)
Abstract
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...
Development of Biocompatible and Fluorescent Platforms Based on Carbon Dots and Deep Eutectic Solvents for Detection of Some Carcinogenic and Antidepressant Compounds
, Ph.D. Dissertation Sharif University of Technology ; Bagheri, Habib (Supervisor)
Abstract
The main focus of this thesis was on fluorescence sensors development based on carbon dots and deep eutectic solvents. Accordingly, an attempt was made to synthesize carbon dots and modified with deep eutectic solvents as biocompatible sensors. Eventually, development and application of these sensors in analytical systems ultimately led to satisfactory and comparable results with previous methods. In the first project, a rapid and miniaturized fluorescent probe based on the ultrasound‒assisted formation of carbon dots (CDs) in a metallic deep eutectic solvent (MDES) was developed and conveniently implemented to detect 4-MeI in commercial dark soft drinks. In-situ synthesis of CDs-chelated...
Dye Removal from Wastewater Using Functionalized Copper Oxide–zinc Oxide Nanocomposite as an Adsorbent
, M.Sc. Thesis Sharif University of Technology ; Kariminia, Hamid Reza (Supervisor) ; Mahmoudi, Niyaz Mohammad (Supervisor)
Abstract
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,...
Kinetics and Mechanism Study of Chemical Pollutant Adsorption Using Organic Ligands Modified Nano-adsorbents
, M.Sc. Thesis Sharif University of Technology ; Golami, Mohammad Reza (Supervisor)
Abstract
Among various methods for purifying water from dyes, adsorption takes advantage of simplicity, high efficiency, no secondary-pollution, and inexpensiveness. In this project Halloysite nanoparticles were applied to prepare a series of modified polyAcrylamide- quince seed gum hydrogels (QS/PAAm/Haln). The obtained hydrogels demonstrated improved efficiency as adsorbent in removing methylene blue (MB) from aqueous media. The structure of the prepared hydrogel nanocomposites were identified by X-ray diffraction, Brunauer-Emmett-Teller surface area analysis, Fourier-transform infrared spectroscopy, scanning electron microscope and energy-dispersive X-ray spectroscopy. Kinetics, thermodynamic,...
Adsorption Processes in Capacitive Deionization
, M.Sc. Thesis Sharif University of Technology ; Taghavinia, Nima (Supervisor)
Abstract
Today the water crisis affects billions around the world.According to existance of large amount of salty water on the earth, it seems one of the best soloution is desalination of salty water.There are methods for removing ions from water such as thermal methods, membrane methods , chemical methods and capacitive deionization.Capacitive deionization is based on the deviation of ions in the electric field.CDI system contains of two conductive porous electrodes that an elecric field is applied between them.While the brine pass through the space between the elecrodes the ions are absorbed by elecrodes. After a while the electrodes get saturated so a reverse potential is needed to regenerate the...
Design and Optimization of Nitrogen Purification Unit based on Adsorption
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Abbas (Supervisor) ; Fakhroleslam, Mohammad (Supervisor)
Abstract
In this project, in search of localization and synthesis of adsorbent for nitrogen purification in Pressure Swing Adsorption (PSA) units, studies have been carried out where after the finalized analysis around the choice of the adsorbent for synthesis and unit design, CMS has been choosen. Despite the lower selectivity compared to zeolite adsorbents in absorbing and separating oxygen from nitrogen, this adsorbent has been used as the first adsorbent in the industrial gas production industry due to higher nitrogen recovery and lower nitrogen absorption after economic studies in this field. In these days you can find few companies that use zeolite adsorbents to make nitrogen generators....
Bubble in flow field: A new experimental protocol for investigating dynamic adsorption layers by using capillary pressure tensiometry
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Vol. 460, issue , 2014 , p. 369-376 ; Bastani, D ; Ulaganathan, V ; Miller, R ; Javadi, A ; Sharif University of Technology
Abstract
For many years the model of a dynamic adsorption layer (DAL) is well established as explanation for the behavior of rising bubbles in surfactant solutions. This model explains the velocity profile and the evolution of the shape of a rising bubble based on the hypothesis of the balance between the drag force and the structure of the adsorbed layer governed by Marangoni convection. However, direct measurements of interfacial properties of the bubble during rising are a real challenge. Here we present a new experimental protocol called "bubble in flow field" suitable for direct measurements of dynamic interfacial properties of a bubble surface using the capillary pressure tensiometry under...
