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Oxidation of Sulfides and Olefins in the Presence of Nanocluster Polyoxotungstate–intercalated Layered Double Hydroxide Nanoparticles as a Catalyst
, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
In this study, polyoxometalate (POM) intercalated in the layered double hydroxide (LDH) was synthesized by a selective ion-exchange method. For this purpose, the nanocluster [VW12O40]3- was immobilized on the Mg2+/A13+/Cl–LDH support. The heterogeneous catalyst was characterized by FT-IR, XRD, SEM and analysis of ICP. The LDH-POM was applied as a catalyst in efficient oxidation of sulfides to sulfoxides using UHP as oxidant and CH3OH/ CH¬2¬Cl¬2 ¬as a solvent at room temperature, as well as epoxidation of olefins using TBHP as an oxidants and C¬2H4Cl2 as a solvent in 84°C. This catalyst showed excellent catalytic activities for a substrate/catalyst ratio (200:1). For example, this catalytic...
Synthesis and characterization of a bentonite-alginate microspherical adsorbent for removal of uranyl ions from aqueous Solutions
, Article Separation Science and Technology ; Volume 45, Issue 2 , 2010 , Pages 288-298 ; 01496395 (ISSN) ; Khanchi, A ; Ghofrani, M.B ; Outokesh, M ; Sharif University of Technogy
2010
Abstract
A novel microspherical adsorbent for the removal of uranium from aqueous solutions was developed by immobilizing of natural bentonite in the polymeric matrix of calcium alginate. Different uptake properties of the prepared microspheres were examined using batch, stirred and column methods. The adsorbent showed high affinity toward uranium ions, especially at pHs above 3. Major uptake mechanisms included ion exchange, chelating of the (UO2)2+ ions to the -OH groups of alginate, and surface complexation with bentonite. Surprisingly, the capacity of microspheres was higher than both its constituents, revealing that a synergetic effect occurs. Adsorption kinetics was controlled by slow chemical...
Influence of annealing on the electrochemical behavior of finemet amorphous and nanocrystalline alloy
, Article Journal of Materials Science ; Volume 45, Issue 2 , 2010 , Pages 546-551 ; 00222461 (ISSN) ; Nozad Golikand, A ; Madaah Hosseini, H. R ; Asgari, M ; Sharif University of Technology
Abstract
The electrochemical corrosion behavior of finemet alloy at various heat treatment temperatures was investigated. Thermal behavior and structural changes were studied using differential scanning calorimetry and X-ray diffractometry, respectively. The electrochemical corrosion of amorphous and annealed samples was investigated in 0.10 M NaOH solution using electrochemical impedance spectroscopy and linear sweep voltammetery. Changes in morphology of the samples before and after corrosion were characterized using optical microscope. The results showed that structural relaxation and nanocrystallization during the heat treatment improved corrosion behavior of the alloy. The heat-treated alloy at...
Impact of sulfate ions on wettability alteration of oil-wet calcite in the absence and presence of cationic surfactant
, Article Energy and Fuels ; Volume 30, Issue 2 , 2016 , Pages 819-829 ; 08870624 (ISSN) ; Al-Maamari, R. S ; Ayatollahi, S ; Mehranbod, N ; Sharif University of Technology
American Chemical Society
2016
Abstract
The modification of the surface wetting characteristics in fractured oil-wet carbonate reservoirs, by reversing wettability from oil-wet to water-wet, leads to improved oil recovery. However, in order to obtain a successful oil recovery process, it is crucial to understand the active mechanisms of wettability alteration. This study looks at the effect of sulfate ions as one of the most promising wettability influencing ions on the wetting properties of oil-wet calcite; the effect is studied both with and without the presence of cationic surfactant and possible mechanisms of wettability alteration are explored. A number of analytical techniques were utilized to analyze the mineral surface...
Adsorptive behavior of an amberlite anion exchanger resin for uranium (VI) sorption in the presence of sulfate anions
, Article International Journal of Engineering, Transactions B: Applications ; Volume 29, Issue 2 , 2016 , Pages 170-175 ; 1728144X (ISSN) ; Sepehrian, H ; Fasihi, J ; Arabieh, M ; Mahani, M ; Sharif University of Technology
Materials and Energy Research Center
Abstract
Uranium (VI) sorption using an anionic exchanger resin, namely Amberlite IRA910, in the presence of sulfate anions was the subject of current study. Batch sorption experiments were carried out to evaluate the influence of operational parameters such as pH, contact time, initial concentration and existence of various anions (including phosphate, sulfate, chloride, fluoride, and nitrate) in the solution on Amberlite IRA910 sorption behavior. Experiments revealed that uranium adsorption was fulfiled at pH>3 and 50 min to amount of 80%. Kinetics study revealed that the pseudo-second-order model showed better curve-fitting regression of the experimental data than the pseudo-first-order one....
