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Total 55 records

    , M.Sc. Thesis Sharif University of Technology Sarrafan, Kiana (Author) ; Bastani, Daruoosh (Supervisor)
    Abstract
    In liquid-liquid extraction, as in gas absorption, two phases must be brought into good contact to permit transfer of material. The presence of nanoparticles in liquid phase can enhanced the rate of gas-liquid mass transfer. The benefits of nanofluids can be used to enhance the heat and mass transfer of liquid-liquid extraction. Standard test system with low interfacial tension that recommended by EFCE: n-butanol/water/succinic acid, was used in this project. The CNTs/n-butanol that was saturated of water used as dispersed phase. Water and succinic acid used as continuous phase and solute. Since there is no chemical reaction to take place between CNTs and n-butanol, In order to obtain well... 

    Tantalum electrodes modified with well-aligned carbon nanotube-au nanoparticles: application to the highly sensitive electrochemical determination of cefazolin

    , Article Applied Biochemistry and Biotechnology ; Volume 173, Issue 6 , July 2014 , Pages 1511-1528 Fayazfar, H ; Afshar, A ; Dolati, A ; Sharif University of Technology
    Abstract
    Carbon nanotube/nanoparticle hybrid materials have been proven to exhibit high electrocatalytic activity suggesting broad potential applications in the field of electroanalysis. For the first time, modification of Ta electrode with aligned multi-walled carbon nanotubes/Au nanoparticles introduced for the sensitive determination of the antibiotic drug, cefazolin (CFZ). The electrochemical response characteristics of the modified electrode toward CFZ were investigated by means of cyclic and linear sweep voltammetry. The modified electrode showed an efficient catalytic activity for the reduction of CFZ, leading to a remarkable decrease in reduction overpotential and a significant increase of... 

    Surface modification of glassy carbon electrode with the functionalized carbon nanotube for ultrasensitive electrochemical detection of risperidone

    , Article Journal of the Iranian Chemical Society ; Volume 15, Issue 7 , July , 2018 , Pages 1485-1494 ; 1735207X (ISSN) Shahrokhian, S ; Hafezi Kahnamoui, M ; Salimian, R ; Sharif University of Technology
    Springer Verlag  2018
    Abstract
    Risperidone (RIS), one of the typical antipsychotics drugs, originally approved to be used for the mental illness treatment, especially schizophrenia, bipolar disorder, autism and major depression. In the present study, different carbon nanostructures including functionalized multi-walled carbon nanotubes (F-MWCNTs), carbon nanoparticles, nanodiamond-graphite and reduced graphene oxide were employed for modification of the surface of glassy carbon electrode (GCE) for ultrasensitive detection of RIS. The most significant increase in the anodic peak current of RIS was observed on F-MWCNTs-modified electrode (compared to the other modified electrodes and bare GCE). The influence of different... 

    Multi-walled carbon nanotube paste electrode for selective voltammetric detection of isoniazid

    , Article Microchimica Acta ; Volume 157, Issue 3-4 , 2007 , Pages 149-158 ; 00263672 (ISSN) Shahrokhian, S ; Amiri, M ; Sharif University of Technology
    2007
    Abstract
    A multi-walled carbon nanotube paste electrode (MWCPE) is prepared as an electrochemical sensor with high sensitivity and selectivity in responding to isoniazid. The electrochemical oxidation of isoniazid is investigated in buffered solution by cyclic and differential pulse voltammetry. The electrode is shown to be very effective for the detection of isoniazid in the presence of other biological reductant compounds. The electrochemical oxidation of cysteine, due to the high overvoltage, is completely stopped at the surface of MWCPE. The electrode exhibits a very good resolution between the voltammetric peak of isoniazid and the peaks of ascorbic acid (AA) and dopamine (DA). A resolution of... 

    Adsorptive performance of MWCNTs for simultaneous cationic and anionic dyes removal; kinetics, thermodynamics, and isotherm study

    , Article Turkish Journal of Chemistry ; Volume 45, Issue 4 , 2021 , Pages 1189-1200 ; 13000527 (ISSN) Aslam, Z ; Yousaf, I ; Akhtar, A ; Zahi, A ; Sharif University of Technology
    TUBITAK  2021
    Abstract
    Disposal of contaminated wastewater causes many serious problems especially when it gets mixed with the ground and seawater. It is, therefore, important to apply any remedial action to eradicate dangerous pollutants from the aqueous effluents and to avoid exposure of this wastewater to aquatic life. The research results discussed herein deal with the removal of Rhodamine B (RhB) and Congo Red (CR) dye from wastewater by using multi-walled carbon nanotubes (MWCNTs) as an adsorbent. Different factors like solid dosage, initial pH and concentration, time, and temperature were studied to understand the behavior and mechanism of adsorption. The maximum adsorption capacity in case of a single... 

