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Deposition and Properties of ZIF-8/SiO2 Hydrophobi Anti-Corrosion Coating
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
In this research, a coating was created on the steel surface using the network structure of zeolite imidazolate-8 (ZIF-8) and its effect on the corrosion behavior of steel was investigated. Then, the effect of two coupling agents, mercaptopropyltriethoxysilane (MPTES) and aminopropyltriethoxysilane (APTES) on the coating and its anti-corrosion properties was investigated. Then, in order to make a hydrophobic coating, the substrate was first coated with ZIF-8 and then a combination of silica nanoparticles plus hexamethyldisilazane (HMDS) and polymethylhydrogensiloxane (PMHS) was added to the initial solution and then coating was done. As a result of this process, the contact angle of water...
Synthesis and Evaluation of Nanostructured ZIF-67-Based Electrocatalysts for Oxygen Evolution Reaction
, M.Sc. Thesis Sharif University of Technology ; Khorasheh, Farhad (Supervisor) ; Ghotbi, Sirus (Supervisor) ; Larimi, Afsaneh Sadat (Supervisor) ; Esmaeilpour, Mohsen (Co-Supervisor)
Abstract
Today, due to the decreasing of fossil fuel reserves and the need to use clean fuels, hydrogen is a suitable alternative, and hydrogen production has received considerable attention. One of the best methods of hydrogen production is water splitting. Overall water splitting can be divided into two half reactions including the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), which selecting the appropriate electrocatalyst for these half reactions plays an important role. The four-electron transfer process in OER leads to slow kinetics of the reaction and a large overpotential. The noble metal-based oxides, including IrO2 and RuO2, are known as outstanding OER...
Synthesis and Evaluation of Modified Zeolites for Separation of Acidic Gases
, M.Sc. Thesis Sharif University of Technology ; Khorasheh, Farhad (Supervisor) ; Soltanali, Saeed (Supervisor) ; Ghasabzadeh, Hamid (Co-Supervisor)
Abstract
The adsorption equilibria of carbon dioxide, methane, and nitrogen on pelletized cation-exchanged faujasite zeolite (with alkali, alkaline earth, and transition metal ions) have been investigated by a volumetric apparatus. The standard instrumental analytical techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) coupled with energy dispersive X-ray spectroscopy (EDX), and atomic absorption spectroscopy (AAS) were utilized to characterize binder-free modified zeolites. The EDX spectra and AAS results revealed that the ion-exchange was successfully achieved with expected tendencies. The results indicate that the type of cation present in the zeolite...
Fabrication of Nano-Structure Electrocatalysts for Use in Water Splitting Process
, M.Sc. Thesis Sharif University of Technology ; Ghotbi, Siroos (Supervisor) ; Khorasheh, Farhad (Supervisor) ; Asgharinezhad, Ali Akbar (Supervisor) ; Larimi, Afsaneh Sadat (Co-Supervisor)
Abstract
The global energy outlook has been altered as a result of mounting concerns regarding fossil fuels. Electrocatalysts have become a favorable alternative for renewable energy production processes, particularly in the fields of hydrogen evolution reactions (HER) and oxygen evolution (OER). This study focuses on the production and enhancement of nanocatalysts, specifically materials based on ZIF-67, for the purpose of water splitting. The initial phase included the synthesis of the ZIF-67 structure through the simple room-temperature coprecipitation process, utilizing cerium as a dual-metal component. The molarity of the cerium was optimized in the ZIF-67 framework to achieve the most desirable...