Effect of casting solvent on the characteristics of nafion/TiO2 nanocomposite membranes for microbial fuel cell application
, Article International Journal of Hydrogen Energy ; Volume 41, Issue 1 , 2016 , Pages 476-482 ; 03603199 (ISSN) ; Mousavi, S. A ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
Synthesis and characterization of Nafion/TiO2 membranes (TiO2 1 wt%) with different solvents (DMF, DMAc, NMP) for proton exchange membrane operating at Microbial Fuel Cell (MFC) was investigated in this study. Nanocomposite membranes are studied due to their better physical properties and higher production voltage in comparison with Nafion 112 in MFC systems. Nafion/TiO2 nanocomposite membranes were prepared by solution casting Method. The structures of membranes were investigated by Scanning Electron Microscopy (SEM). In addition, water uptake, proton conductivity, and ion exchange capacity (IEC) of membranes were measured and compared with Nafion 112 in microbial fuel cell. The...
Experimental Study and Optimization of Nuclear Grade Boric Acid Production Process
, M.Sc. Thesis Sharif University of Technology ; Outokesh, Mohammad (Supervisor) ; Aflaki Pashaki, Fereydoon (Supervisor)
Abstract
Boric acid (H3BO3) is a weak monobasic acid that exist as a white powder in the standard conditions. In industry, it is used in manufacturing of fiberglas filaments, precious metals soldering and production of flat panel LCD displays. In all of these applications, normal grade boric acid is used, but nuclear industry demands an ultrapure boric acid (UPA) for controlling of the reactivity and power levels in pressurized water reactors. Annual consumption of UPA in Bushehr Power Plant (BPP) is around 60 metric tons. Currently, this amount is imported from Russia, but atomic energy organization of Iran plans to displace it by the acid made inside the country. Domestic production of UPA in...
Study on Separation of Uranium from Phosphoric Acid by Column Chromatography
, M.Sc. Thesis Sharif University of Technology ; Sohrabpour, Mostafa (Supervisor) ; Khanchi, Ali Reza (Supervisor) ; Outokesh, Mohammad (Supervisor)
Abstract
In this study, uranium removal from phosphoric acid with doulite resin was examined. Different uptake properties of the doulite resin were examined using batch, stirred and column methods. Langmuier, freundlich and dubinin equation was fitted the isotherm data and freundlich equation showed the best fitting. Adsorption kinetics was controlled by slow intraparticle diffusion of UO22+ ions in resin, and it obeyed a shrinking core model. Also a pseudo-second order chemical reaction fairly fitted the kinetics data
Synthesis parameters effect on the final morphology of the layered double hydroxide (LDH)
, Article Protection of Metals and Physical Chemistry of Surfaces ; Volume 53, Issue 3 , 2017 , Pages 460-465 ; 20702051 (ISSN) ; Afshar, A ; Sharif University of Technology
Maik Nauka Publishing / Springer SBM
2017
Abstract
Smart coatings which prevent corrosion by several mechanisms recently have been carefully planned. One of these mechanisms is the use of ion exchangers like LDH in the coating network. Since the morphology is the most important properties for the applications that the surface plays an important role, LDH morphology was evaluated in this study. For this purpose, the LDH contain a kind of green inhibitor was synthesized and after evaluating its performance it was examined morphologically by changing significant parameters like MII/MIII, pH, aging time and temperature. It is found that, high ratio of the MII/MIII cause thinner layer of LDH. The pH also has special effect on the surface...
Immobilization of Spent Ion Exchange Resins from Bushehr Nuclear Power Plant
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Davarkhah, Reza (Supervisor) ; Tavasoli, Maryam (Co-Advisor)
Abstract
Ion exchange resins are widely used in nuclear industries. These spent resins result in the production of a large amount of low and intermediate level radioactive wastes, therefore, the treatment and immobilization of spent ion exchange resins are the major problems in the development of nuclear power plants.In this research, in a laboratory scale, we tried to find the suitable procedure and formulation to immobilize a specific group of cation-exchange resins which is used in Bushehr nuclear power plant (AMBERLITE IRN-97H) in the cement matrix. The solidification matrix consists of five constituents: anti sulfate slag type portland cement, cation-exchange resins, diatomite, sodium hydroxide...