    An Investigation on Physical and Photochemical Properties of Sol-Gel Derived MWCNT-WO3 Nanocomposite thin Films

    , M.Sc. Thesis Sharif University of Technology Yousefzadeh, Samira (Author) ; Moshfegh, Alireza (Supervisor)
    Abstract
    WO3 have good electrochromic, gas sensor, photocatalyst, phoelectrochemical (PEC) properties. due its properties, tungsten oxide have many application in technology and industry. In this thesis, pure WO3 thin film and MWCNT-WO3 nanocomposite thin films with different weight percent of MWCNT/WO3 utilize for energy domain, particular hydrogen production with phoelectrochemical reactions spiliting water. For this purpose, initially WO3 thin films were deposited on glass and ITO substrates using sol-gel dip-coating method. Optical and surface properties of the films dried at 100ºC and annealed at 400 ºC had been investigated. UV-Visible spectrophotometer, atomic force microscopy (AFM), X-ray... 

    Carbon-based nanocomposites: Distinguishing between deep-bed filtration and external filter cake by coupling core-scale mud-flow tests with computed tomography imaging

    , Article Journal of Natural Gas Science and Engineering ; Volume 105 , 2022 ; 18755100 (ISSN) Heydarzadeh Darzi, H ; Fouji, M ; Ghorbani Heidarabad, R ; Aghaei, H ; Hajiabadi, S. H ; Bedrikovetsky, P ; Mahani, H ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    Although Multi-Walled Carbon NanoTubes (MWCNTs) are found to influence the rheological behavior of drilling fluids, there are yet some controversies regarding their performance towards reducing formation damage induced by the invasion of water-based drilling fluids (WBFs). To address this important question, we synthesized novel nanocomposite materials via modifying the MWCNT via varying the proportion of carboxylated MWCNTs to PolyVinyl Alcohol (PVA). These nanocomposites were then used to make nano-based drilling-fluids (NDFs). The performance of the NDFs was evaluated by a set of rheological behavior tests, filtration experiments, and core-scale mud flow tests. To distinguish between the... 

    Pharmaceutical Active Compounds Removal by Immobilized Laccase on the Membrane

    , M.Sc. Thesis Sharif University of Technology Golgoli, Mitra (Author) ; Borghei, Mehdi (Supervisor) ; Ghobadi Nejad, Zahra (Co-Supervisor)
    Abstract
    Pharmaceutical active compounds existence in the water would cause serious ecological risks and human health-related adverse effects which turn to environmental concern, therefore several studies have done to remove pharmaceutical active compounds efficiently. Carbamazepine (CBZ), a widely used psychiatric drug, is one of the most frequently detected compounds in the surface water and groundwater which is studies in the current study. Recently, biocatalytic degradation using ligninolytic enzymes such as laccase provides a promising approach for their removal from water and wastewater. In this work, carbamazepine removal by immobilized laccase on modified membrane by multi wall carbon nanotube... 

    , M.Sc. Thesis Sharif University of Technology Mahdavi Shakib, Akbar (Author) ; Shahrokhian, Saeed (Supervisor)
    Abstract

    This experimental work is of two parts. First, self-assembled monolayers of cysteamine was formed on the gold electrode surface which leaded to the formation of amine groups on the surface; then amine bond was formed between these amine groups and the carboxylic acid groups of acid treated multi-walled carbon nanotubes (MWCNTs). The modified electrode was used for voltammetric determination of dopamine in the presence of uric acid. In the second part, acid treated MWCNTs were decorated with ruthenium nanoparticles; then the resulting composite was used for surface modification with the exact same procedure as the first part. Ruthenium nanoparticles on the electrode surface were... 

    Photodegradation of Chemical Pollutants Under UV Light by the Improved TiO2/CNT Nano Photocatalyst Coated on a Porous Substrate

    , M.Sc. Thesis Sharif University of Technology Kordhaghi, Fatemeh (Author) ; Sadrnezhaad, Khatiboleslam (Supervisor)
    Abstract
    In recent years, semiconductor photocatalysts have attracted much attention because of cleanliness, no secondary pollution and profound oxidation and reduction reactions at room temperature. TiO2 is recognized as the best semiconductor photocatalyst due to its higher photocatalytic activity, nontoxicity, electronic and optical properties, chemical stability and low cost. There are some problems preventing from wide application of titania such as rapid recombination of photogenerated electrons and holes, the lack of visible-light utilization and difficult recovery of photocatalyst. In this study, to overcome these problems, TiO2/MWCNTs nanocomposite was prepared. Carbon nanotubes are... 