The joint reaction of methanol and i-butane over the HZSM-5 zeolite
, Article Journal of Industrial and Engineering Chemistry ; Volume 19, Issue 3 , May , 2013 , Pages 915-919 ; 1226086X (ISSN) ; Kazemeini, M ; Mohammadrezaee, A ; Golhosseini, R ; Sharif University of Technology
2013
Abstract
The effects of i-butane addition to methanol in MTP reaction were investigated over an in-house prepared HZSM-5 catalyst. It was observed that, propylene yield would be enhanced when i-butane fed to the reactor along with methanol. The rising growth of the propylene yield continued to peak on till the balance in thermal condition established. Similar trends have been observed when water was added to the mixture. The effect of WHSV with fixed water composition on product distribution was also studied. The optimum point where the highest amount of propylene yielded was shown to be high depended upon the temperature and residence time
Adsorption of xylene isomers on Na-BETA zeolite: Equilibrium in batch adsorber
, Article Microporous and Mesoporous Materials ; Volume 172 , 2013 , Pages 136-140 ; 13871811 (ISSN) ; Khademi, M ; Sharif University of Technology
2013
Abstract
In this article, adsorption of p-xylene, m-xylene, o-xylene, and ethylbenzene on Na-BETA type zeolite in liquid phase at 15, 25, and 35 °C has been studied and the single adsorption isotherms have been obtained and reported. The Langmuir isotherm model was used to describe the experimental adsorption isotherm data. It was found that p-xylene is more strongly adsorbed component followed by ethylbenzene, m-xylene and o-xylene. This means that this adsorbent is selective for p-xylene. Using Langmuir isotherm model, the saturation adsorption capacities of the adsorbent were obtained as follows 143 mg/g for p-xylene, 105 mg/g for ethylbenzene, 83 mg/g for m-xylene, and 68 mg/g for o-xylene at 25...
Enhanced visible light photocatalytic activity of nano-biocl/bivo4/zeolite p-n heterojunction and ag/biocl/bivo4 hybrid
, Article Materials Research Innovations ; 2016 , Pages 1-7 ; 14328917 (ISSN) ; Gholizadeh Khasevani, S ; Rahman Setayesh, S ; Gholami, M. R ; Sharif University of Technology
Taylor and Francis Ltd
2016
Abstract
Visible light-active BiOCl/BiVO4/mordenite and Ag/BiOCl/BiVO4 nanocomposite with a p–n heterojunction structure were prepared. Mordenite nanocrystals were synthesised using the hydrothermal method. Deposition and reduction methods were utilised to modify the Zeolite surface. The photocatalytic activities of the heterojunctions were investigated by scanning the change of Acid blue 92 (AB92) concentration under visible irradiation. The nanocomposites demonstrated improved efficiency for dye photodegradation. The activities are due to strong oxidative ability and efficient charge separation and transfer through the BiOCl/BiVO4 p–n junction. The photogenerated electron-holes react with species...
Synthesis of metal-organic framework hybrid nanocomposites based on GO and CNT with high adsorption capacity for dye removal
, Article Chemical Engineering Journal ; Volume 326 , 2017 , Pages 1145-1158 ; 13858947 (ISSN) ; Vossoughi, M ; Mahmoodi, N. M ; Alemzadeh, I ; Sharif University of Technology
Abstract
In this study, zeolitic imidazolate framework (ZIF-8) as a metal-organic framework (MOF) and its hybrid nanocomposites based on graphene oxide (GO) and carbon nanotubes (CNTs) were synthesized by facile method at an ambient temperature. The sufficiency of GO and CNT substrates as the main components of the composites to grow nanoscale MOFs and increase dispersive forces were investigated. The characteristics of the MOF and hybrid nanocomposites were studied using FTIR, SEM, XRD, BET and TGA techniques. The prepared nanomaterials applied as adsorbents to remove malachite green (MG) as a cationic dye from colored wastewater. The removal rates of the hybrid nanocomposites were greater than that...