Bi-amino surface functionalized nanoparticles: Synthesis and binary system dye removal from wastewater containing anionic dyes
, Article Desalination and Water Treatment ; Volume 70 , 2017 , Pages 347-354 ; 19443994 (ISSN) ; Ghezelbash, M ; Ghotbei, C ; Kazemeini, M ; Sharif University of Technology
Desalination Publications
2017
Abstract
In this paper, copper oxide nanoparticle was synthesized, and its surface was modified using N-(2-aminoethyl)-3-(trimethoxysilyl)propylamine. The bi-amino surface functionalized nanoparticle (BASFN) was used to remove anionic dyes from single and binary systems. The scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDAX) and X-ray diffraction were used to characterize the nanoparticle. Direct Red 80 (DR80) and Direct Green 6 (DG6) were used as anionic dyes. The effect of adsorbent dosage, dye concentration and pH on dye removal was evaluated. Kinetic of dye adsorption on BASFN followed pseudo-second order. The results...
Streaming potential measurement to quantify wetting state of rocks for water based EOR, inhouse novel setup experience
, Article IOR NORWAY 2017 - 19th European Symposium on Improved Oil Recovery: Sustainable IOR in a Low Oil Price World, 24 April 2017 through 27 April 2017 ; 2017 ; 9789462822092 (ISBN) ; Jafarlou, A ; Nejadali, M ; Esmaeili, S ; Pahlavanzadeh, H ; Ayatollahi, S ; Sharif University of Technology
Abstract
The wetting condition of the reservoir rock is the key to the success of any EOR technique and the ultimate oil recovery. Wettability is dictated by the surface chemistry related to the interactions between the fluids and the rock surface which determines the stability of the water film between the rock and the oil phase. Streaming potential measurement is one of the electrokinetic techniques used to determine the average zeta potential of porous rock which can provide reliable information on fluid-rock interaction and wettability state of the rock surface. Streaming potential measurement has recently been introduced in the oil reservoirs applications and there are still significant...
Ion-pair extraction-reaction of calcium using Y-shaped microfluidic junctions: An optimized separation approach
, Article Chemical Engineering Journal ; Volume 334 , 2018 , Pages 2603-2615 ; 13858947 (ISSN) ; Karimi Sabet, J ; Amini, Y ; Sharif University of Technology
Elsevier B.V
2018
Abstract
In this research, a continuous microsolvent extraction-reaction was developed for the efficient separation of calcium ion. This study gives a preliminary possible practical application of microfluidic devices in chemical exchange reaction for enrichment of 48Ca stable isotope. For this purpose, in the first stage, the hydrodynamic behavior of two immiscible liquids in a simple Y-shaped microfluidic junction is experimentally investigated, and then ion-pair extraction-reaction of Ca2+ using picric acid as a counter-ion and dicyclohexano-18-crown-6 (DC18C6) as a lipophilic ionophore is studied in this microfluidic and conventional batch method. The impact of main process parameters, including...
Synthesis of Na-A and faujasitic zeolites from high silicon fly ash
, Article Materials Research Bulletin ; Volume 44, Issue 4 , 2009 , Pages 913-917 ; 00255408 (ISSN) ; Kazemian, H ; Kazemeini, M ; Sharif University of Technology
2009
Abstract
High silicon fly ash (HSFA) utilized as a source of silicon in synthesizing of Na-A, -X and -Y zeolites through alkali fusion followed by hydrothermal treatment at 100 °C for 12 h. Various types of zeolites with different degrees of purity were prepared by changing Si/Al ratio of the reaction mixture from 1.6 to 3.0. In addition, exact boundaries of this ratio for synthesis of each zeolite type were determined. Furthermore, the effect of NaOH amount utilized in alkaline fusion step on crystalinity of samples investigated. The synthesized zeolites were characterized using various techniques including; XRD, TGA, FTIR, SEM and BET. The ion-exchange behaviors of zeolitic samples tested with...