    Preparation of Nano Fluid from Carbon Nanostructures to Enhance Heat Transfer in Cooling Towers

    , M.Sc. Thesis Sharif University of Technology Askari, Saeed (Author) ; Syfkordi, Ali Akbar (Supervisor) ; Lotfi, Roghayeh (Supervisor)
    Abstract
    In this paper, carbon structures such as multi wall carbon nano tubes, graphene and hybrid graphene-iron oxide, for utilisation in wet cooling towers in order to improve heat transfer are being discussed. All synthesized nanoparticles are prepared by chemical vapour deposition and wet chemical methods. Nature and structure of the created particles is also being examined by using X-Ray diffraction, transmission electron microscope and scanning electron microscope. The water used in this research is a kind of brine water, currently being used in industrial cooling towers at oil-rich regions of southern Iran. Performing the ICP test on the available water and by exact determination of its... 

    A study on the cementitious mortars containing multi-walled carbon nanotubes and nanographene

    , Article Journal of Testing and Evaluation ; Volume 51, Issue 2 , 2022 ; 00903973 (ISSN) Pachideh, G ; Toufigh, V ; Sharif University of Technology
    ASTM International  2022
    Abstract
    In this paper, the effects of the multi-walled carbon nanotubes (MWCNTs) and nanographene (GP) on the mechanical performance of the cementitious mortars were investigated in different environments. Six mix designs were fabricated by considering the previous studies and exposed to potable water, acidic, and alkaline environments. The GP and MWCNTs partially replaced the cement with 0.25 %, 0.5 %, and 1 % of its weight. The standard mechanical tests, X-ray diffraction (XRD), and scanning electron microscope (SEM) analysis were performed on the specimens. The results indicated that including the MWCNTs and GP increases the compressive strength by 10 % and 20 % and similarly improves the tensile... 

    Removal of Pharmaceuticals from Polluted Water Using Carbon Nanotube-based Membranes Coated with Enzyme

    , M.Sc. Thesis Sharif University of Technology Masjoudi, Mahsa (Author) ; Borghei, Mehdi (Supervisor) ; Ghobadi Nejad, Zahra (Co-Supervisor)
    Abstract
    Today, presence of micropollutants, including pharmaceutical compounds, in aquatic systems has turned into a major environmental challenge threatening the health of humans and many aquatic and terrestrial organisms. In the recent years, biodegradation of pharmaceuticals using enzymes, such as laccase, has been presented as a green method for eliminating these types of pollutants. Furthermore, regarding the improved stability and reusability of immobilized enzymes, these types of biocatalysts are suitable for industrial applications. Enzymatic membrane reactor is a promising method of enzymatic treatment and fabrication of a high-efficiency enzymatic membrane is a major step to begin this... 

    Investigation on Parameters of Carbon Nanotubes Growth and Effect of Interaction between H2 Gas and their Surfaces and Determining Capacity of Hydrogen Storage

    , Ph.D. Dissertation Sharif University of Technology Reyhani, Ali (Author) ; Moshfegh, Alireza (Supervisor) ; Nozad, Ahmad (Supervisor)
    Abstract
    In this study, growth of MWCNTs in form of thin film and powder for hydrogen storage was investigated. Different analytical techniques including SEM, TEM, STA, XRD, XPS, BET, BJH and Raman spectroscopy were applied to characterize the samples. The results showed that substrate, catalyst thickness and type of catalyst are influenced in yield of the growth, structure and quality of MWCNTs. The study has also indicated that MWCNTs grown on Fe-Pd bimetallic catalyst with 25-75 proportion had the highest growth yield. Moreover, decreasing of the growth temperature from 970 to 920 oC produced single-walled carbon nanotubes (SWCNTs) with high quality (IG/ID = 15.8) and low growth yield.... 

    Experimental and Theoretical Study of Methane Adsorption on Multiwall Carbon Nano Tubes

    , M.Sc. Thesis Sharif University of Technology Seddighi, Khosro (Author) ; Taghikhani, Vahid (Supervisor) ; Ghotbi, Siroos (Supervisor)
    Abstract
    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... 

