Search for: fourier-transform-infrared-spectroscopy
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    Generic extraction medium: From highly polar to non-polar simultaneous determination

    , Article Analytica Chimica Acta ; Volume 1066 , 2019 , Pages 1-12 ; 00032670 (ISSN) Zeinali, S ; Khalilzadeh, M ; Bagheri, H ; Sharif University of Technology
    Elsevier B.V  2019
    Sample preparation for non-target analysis is challenging due to the difficulty in the extraction of polar and non-polar analytes simultaneously. Most commercial solid sorbents lack the proper comprehensiveness for extraction of analytes with different physiochemical properties. A possible key is the combination of hydrophobic polymer and hydrophilic surface functional groups in solid based extraction methods in order to generate the susceptibility for retaining both polar and non-polar analytes. To pursue this goal, in this study, four polar groups including [sbnd]NH 2 , [sbnd]NO 2 , [sbnd]COOH, and [sbnd]COCH 3 were chemically bound to Amberlite XAD-4 substrate in order to prepare a... 

    In vitro bactericidal and drug release properties of vancomycin-amino surface functionalized bioactive glass nanoparticles

    , Article Materials Chemistry and Physics ; Volume 241 , 2020 Zarghami, V ; Ghorbani, M ; Bagheri, K.P ; Shokrgozar, M. A ; Sharif University of Technology
    Elsevier Ltd  2020
    Bioactive glass has been used clinically in bone repair applications for bone grafting because of its prominent physiochemical and osteogenic properties. Various attempts have been made to enhance bioactive glass efficiency in combination with other biomaterials such as antibiotics and growth factors. In present study, we developed a modification of bioactive glass nanoparticles that insured long term antibacterial effect. Bioactive glass nanoparticles (BGNs) were functionalized with (3-Aminopropyl) triethoxysilane (APTS), then vancomycin (VAN) was immobilized onto BGNs-APTS via EDC/NHS cross-linking process. Another study group namely BGNs-VAN was synthesized as a control group without any... 

    Biomimetic proteoglycan nanoparticles for growth factor immobilization and delivery

    , Article Biomaterials Science ; Volume 8, Issue 4 , 2020 , Pages 1127-1136 Zandi, N ; Mostafavi, E ; Shokrgozar, M. A ; Tamjid, E ; Webster, T. J ; Annabi, N ; Simchi, A ; Sharif University of Technology
    Royal Society of Chemistry  2020
    The delivery of growth factors is often challenging due to their short half-life, low stability, and rapid deactivation. In native tissues, the sulfated residual of glycosaminoglycan (GAG) polymer chains of proteoglycans immobilizes growth factors through the proteoglycans'/proteins' complexation with nanoscale organization. These biological assemblies can influence growth factor-cell surface receptor interactions, cell differentiation, cell-cell signaling, and mechanical properties of the tissues. Here, we introduce a facile procedure to prepare novel biomimetic proteoglycan nanocarriers, based on naturally derived polymers, for the immobilization and controlled release of growth factors.... 

    Thermally oxidized Nanodiamond: an effective sorbent for separation of methotrexate from aqueous media: synthesis, characterization, in vivo and in vitro biocompatibility study

    , Article Journal of Inorganic and Organometallic Polymers and Materials ; Volume 29, Issue 3 , 2019 , Pages 701-709 ; 15741443 (ISSN) Zamani, M ; Aghajanzadeh, M ; Molavi, H ; Danafar, H ; Shojaei, A ; Sharif University of Technology
    Springer New York LLC  2019
    In the present study the effect of nanodiamond (ND) on the adsorption capacity of Drug has been investigated. Thermal oxidation nanodiamond (OND) was used as adsorbents for Methotrexate adsorption. The surface properties of NDs were studied by Fourier transform infrared spectroscopy and zeta potential. It was determined that thermal oxidation changed the surface properties of ND, including increase the amount of carboxylic acid groups and decreasing the zeta potential of ND by increasing the thermal oxidation time. The adsorption experiments showed that untreated ND (UND) has large adsorption capacity and fast adsorption kinetic for methotrexate (MTX). These results suggest that the... 