Simultaneous separation of H2S and CO2 from CH4 by a high silica CHA-type zeolite membrane
, Article Journal of Membrane Science ; Vol. 470, issue , 2014 , pp. 159-165 ; ISSN: 03767388 ; Soltanieh, M ; Sharif University of Technology
Abstract
A high silica CHA-type membrane was synthesized by the in-situ crystallization method on a disk like α-alumina porous support to separate both acid (H2S, CO2) gases from methane. The membrane showed a permeance of 3.39×10-8mol/m2sPa for pure CO2with CO2/CH4 ideal selectivity of 21.6 at 303K and 100kPa pressure difference across the membrane. The membrane was also tested with N2 and O2 pure gases indicating a small O2/N2 selectivity of 1.2-1.4, which shows that this type of membrane is not suitable for O2/N2 separation. The membrane performance was also analyzed by binary (CO2-CH4) and ternary (H2S-CO2-CH4) gas mixtures, with compositions near the real sour natural gas (CO2: 2.13mol%, H2S:...
Electromechanical resonators based on electrospun ZnO nanofibers
, Article Journal of Micro/ Nanolithography, MEMS, and MOEMS ; Vol. 13,Issue. 4 , 2014 ; ISSN: 19325150 ; Mohammadi, S ; Zad, A. I ; Sarvari, R ; Shariatpanahi, S. P ; Sharif University of Technology
Abstract
We present fabrication, characterization, and experimental results describing electrical actuation and readout of the mechanical vibratory response of electrospun ZnO nanofibers. For a fiber with an approximate radius of 200 nm and a length of 70 ìm, a resonance frequency around 3.62 MHz with a quality factor (Q) of about 235 in air at ambient conditions is observed. It is shown that the measured frequency of the resonance is consistent with results from finite element simulations. Also, the measurements were performed in an enclosed chamber with controlled levels of ethanol vapor. The adsorption of ethanol causes a shift in the resonance frequency of the fibers, which can be related to the...
Investigation of asphaltene adsorption in sandstone core sample during CO2 injection: Experimental and modified modeling
, Article Fuel ; Vol. 133 , 2014 , Pages 63-72 ; ISSN: 00162361 ; Ghotbi, C ; Taghikhani, V ; Shahrabadi, A ; Sharif University of Technology
Abstract
In this work, asphaltene adsorption in a sandstone core sample under dynamic conditions and during miscible CO2 injection was studied using live oil sample which is close to real conditions in petroleum reservoirs. In order to investigate of damage in sandstone core sample by the deposited material such as asphaltene, the morphology analysis of sandstone core sample using scanning electron microscopic method was studied. Also analyses of the adsorbed material in sandstone core sample by Soxhlet extraction using an azeotrope mixture and with SARA method were performed. The experimental results show that by increasing the flow rate of injected CO2, the amount of asphaltene in retained material...
Effect of metal doping, boron substitution and functional groups on hydrogen adsorption of MOF-5: A DFT-D study
, Article Computational and Theoretical Chemistry ; Vol. 1044, issue , 2014 , Pages 36-43 ; ISSN: 2210271X ; Saboohi, Y ; Sharif University of Technology
Abstract
In the present work, adsorption of hydrogen molecules over a metal organic framework (MOF-5) has been investigated by using first principles density functional theory (DFT). Different strategies have been applied for improving hydrogen storage, i.e. metal doping, boron substitution and functionalization. The metal atoms used for enhancing hydrogen adsorption include Li, Ca and Sc. It is found that the binding energy between these metal atoms and MOF is not enough to prevent clustering. Therefore a number of carbon atoms are substituted by boron atoms and it is indicated that boron substitution enhances the binding energies, significantly. Also the results reveal that boron substituted MOF...