    Electrochemical Determination of Tyrosine and Tryptophan at the Surface of Pyrolytic Graphite Electrode Modified with Multi-Walled Carbon Nanotubes, New Coccine and Nitrazine

    , M.Sc. Thesis Sharif University of Technology Ebrahimi, Shiva (Author) ; Shahrokhian, Saeed (Supervisor)
    Abstract
    At the first part of this thesis, a pyrolitic graphite electrode (PGE) modified with new coccine/multi-walled carbon nanotubes film (NC/MWCNT) was applied as a sensitive electrochemical sensor for determination and study of electrochemical behavior of tyrosine (Tyr) in aqueous solutions. The results showed that NC/MWCNT caused a remarkable increase in the peak current so the NC/MWCNT/PGE electrode surface was far more sensitive to the concentration of Tyr than the PGE surface. The determination of Tyr was investigated by linear sweep voltammetry (LSV). Experimental parameters, such as scan rate, pH and amount of the modifier used on the PGE surface were optimized by monitoring the LSV... 

    Preparation and Application of Carbon Nanotube-polypyrrole Modified Electrode in Electrochemical Determination of Mesalazine

    , M.Sc. Thesis Sharif University of Technology Hosseini Yazdeli, Pouya (Author) ; Shahrokhian, Saeed (Supervisor)
    Abstract
    In this work, the glassy carbon electrode (GCE) was modified with a thin layer of multi-walled carbon nanotubes (MWCNTs) and consequently, electrochemically deposited poly-pyrrole. The electrochemical behavior of mesalazine was studied on the surface of the modified electrode by applying linear sweep voltammetry (LSV). The electro-polymerization process and the electrochemical response toward mesalazine were investigated in the presence of different aromatic anion dopants including, benzenesulfonic acid (BSA), 1,3-benzenedisulfonic acid (1,3-BDSA), 1,5-naphthalenedisulfonic acid (1,5-NDSA) and new coccine (NC). By using 1,5-NDSA as dopant, a significant increase (∼418 times) was observed in... 

    Investigation the Effect of Conductive Scaffolds on Regeneration of the Heart Tissue

    , M.Sc. Thesis Sharif University of Technology Moradpour, Kayvan (Author) ; Vossoughi, Manoochehr (Supervisor) ; Ahmadi Tafti, Hossein (Supervisor)
    Abstract
    Cardiovascular diseases, especially coronary artery disease and coronary heart disease, are the leading cause of death in human communities. After myocardial infarction, known as heart attack, the flow of oxygen to the heart muscle cells is disrupted. It causes the death of cells that leads to structural and functional changes in the heart muscle. Therefore, specialists try to find a way to repair and regenerate the heart muscle after myocardial infarction. Tissue engineering is used to develop substantial alternatives to assist clinical therapies. Recent studies have focused on the construction of scaffolds with various advanced techniques to create guiding channels that mimic the natural... 

    Fabrication and Characterization of Dye-Sensitized Solar Cells based on the hybrids of Multi Wall Carbon Nanotube and Nanostructured TiO2

    , Ph.D. Dissertation Sharif University of Technology Mokarami Ghartavol, Hajar (Author) ; Afshar, Abdollah (Supervisor) ; Mohammadi, Mohammad Reza (Supervisor)
    Abstract
    This study presents a facile sol-gel template-assisted route to prepare CNT-TiO2 hybrid structures (CTH) for dye-sensitized solar cell (DSSC) applications. Non-covalent functionalized multi-walled carbon nanotubes (CNTs) with average diameter of 80 nm are used as the template for TiO2 deposition. The X-ray diffraction reveals that the hybrid structures are composed of primary anatase TiO2 nanoparticles with the average crystallite size of 12 nm, after heat treatment at 450°C in air atmosphere. TEM and FESEM images show that the shell thickness of the coated TiO2 on CNTs’ outmost walls varies between 60 to 120 nm, when the ratio of CNTs:TiO2 is 10wt. %. Photovoltaic measurements demonstrate... 

    EVA /BT/MWCNT Hybrid Composites: Morphology, Electrical and Mechanical Properties

    , M.Sc. Thesis Sharif University of Technology Khodsetan, Haniyeh (Author) ; Frounchi, Masoud (Supervisor)
    Abstract
    In this research, the EVA/BT/MWCNT nanocomposites were prepared via the solution casting method in the various weight fractions of Barium titanate (BT) and multi-walled carbon nanotubes (MWCNT). Barium titanate-based ceramic material has a high dielectric constant, and it is used in the manufacture of sensors, capacitors, and electrical memories. On the other hand, multi-walled carbon nanotubes, due to electric charges on their surface and high electrical conductivity, can affect the dielectric properties combined with barium titanate and the hybrid of these two materials a polymer matrix suitable for special applications. In this study, ethylene-vinyl acetate (EVA) copolymer was used as a...