    Synthesis of cellulose acetate/chitosan/SWCNT/Fe3O4/TiO2 composite nanofibers for the removal of Cr(VI), As(V), Methylene blue and Congo red from aqueous solutions

    , Article International Journal of Biological Macromolecules ; Volume 140 , 2019 , Pages 1296-1304 ; 01418130 (ISSN) ZabihiSahebi, A ; Koushkbaghi, S ; Pishnamazi, M ; Askari, A ; Khosravi, R ; Irani, M ; Sharif University of Technology
    Elsevier B.V  2019
    The potential of electrospun cellulose acetate/chitosan/single walled carbon nanotubes/ferrite/titanium dioxide (CA/chitosan/SWCNT/Fe3O4/TiO2) nanofibers was investigated for the removal of Cr(VI), As(V), Methylene blue and Congo red from aqueous solutions via the adsorption and photocatalytic reduction processes. The properties of synthesized SWCNT/Fe3O4/TiO2 and fibers were characterized using TEM, SEM, FTIR, XRD, TGA and BET analysis. In adsorption process, the influence of adsorbent type including SWCNT to Fe3O4 ratio, TiO2 to SWCNT/Fe3O4 ratio and SWCNT/Fe3O4/TiO2 concentration as well as the adsorption parameters including pH, contact time, and initial concentration of adsorbates on... 

    Preparation of new titanium nitride-carbon nanocomposites in supercritical benzene and their oxygen reduction activity in alkaline medium

    , Article Electrochimica Acta ; Volume 164 , May , 2015 , Pages 114-124 ; 00134686 (ISSN) Yousefi, E ; Ghorbani, M ; Dolati, A ; Yashiro, H ; Outokesh, M ; Sharif University of Technology
    Elsevier Ltd  2015
    Titanium nitride-carbon nanocomposites are synthesized by the reaction of TiCl4 and NaN3 in supercritical benzene medium that also serves as a carbon source. The as-prepared precursors (SI, SII) are subjected to several heat treatments (SIII-SV). The synthesized nanoparticles are characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The samples are tested as electrocatalyst for oxygen reduction reaction in an alkaline electrolyte. It is shown that the electrocatalytic properties of the synthesized nanoparticles are... 

    Two new swinging interferometers

    , Article Journal of Optics A: Pure and Applied Optics ; Volume 9, Issue 7 , 2007 , Pages 560-564 ; 14644258 (ISSN) Yazdi, S ; Rashidian, B ; Sharif University of Technology
    The most important disadvantage of swinging interferometers is that the optical path difference created in them is a nonlinear function of the rotation angle. In this paper, two new swinging interferometers are presented which have good linearity and provide a larger path difference in response to the rotation angle compared to other interferometers. This makes them suitable for applications such as high-resolution spectroscopy, and precision micro and nanopositioning. In one of these two interferometers, the optical path difference is created by rotation of a system composed of four mirrors, and in the other one it is created by rotation of a system consisting of two mirrors. They are not... 

    Bottom-up synthesis of nitrogen and oxygen co-decorated carbon quantum dots with enhanced DNA plasmid expression

    , Article Colloids and Surfaces B: Biointerfaces ; Volume 184 , 2019 ; 09277765 (ISSN) Yadegari, A ; Khezri, J ; Esfandiari, S ; Mahdavi, H ; Karkhane, A. A ; Rahighi, R ; Heidarimoghadam, R ; Tayebi, L ; Hashemi, E ; Farmany, A ; Sharif University of Technology
    Elsevier B.V  2019
    In this paper, a bottom-up hydrothermal route is reported for the synthesis of oxygen and nitrogen co-decorated carbon quantum dots (CQDs) using ammonium hydrogen citrate (AHC) as a single precursor. DLS data approved the formation of 4.0 nm (average size) CQDs. XRD pattern shows the interlayer spacing (002) of 3.5 Å for CQDs, which is exactly the same as that of crystalline graphite. XPS and FTIR spectra verified the formation of oxygen and nitrogen functional groups on the CQDs surface. Co-decorated carboxyl, hydroxyl and amine groups on the CQDs surfaces make them as promising polyelectrolyte for gene delivery. Toxicity assay showed a survival rate of 70% under different incubation times... 