Study on modification of colloidal silica surface with magnesium ions
, Article Journal of Colloid and Interface Science ; 2009 , Pages 379-383 ; 00219797 (ISSN) ; Sharif University of Technology
2009
Abstract
The prepared colloidal silica via ion exchange was modified by adding Mg+2 ions in the surface growth process of colloidal silica. The particle size of the modified colloidal silica was decreased by increasing the seed concentration, whereas that of colloidal silica was slightly increased as the seeds concentration exceed 15 wt%. But the trend of changes in surface area was completely reversed. Magnesium ions on surface of the modified colloidal silica were identified by the measurement of energy-dispersive X-ray spectrometry (EDS). After modifying with Mg+2 ions, the iso-electric point (IEP) of colloidal silica in pH ∼ 2 without modification, disappears over the whole pH range. © 2008...
Electrochemical impedance studies of methanol oxidation on GC/Ni and GC/NiCu electrode
, Article International Journal of Hydrogen Energy ; Volume 34, Issue 2 , 2009 , Pages 859-869 ; 03603199 (ISSN) ; Jafarian, M ; Forouzandeh, F ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
2009
Abstract
The electro-oxidation of methanol on nickel and nickel-copper alloy modified glassy carbon electrodes (GC/Ni and GC/NiCu) in a 1 M NaOH solution at different concentrations of methanol was studied by the method of ac-impedance spectroscopy. Two semicircles in the first quadrant of a Nyquist diagram were observed for electro-oxidation of methanol on GC/Ni corresponding to charge transfer resistance and adsorption of intermediates. Electro-oxidation of methanol on GC/NiCu shows negative resistance in impedance plots as signified by semi-circles terminating in the second quadrant. The impedance behavior shows different patterns at different applied anodic potential. The influence of the...
Lithium Extraction with TiO2 Nanotube Synthesized by Anodizing Method
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor)
Abstract
Due to the technology advancement and the large-scale application of lithium-ion batteries in recent years, the market demand for lithium is growing rapidly and the availability of land lithium resources is decreasing significantly. As such, the focus of lithium extraction technologies has shifted to water lithium resources involving salt-lake brines and sea water. The ion exchange process is a promising method for lithium extraction from brine and seawater having low concentrations of this element. Among various aqueous recovery technologies, the lithium ion-sieve (LIS) technology is considered the most promising one. This is because LISs are excellent adsorbents with high lithium uptake...
Preparation of Polymeric Ion-Exchange Membrane for Water Desalination
, M.Sc. Thesis Sharif University of Technology ; Musavi, Abbas (Supervisor)
Abstract
In present research work, methods of preparing ion exchange membranes, especially anion exchange membranes, were studied and chemical modification of polysulfone was chosen as a safe and economical method for preparing anion exchange membranes. The chloromethylated polysulfone was characterized by HNMR spectroscopy and functionalization degree was determined according to peak area integration. Membranes were produced by mixing and amination of the chloromethylated and normal polysulfone (40-100% wt). Morphology and chemical structure of membranes were investigated by SEM images and FTIR spectroscopy.The ionic conductivity, ion exchange capacity and water content of samples were measured. The...
Mechanism of deleading of silicate glass by 0.5 N HNO3
, Article Journal of Non-Crystalline Solids ; Volume 355, Issue 48-49 , 2009 , Pages 2400-2404 ; 00223093 (ISSN) ; Rahimi, R. A ; Raisali, G ; Foruzanfar, F ; Sharif University of Technology
2009
Abstract
Mechanism of removal of lead from silicate glass containing 68.5 wt% PbO by 0.5 N HNO3 was investigated by incorporation of the chemical-analyses/weight-loss data into shrinking-core model (SCM) and minimization of the difference. Scanning electron microscopy (SEM), emission spectrometry with inductively coupled plasma (ICP), X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDS) were used to determine the compositional changes of the lead-silicate glass (LSG) samples. Dual inter-diffusion chemical reaction mechanisms having respective activation energies of 83.49 and 47.80 kJ/mol dominated the deleading process. © 2009 Elsevier B.V. All rights reserved
Selective Adsorption of Li+Ion on Lithium Adsorbents
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor)
Abstract
Interest in lithium sources has been increasing because of wide applications of the metal in high-energystorage lithium batteries and its compounds in otherfields.Lithium appears in lake, brines and several minerals such as spodumene, petallite, and lepidolite. Several methods such as ion exchange (adsorption), solvent extraction, and coprecipitation have been investigated for the extraction of lithium from seawater, brine, and geothermal water. The adsorption method is suitable for recovery of lithium from seawater because certain inorganicion-exchange materials show extremely high selectivity for lithium ions only.The objective of this study is to evaluate the applicability of nano...