Enhanced visible light photocatalytic activity of nano-BiOCl/BiVO4/Zeolite p-n heterojunction and Ag/BiOCl/BiVO4 hybrid
, Article Materials Research Innovations ; Volume 22, Issue 3 , 2018 , Pages 137-143 ; 14328917 (ISSN) ; Gholizadeh Khasevani, S ; Rahman Setayesh, S ; Gholami, M. R ; Sharif University of Technology
Taylor and Francis Ltd
2018
Abstract
Visible light-active BiOCl/BiVO4/mordenite and Ag/BiOCl/BiVO4 nanocomposite with a p–n heterojunction structure were prepared. Mordenite nanocrystals were synthesised using the hydrothermal method. Deposition and reduction methods were utilised to modify the Zeolite surface. The photocatalytic activities of the heterojunctions were investigated by scanning the change of Acid blue 92 (AB92) concentration under visible irradiation. The nanocomposites demonstrated improved efficiency for dye photodegradation. The activities are due to strong oxidative ability and efficient charge separation and transfer through the BiOCl/BiVO4 p–n junction. The photogenerated electron-holes react with species...
Applying the Taguchi method to develop an optimized synthesis procedure for nanocrystals of T-type zeolite
, Article Chemical Engineering and Technology ; Volume 32, Issue 7 , 2009 , Pages 1042-1048 ; 09307516 (ISSN) ; Bastani, D ; Kazemian, H ; Sharif University of Technology
2009
Abstract
The effects of H2O/SiO2, TMAOH/SiO2, Na/(Na+K), and SiO2/Al2O3 ratios in the parent gels on the crystallization of nanoparticles of T-type zeolites were studied. A Taguchi orthogonal experimental design with the above-mentioned parameters (each at three levels) was used to optimize the experiment parameters by the analysis of variances (ANOVA). Applying the Taguchi method significantly reduced the time and cost required for optimization. The synthesized products were characterized by X-ray diffraction and scanning electron microscopy. As a result of the Taguchi analysis, H2O/SiO2 and TMAOH/SiO2 were the most influencing parameters for the synthesis of zeolite T. © 2009 WILEY-VCH Verlag GmbH...
Mathematical model and energy analysis of ethane dehydration in two-layer packed-bed adsorption
, Article Particuology ; Volume 47 , 2019 , Pages 33-40 ; 16742001 (ISSN) ; Hosseini, S. H ; Ahmadi, G ; Olazar, M ; Sharif University of Technology
Elsevier B.V
2019
Abstract
The 3A zeolites are excellent adsorbents for industrial-scale gas dehydration because of the low energy required for regeneration and ease of operation. A computational study of the dehydration of an industrial feed stream containing ethane and water was performed using an in-house code that included an appropriate equilibrium adsorption isotherm. The validated computational model was used to examine the impact of particle size on the process dynamics and the corresponding pressure drop. The water concentration along the adsorption column was also investigated. To increase the process capacity, the packed adsorption bed was divided into two distinct layers, which were operated with different...
Converting waste cooking oil into biodiesel using phosphomolybdic acid/clinoptilolite as an innovative green catalyst via electrolysis procedure; optimization by response surface methodology (RSM)
, Article Fuel Processing Technology ; Volume 225 , 2022 ; 03783820 (ISSN) ; Tahvildari, K ; Hemmati, A ; Azar, P. A ; Safekordi, A ; Sharif University of Technology
Elsevier B.V
2022
Abstract
The present study aims to convert waste cooking oil (WCO) into biodiesel via phosphomolybdic acid (H3PMo12O40, PMA) supported on Clinoptilolite as a novel green acid catalyst through an electrolysis procedure. The prepared catalysts were characterized by XRD, FTIR, FESEM, EDS, Elemental map, and TEM analyses. The effect of four independent variables on biodiesel yield including methanol to oil molar ratio (6:1–14:1), catalyst weight (2–5 wt%), time (3–5 h), and voltage (15–35 V) was optimized and evaluated by the response surface methodology (RSM) employing central composite design (CCD). The maximum value of biodiesel yield was 96% under the optimal conditions, including the methanol to oil...