A new model based on multilayer kinetic adsorption mechanism for asphaltenes adsorption in porous media during dynamic condition
, Article Fluid Phase Equilibria ; Vol. 375, issue , 2014 , Pages 236-245 ; ISSN: 03783812 ; Ghotbi, C ; Taghikhani, V ; Shahrabadi, A ; Sharif University of Technology
Abstract
In this work, a new model based on multilayer kinetic adsorption mechanism has been proposed to account asphaltene adsorption in porous media under dynamic condition and the model was verified using experimental data obtained in this work and also with those reported in the literature. In the proposed model two steps are considered for asphaltene adsorption. The first step is taken as adsorption of asphaltenes on the surface of the porous media and the second step is taken as adsorption of asphaltenes on the asphaltenes already adsorbed on the porous media. The Crank-Nicholson method, central difference in space and trapezoidal rule in time, giving second order convergence in time was...
Numerical modeling of surface reaction kinetics in electrokinetically actuated microfluidic devices
, Article Analytica Chimica Acta ; Vol. 838, issue , August , 2014 , pp. 64-75 ; ISSN: 00032670 ; Amini, Y ; Saidi, M. H ; Chakraborty, S ; Sharif University of Technology
Abstract
We outline a comprehensive numerical procedure for modeling of species transport and surface reaction kinetics in electrokinetically actuated microfluidic devices of rectangular cross section. Our results confirm the findings of previous simplified approaches that a concentration wave is created for sufficiently long microreactors. An analytical solution, developed for the wave propagation speed, shows that, when normalizing with the fluid mean velocity, it becomes a function of three parameters comprising the channel aspect ratio, the relative adsorption capacity, and the kinetic equilibrium constant. Our studies also reveal that the reactor geometry idealized as a slit, instead of a...
Spotlight on kinetic and equilibrium adsorption of a new surfactant onto sandstone minerals: A comparative study
, Article Journal of the Taiwan Institute of Chemical Engineers ; Volume 50 , May , 2015 , Pages 12-23 ; ISSN: 18761070 ; Ghazanfari, M. H ; Rashtchian, D ; Sharif University of Technology
Abstract
This paper presents a state of the art review of adsorption models for a new plant-based surfactant adsorption onto sandstone minerals. The adsorption data at both kinetic and equilibrium modes were obtained from batch experiments. Four adsorption kinetic models, five two-parameter, and six three-parameter equilibrium models were used for interpretation of the obtained data. Among the two and three-parameter isotherm models applied, the Jovanovic and the Khan isotherms showed the best fit, respectively. And the pseudo-second order model presented a better fit than other kinetic models. Finally, a computer-based modeling approach was developed and used for predicting the kinetics of...
Synthesis, characterization, and cesium sorption performance of potassium nickel hexacyanoferrate-loaded granular activated carbon
, Article Particulate Science and Technology ; Vol. 32, issue. 4 , 2014 , pp. 348-354 ; ISSN: 02726351 ; Samadfam, M ; Fasihi, J ; Grayeli Fumeshkenar, F ; Sepehrian, H ; Sharif University of Technology
Abstract
GAC has been modified by loading of potassium nickel hexacyanoferrate (KNiCF) as a new adsorbent for cesium adsorption. The potassium nickel hexacyanoferrate-loaded granular activated carbon (KNiCF-GAC) was characterized using powder x-ray diffraction (XRD) and nitrogen adsorption-desorption isotherm data, infrared spectroscopy, and its cesium adsorption performance in aqueous solution was investigated. The effect of the various parameters such as initial pH value of the solution, contact time, temperature, and initial concentration of the cesium ion on the adsorption efficiencies of KNiCF-GAC have been studied systematically by batch experiments. The adsorption isotherm of KNiCF-GAC was...
Investigation of the applicability of nano silica particles as a thickening additive for polymer solutions applied in EOR processes
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, Issue. 12 , 2014 , Pages 1315-1324 ; ISSN: 15567036 ; Kharrat, R ; Ghazanfari, M. H ; Sharif University of Technology
Abstract
In past decades, many attempts have been made to use water-soluble polymers as a mobility control agent to improve sweep efficiency of enhanced oil recovery processes. However, sensitivity of the thickening behavior of these polymers to some harsh conditions, such as high salinity, has cast serious doubt on their applicability in reservoir conditions. By expansion of nanotechnology, scientists discovered that nanoparticles can be utilized as thickening and rheology control agents in many polymer solutions. In this study, hydrophilic fumed silica is added to hydrolyzed polyacrylamide and sulfonated polyacrylamide solutions. The effect of the addition of nano silica on the thickening and...