    Co-microencapsulation of lactobacillus plantarum and DHA fatty acid in alginate-pectin-gelatin biocomposites

    , Article Carbohydrate Polymers ; Volume 199 , 2018 , Pages 266-275 ; 01448617 (ISSN) Vaziri, A. S ; Alemzadeh, I ; Vossoughi, M ; Chackoshian Khorasani, A ; Sharif University of Technology
    The aim of this study was to investigate the co-microencapsulation of Lactobacillus plantarum and DHA-rich oil in a novel gastrointestinal-resistant biocomposite composed of alginate, pectin and gelatin. The optimal biocomposite consisted of 1.06% alginate, 0.55% pectin and 0.39% gelatin showed 88.66% survivability of the microencapsulated cells compared to the free cells (50.36%). In addition, co-microencapsule containing probiotic and DHA fatty acid was synthesized and physicochemically analyzed using SEM, FTIR, TGA, XRD. The results from SEM clearly confirmed that cells were completely entrapped in the matrix and DHA increased smoothness and compactness of the surface of the particles.... 

    Degradation of azo dye methyl red by saccharomyces cerevisiae ATCC 9763

    , Article International Biodeterioration and Biodegradation ; Volume 125 , 2017 , Pages 62-72 ; 09648305 (ISSN) Vatandoostarani, S ; Bagheri Lotfabad, T ; Heidarinasab, A ; Yaghmaei, S
    Azo dyes are common dye groups widely used in different industries. Industrial effluents which contain these dyes pervade water resources and have various known and unknown physiological effects on living organisms. In this study, methyl red (MR) was proposed as a model azo dye to examine the capability of Saccharomyces cerevisiae ATCC 9763 for cleavage of the azo bond leading to decolourization. The spectrophotometry method showed that complete decolourization occurred statically during ≃12 h and this time reduced to several minutes less than 10 min where cell mass increased. Thin layer chromatography (TLC), mass spectroscopy and Fourier transform infrared (FTIR) confirmed degradation of... 

    Structural and optical properties of Fe and Zn substituted CuInS2 nanoparticles synthesized by a one-pot facile method

    , Article Journal of Materials Chemistry C ; Volume 3, Issue 4 , Nov , 2015 , Pages 889-898 ; 20507534 (ISSN) Vahidshad, Y ; Tahir, M. N ; Zad, A. I ; Mirkazemi, S. M ; Ghazemzadeh, R ; Tremel, W ; Sharif University of Technology
    Royal Society of Chemistry  2015
    We substitute indium present in the CuInS2 ternary compound by iron and zinc using a facile one-pot synthesis method. The quaternary compound of CuIn1-xMxS2 (M = Fe and Zn) was synthesized by dissolving CuCl, InCl3, FeCl3, Zn(ac)2 and SC(NH2)2 as precursors in 1-octadecene, oleylamine and oleic acid as non-coordinating, coordinating and capping agent solvents, respectively. Oleic acid, oleylamine and thiourea were used respectively as a hard Lewis base, borderline Lewis base (in comparison with oleic acid) and soft Lewis base to form appropriate complexes. The complex formation, structure, and... 

    A study of structural, magnetic and various dielectric parameters of Ca-Substituted W-Type hexaferrites for applications at 1–6 GHz frequencies

    , Article Journal of Electronic Materials ; Volume 48, Issue 11 , 2019 , Pages 7149-7161 ; 03615235 (ISSN) ur Rehman, A ; Shaukat, S. F ; Akhtar, M. N ; Ahmad, M ; Sharif University of Technology
    Springer New York LLC  2019
    Single phase Ca-substituted W-type hexaferrites Sr1-xCaxZn2Fe16O27(x = 0.00(0.25)1.00) have successfully been synthesized by using sol–gel self-combustion at 1300°C. These hexaferrites are investigated by x-ray difrractometry (XRD), scanning electron microscopy, energy dispersive x-ray spectroscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometry, and vector network analysis. XRD analysis confirms the formation of a single W-type hexaferrites phase. The DC electrical resistivity increases with incrementing Ca contents. The morphology of all the hexaferrites shows hexagonal platelet-like structure. The prepared ferrites depict soft magnetic nature with high saturation... 