Removal of toxic heavy metal ions from waste water by functionalized magnetic core-zeolitic shell nanocomposites as adsorbents
, Article Environmental Science and Pollution Research ; Volume 20, Issue 6 , 2013 , Pages 3900-3909 ; 09441344 (ISSN) ; Gholami, M. R ; Sharif University of Technology
2013
Abstract
Functionalized magnetic core-zeolitic shell nanocomposites were prepared via hydrothermal and precipitation methods. The products were characterized by vibrating sample magnetometer, X-ray powder diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption-desorption isotherms, and transmission electron microscopy analysis. The growth of mordenite nanocrystals on the outer surface of silica-coated magnetic nanoparticles at the presence of organic templates was well approved. The removal performance and the selectivity of mixed metal ions (Pb2+ and Cd2+) in aqueous solution were investigated via the sorption process. The batch method was employed to study the sorption kinetic,...
Study of temperature and velocity distribution of rarefied gas flow in micro-nano channels
, Article Proceedings of the ASME Fluids Engineering Division Summer Conference 2009, FEDSM2009, 2 August 2009 through 6 August 2009, Vail, CO ; Volume 1, Issue PART B , 2009 , Pages 1045-1050 ; 9780791843727 (ISBN) ; Shams, A ; Ebrahimi, R ; Sharif University of Technology
Abstract
This paper deals with simulation of transport phenomena in micro and nano pores. The number of cavities and the cavity radius were estimated by using Henry's law for adsorption of Argon onto ZSM-5 and NaX zeolites. This work showed both of zeolites have pores with average size less than 1 nm. Then with using micro- nano channel assumption instead of micro-nano pores, gas flow and heat transfer were investigated. Subsonic nonideal gas flow and heat transfer for different Knudsen number are investigated numerically using the Direct Simulation Monte Carlo method modified with a consistent Boltzamnn algorithm. The collision rate is also modified based on the Enskog theory for dense gas. It is...
Mass transfer through PDMS/zeolite 4A MMMs for hydrogen separation: Molecular dynamics and grand canonical Monte Carlo simulations
, Article International Communications in Heat and Mass Transfer ; Volume 108 , 2019 ; 07351933 (ISSN) ; Amirkhani, F ; Khadem, S. A ; Rezakazemi, M ; Asghari, M ; Shirazian, S ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In industry, utilizing membrane separation technology to purify natural gas streams is of remarkable significance. Molecular Simulation was used in the current article to study the structural and gas separation properties of polydimethylsiloxane (PDMS)/zeolite 4A Mixed Matrix Membranes (MMMs). To explore the optimal performance of MMMs, several structural analyses, namely Fractional Free Volume (FFV), Radial Distribution Function (RDF), X-Ray Diffraction (XRD) and also Glass Transition Temperature (Tg) as one of the most important properties of membranes have been evaluated. Also, the solubilities and diffusivities of periodic cells were respectively measured using MSD and adsorption...
Synthesis of dimethyl ether over modified H-mordenite zeolites and bifunctional catalysts composed of Cu/ZnO/ZrO2 and modified H-mordenite zeolite in slurry phase
, Article Catalysis Letters ; Volume 129, Issue 1-2 , 2009 , Pages 111-118 ; 1011372X (ISSN) ; Kazemeini, M ; Aghaziarati, M ; Sharif University of Technology
2009
Abstract
Synthesis of dimethyl ether (DME) via methanol dehydration were investigated over various catalysts, and via direct CO hydrogenation over hybrid catalysts composed of Al-modified H-Mordenite zeolite and Cu/ZnO/ZrO 2. H-Mordenite zeolite exhibited the highest activity in dehydration of methanol. However, its selectivity toward dimethyl ether was rather low. For this reason, the H-Mordenite was modified. Modification of zeolites was performed by wet impregnation method and considered catalysts were characterized by AAS, XRD and NH3-TPD analyses. Results of catalytic tests indicated that H-Mordenite modified with 8 wt% aluminum oxide was the best catalyst for synthesis of dimethyl ether from...