Enhancement of efficient Ag-S/TiO2 nanophotocatalyst for photocatalytic degradation under visible light
, Article Industrial and Engineering Chemistry Research ; Vol. 53, issue. 23 , 2014 , Pages 9578-9586 ; ISSN: 08885885 ; Vossoughi, M ; Zakeri, S. M. E ; Rahimi, M ; Sharif University of Technology
Abstract
A new photocatalyst (Ag-S/PEG/TiO2) was synthesized by adding polyethylene glycol (PEG) to an efficient Ag-S/TiO2 photocatalyst, to obtain a photocatalyst that is highly active under visible light. In addition to Ag-S/PEG/TiO2, Ag-S/TiO2 and pure TiO2 were prepared to compare their properties and activities. Specifically, the morphologies and microstructures of the nanophotocatalysts were characterized by means of powder X-ray diffraction (XRD), N2 adsorption-desorption measurements, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) microanalysis, transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy,...
A core scale investigation of Asphaltene precipitation during simultaneous injection of oil and CO2: An experimental and simulation study
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, issue. 10 , Dec , 2014 , pp. 1077-1092 ; ISSN: 15567036 ; Rashtchian, D ; Ghazanfari, M. H ; Kharrat, R ; Sharif University of Technology
Abstract
Although CO2 injection significantly increases the amount of oil recovered, it can cause asphaltene deposition in oil reservoirs. Asphaltene deposition leads to formation damage, in which treatment is a costly and problematic operation. In this work, impact of asphaltene precipitation and deposition during CO2 injection are investigated for recombined oil both in sandstone and carbonate core samples through dynamic flow experiments. Injection of oil and CO2 was performed simultaneously. Then, pressure drops along the core were recorded continuously to estimate permeability reductions during the experiments. Online viscosity of injected fluid was measured by a designed capillary viscometer....
Modification of rock/fluid and fluid/fluid interfaces during MEOR processes, using two biosurfactant producing strains of Bacillus stearothermophilus SUCPM#14 and Enterobacter cloacae: A mechanistic study
, Article Colloids and Surfaces B: Biointerfaces ; Vol. 117 , May , 2014 , pp. 457-465 ; ISSN: 09277765 ; Zeinolabedini Hezave, A ; Mohammadi, S ; Niazi, A ; Ayatollahi, S ; Sharif University of Technology
Abstract
During any microbial enhanced oil recovery process, both cells and the metabolic products of bacteria govern the tertiary oil recovery efficiency. However, very accurate examination is needed to find the functionality of these tiny creatures at different reservoir conditions. In this regard, the effect of cell structure on ultimate microbial recovery efficiency which is the most dominant mechanism based on the microorganism types (gram-negative or gram-positive) was systematically investigated. At the first stage, possible different active mechanisms using Bacillus stearothermophilus SUCPM#14 strain were tested using specially designed injection protocol, in situ and ex situ core flooding...
Influence of β-lactoglobulin and its surfactant mixtures on velocity of the rising bubbles
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Vol. 460 , October , 2014 , pp. 361-368 ; ISSN: 09277757 ; Krzan, M ; Lotfi, M ; Dukhin, S. S ; Kovalchuk, V. I ; Javadi, A ; Gunes, D. Z ; Gehin-Delval, C ; Malysa, K ; Miller, R ; Sharif University of Technology
Abstract
The rising velocity of air bubbles in surfactant solutions is a sensitive measure for the formation of a dynamic adsorption layer (DAL) at the bubble surface. Due to a certain surface coverage by adsorbed species the bubble surface starts to become immobilized and the rising velocity is retarded. There is a large difference in the retardation effect in presence of the protein β-lactoglobulin (BLG) alone and its mixed solutions with surfactants. In presence of added surfactants BLG forms complexes, which adsorb and retard the bubble rising velocity according to their respective surface activity and adsorption kinetics. While the nonionic surfactant C12DMPO does not show significant increase...