    Synthesis of Reduced Graphene Oxide-Carbon Nanotubes (rGO-CNT) Composite and Its Use As a Novel Catalyst Support for Hydro-Purification of Crude Terephthalic Acid

    , Article Industrial and Engineering Chemistry Research ; Volume 54, Issue 31 , 2015 , Pages 7591-7603 ; 08885885 (ISSN) Tourani, S ; Rashidi, A. M ; Safekordi, A. A ; Aghabozorg, H. R ; Khorasheh, F ; Sharif University of Technology
    American Chemical Society  2015
    Palladium nanocatalysts supported on reduced graphene oxide (rGO), multi walled carbon nanotubes (MWCNT), and rGO/CNT composite were synthesized by a wet impregnation method using PdCl2 as a precursor. Palladium loading was 0.3 wt %, and the catalysts were reduced at 300°C. The catalysts were characterized by inductively coupled plasma, Brunauer-Emmett-Teller (BET) analysis, Fourier transform infrared spectroscopy, X-ray powder diffraction, transmission electron microscopy, temperatue-programmed reduction, temperatue-programmed desorption, and Raman spectroscopy. The performance of the catalysts was investigated for hydro-purification of crude terephthalic acid (CTA) containing... 

    Investigation of Tabas anthracite coal devolatilization: Kinetics, char structure and major evolved species

    , Article Thermochimica Acta ; Volume 654 , 2017 , Pages 74-80 ; 00406031 (ISSN) Toloue Farrokh, N ; Askari, M ; Fabritius, T ; Sharif University of Technology
    Elsevier B.V  2017
    The pyrolysis of low-volatile Tabas anthracite coal was investigated by thermogravimetric technique (TGA) in the temperature range from ambient to 1100 °C under non-isothermal heating conditions (1.5, 3, and 7 °C/min heating rates). Higher heating rates showed a small retarding effect on devolatilization toward higher temperatures. Iso-conversional method was used for the kinetic study of non-isothermal Thermogravimetric data. Activation energy calculated for coal conversion of 20–80% was about 319 kJ/mol which may be a result of stable ordered structure of this type of coal. Analysis of evolved gases by Fourier transform infrared spectrometry (FTIR) in 7 °C/min heating rate was conducted... 

    Polyelectrolyte nanocomposite membranes using imidazole-functionalized nanosilica for fuel cell applications

    , Article Journal of Macromolecular Science, Part B: Physics ; Volume 54, Issue 1 , Nov , 2015 , Pages 17-31 ; 00222348 (ISSN) Tohidian, M ; Ghaffarian, S. R ; Nouri, M ; Jaafarnia, E ; Haghighi, A. H ; Sharif University of Technology
    Taylor and Francis Inc  2015
    The preparation and characterization of a new type of nanocomposite polyelectrolyte membrane, based on DuPont Nafion/imidazole-modified nanosilica (Im-Si), for direct methanol fuel cell applications is described. Related to the interactions between the protonated imidazole groups, grafted on the surface of nanosilica, and negatively charged sulfonic acid groups of Nafion, new electrostatic interactions can be formed in the interface of Nafion and Im-Si which result in both lower methanol permeability and also higher proton conductivity. Physical characteristics of these manufactured nanocomposite membranes were investigated by scanning electron microscopy, thermogravimetry analysis,... 

    XPS study of size effects of Fe3O4 nanoparticles on crosslinking degree of magnetic TFN membrane

    , Article Polymer Testing ; Volume 73 , 2019 , Pages 232-241 ; 01429418 (ISSN) Tayefeh, A ; Poursalehi, R ; Wiesner, M ; Mousavi, S. A ; Sharif University of Technology
    Elsevier Ltd  2019
    The control of thin film nanocomposite (TFN) membranes cross-linking degree is an important factor to design new membranes and optimizing permeation characteristics. The Fe3O4 nanoparticle's based TFN membranes due to potentially added magnetic responsive properties to the membrane has a great importance in developing membrane architectures. Fe3O4/polyamide (PA) TFN membranes filled with nanoparticles in different sizes and concentrations have been synthesized. Cross-linking degree of PA layer characterized with Fourier transform spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS) methods to evaluate size dependency of the cross-linking degree of PA layer network. Obvious... 