Laser irradiation for controlling size of TiO2-Zeolite nanocomposite in removal of 2,4-dichlorophenoxyacetic acid herbicide
, Article Water Science and Technology ; Volume 80, Issue 5 , 2019 , Pages 864-873 ; 02731223 (ISSN) ; Borghei, S. M ; Moniri, E ; Kimiagar, S ; Panahi, H. A ; Sharif University of Technology
IWA Publishing
2019
Abstract
This study focused on the synthesis of TiO2-Zeolite nanocomposite through a sol-gel approach. The decrease in the size of the nanocomposite is considered a primary parameter to improve photocatalytic activity. In this regard, fabricated samples were exposed to laser irradiation (532 nm) for four different time intervals in order to investigate the size variation of the nanocomposite. FTIR, UV-Vis, XRD, DLS, SEM and EDX analyses were applied to characterize and determine the size of the products. An optimized nanocomposite sample, in term of the particle size, was used for photodegradation of 2,4-D herbicide from aqueous solution. Photodegradation was carried out under UV irradiation (12 W)...
Mixed Matrix Membrane Preparation for Gas Separation
, M.Sc. Thesis Sharif University of Technology ; Soltanieh, Mohammad (Supervisor) ; Mousavi, Abbas (Supervisor)
Abstract
This study has concentrated on preparation of mixed matrix membranes (MMMs) in order to improve the separation performance of the neat poly(amide-12-b-ethylene oxide)(Pebax1074) membrane. Pebax1074 and zeolite SAPO-34 were used to fabricate MMM for the first time. Micro-size SAPO-34 was added to polymer matrix up to 35wt% based on polymer weight; even though at this high loading percentage the prepared membranes were not stable enough to be tested for characterization and gas permeation. The obtained results showed more than 30% increment in CO2 permeability, along with slight growth and reduction in N2 and CH4 permeabilities, respectively for 30wt% zeolite content membranes. Permeability...
Fabrication of granulated NaY zeolite nanoparticles using a new method and study the adsorption properties
, Article Powder Technology ; Volume 231 , November , 2012 , Pages 1-6 ; 00325910 (ISSN) ; Kazemeini, M ; Ahmadi, S. J ; Kazemian, H ; Sharif University of Technology
2012
Abstract
NaY zeolite nanoparticles were synthesized and shaped into the uniform spherical granules using a developed novel and simple two-step granulation technique. First, the alginate/nanozeolite or alginate/nanozeolite-bentonite spherical hybrid was successfully fabricated, and then the alginate was decomposed by calcinations resulting uniform spherical granules. To improve the mechanical stability of the prepared granules, bentonite was added as an inorganic binder at different ratios of 20wt.% to 40wt.%. Moreover, the effect of binder on the ion exchange properties of the prepared granules was studied. Increasing of binder content from 20wt.% to 40wt.% linearly enhanced the mechanical stability...
Adsorption and diffusion of Xenon in a granulated nano-NaY zeolite
, Article Adsorption ; Volume 18, Issue 2 , 2012 , Pages 75-86 ; 09295607 (ISSN) ; Kazemeini, M ; Ahmadi, S. J ; Allahyar, S. A ; Sharif University of Technology
Springer
2012
Abstract
Henry's law constant and crystal diffusivity of xenon in the granulated nano-NaY zeolite were measured by the pulse gas chromatography method. For this purpose the moments of response peaks of xenon were analyzed. The effect of extra column parts of the utilized chromatographic system was also considered by analyzing the moments of the response peak which was obtained by pulse injection of inert gas of helium into the carrier gas of nitrogen. In addition, the measurement of average velocity of the carrier gas regarding the pressure drop in the extra column parts of the system attributed to precise results. By carrying out the experiments at various temperatures in the range of 30-110 °C the...