    Supercritical synthesis and in situ deposition of PbS nanocrystals with oleic acid passivation for quantum dot solar cells

    , Article Materials Chemistry and Physics ; Volume 156 , 2015 , Pages 163-169 ; 02540584 (ISSN) Tavakoli, M. M ; Simchi, A ; Aashuri, H ; Sharif University of Technology
    Elsevier Ltd  2015
    Colloidal quantum dot solar cells have recently attracted significant attention due to their low-processing cost and surging photovoltaic performance. In this paper, a novel, reproducible, and simple solution-based process based on supercritical fluid toluene is presented for in situ growth and deposition PbS nanocrystals with oleic-acid passivation. A lead precursor containing sulfur was mixed with oleic acid in toluene and processed in a supercritical fluid condition at different temperatures of 140, 270 and 330 °C for 20 min. The quantum dots were deposited on a fluorine-doped tin oxide glass substrate inside the supercritical reactor. Transmission electron microscopy, X-ray diffraction,... 

    Enhancing the photocatalytic performance of Ag3PO4 by incorporating g-C3N4 and MWCNTs: Optimisation of removal of Acid Blue 92

    , Article Progress in Reaction Kinetics and Mechanism ; Volume 41, Issue 3 , 2016 , Pages 277-288 ; 14686783 (ISSN) Tasviri, M ; Armandsefat, F ; Mohaghegh, N ; Ahmadinasab, N ; Sharif University of Technology
    Science Reviews 2000 Ltd  2016
    The main aim of the present study was to enhance the degradation capacity of Acid Blue 92 (AB92) by visible-light-active Ag3PO4 nanocomposites based on g-C3N4 and Multiwalled Carbon Nanotubes (MWCNTs). The nanocomposites were fabricated through a tunable in situ deposition method. The properties of the resulting samples were investigated by X-ray diffraction, scanning electron microscopy and Fourier transform infrared (FTIR) spectroscopy. The photocatalytic activity results revealed that the Ag3PO4/g-C3N4 heterojunction inorganic/organic composite exhibited an improvement in both efficiency and the rate of AB92 photodegradation in comparison with the others. The enhanced photocatalytic... 

    Polyphosphate-reduced graphene oxide on Ni foam as a binder free electrode for fabrication of high performance supercapacitor

    , Article Electrochimica Acta ; Volume 296 , 2019 , Pages 130-141 ; 00134686 (ISSN) Talebi, M ; Asen, P ; Shahrokhian, S ; Ahadian, M. M ; Sharif University of Technology
    Elsevier Ltd  2019
    Polyphosphate reduced graphene oxide on Ni foam (PPO-RGO/NF) is synthesized by varying weight ratios of Na5P3O10 (PO): graphene oxide (GO) with a simple, scalable and low cost method through freeze-drying of the PO-GO/NF followed by thermal treatment of the prepared electrodes. The resulting samples are characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), Brunauer-Emmett-Teller (BET), and raman spectroscopy methods. The results show that the weight ratio of PO:GO, considerably affect the... 

    High-performance carboxylate superplasticizers for concretes: Interplay between the polymerization temperature and properties

    , Article Journal of Applied Polymer Science ; Volume 134, Issue 23 , 2017 ; 00218995 (ISSN) Tajbakhshian, A ; Saeb, M. R ; Jafari, S. H ; Najafi, F ; Khonakdar, H. A ; Ayoubi, M ; Hassanpour Asl, F ; Sharif University of Technology
    Polycarboxylate superplasticizers based on acrylic acid (AA) and maleic anhydride (MAn) were synthesized via free-radical copolymerization with an ethylene glycol monomer and characterized. The copolymerization temperature (ranging from 50 to 90 °C) appeared to be the key operating factor governing the chemical structure of the superplasticizers. The chemical structures of the products were analyzed by gel permeation chromatography, whereas an optimized sample was further analyzed by Fourier transform infrared spectroscopy and 1H-NMR. Superplasticizers of the AA and MAn classes were then incorporated into concrete, and their performances were measured by slump and slump loss tests, where a...