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    Sol-gel synthesis of thermoluminescent Cd-doped ZnTe nanoparticles

    , Article Indian Journal of Pure and Applied Physics ; Volume 53, Issue 12 , 2015 , Pages 804-807 ; 00195596 (ISSN) Shafiee, S ; Akhavan, O ; Hatami, H ; Hoseinkhani, P ; Sharif University of Technology
    National Institute of Science Communication and Information Resources (NISCAIR)  2015
    Abstract
    The Cd (3 wt%)-doped ZnTe nanoparticles with average size of 5 nm and band gap energy of 3.15 eV were synthesized by sol-gel method. The optical properties (such as band gap energy) and the size distribution of the nanoparticles have been investigated by using UV-Vis spectroscopy and transmission electron microscopy, respectively. Then, thermoluminescence property of the nanoparticles exposed to various doses of gamma radiation of Cs137 has been studied. The thermoluminescence glow peak of the nanoparticles showed a displacement from 290 to 230°C by increasing the dose of gamma radiation from 7.5 to 67.5 mSv. The thermoluminescence intensity of the synthesized Cd-doped ZnTe nanoparticles... 

    Synthesis of TiO2 nano powder by the sol-gel method and its use as a photocatalyst

    , Article Journal of the Iranian Chemical Society ; Volume 7, Issue SUPPL. 1 , 2010 , Pages S154-S160 ; 1735207X (ISSN) Karami, A ; Sharif University of Technology
    2010
    Abstract
    In this work the titanium dioxide powder was prepared by the optimized and simple Sol-Gel method and then characterized. The gelling pH was set to values of 3 (TiO2-A), 7 (TiO2-N) and 9 (TiO2-B) to observe the effect on the properties of the material. In these three cases nanoparticulated materials were obtained with particle sizes between 10nm and 20nm. The larger surface areas were obtained at pH 3, which is several times larger than the others. Furthermore, with the gelling condition pH 3, it was possible to synthesize pure anatase phase titania. Some preliminary results on the test of the photocatalytic activity of the synthesized materials in the reduction of nitric oxide are presented.... 

    Optimization of synthetic conditions CMC-g-poly (acrylic acid)/celite composite superabsorbent by taguchi method and determination of its absorbency under load

    , Article Express Polymer Letters ; Volume 1, Issue 8 , 2007 , Pages 488-494 ; 1788618X (ISSN) Pourjavadi, A ; Amini Fazl, M. S ; Ayyari, M ; Sharif University of Technology
    2007
    Abstract
    A novel biopolymer-based composite hydrogel was synthesized through chemical crosslinking by graft copolymerization of partially neutralized acrylic acid onto the carboxymethyl cellulose (CMC). The Taguchi method, a robust experimental design, was employed for the optimization of the synthesis based on the swelling capacity of the hydrogels. This method was applied for the experiments and standard L16 orthogonal array with five factors and four levels. In the synthesis of the composite superabsorbent, N,N'-methylene bisacrylamide (MBA) as crosslinker, ammonium persulfate (APS) as initiator, acrylic acid (AA) as monomer, CMC/Celite weight ratio and neutralization percent (NU) were used as... 

    Oxidation of alcohols with 4-aminopyridinium chlorochromate supported on silica gel

    , Article Monatshefte fur Chemie ; Volume 135, Issue 7 , 2004 , Pages 793-797 ; 00269247 (ISSN) Hashemi, M. M ; Ghazanfari, D ; Akhbari, M ; Sharif University of Technology
    Springer Wien  2004
    Abstract
    4-Aminopyridinium chlorochromate supported on silica gel was found to be an efficient reagent for the oxidation of primary and secondary alcohols to the corresponding carbonyl compounds. © Springer-Verlag 2004  

    Oxidation of thiols to bisulfides by oxygen in presence of cobalt(ii) and manganese(ii) salts of 4-aminobenzoic acid supported on silica gel

    , Article Monatshefte fur Chemie ; Volume 135, Issue 1 , 2004 , Pages 41-43 ; 00269247 (ISSN) Hashemi, M. M ; Karimi Jaberi, Z ; Sharif University of Technology
    2004
    Abstract
    A mixture of cobalt(II) and manganese(II) salts of 4-aminobenzoic acid supported on silica gel catalyses the oxidation of thiols to disulfides in the presence of oxygen or air  

    Cobalt and Manganese Salts of p-Aminobenzoic Acid Supported on Silica Gel: A Versatile Catalyst for Oxidation by Molecular Oxygen

    , Article Monatshefte fur Chemie ; Volume 134, Issue 3 , 2003 , Pages 411-418 ; 00269247 (ISSN) Hashemi, M. M ; Ahmadibeni, Y ; Sharif University of Technology
    2003
    Abstract
    A 1:1 molar ratio of the cobalt and manganese salts of p-amino benzoic acid supported on silica gel is an effective catalyst for the oxidation of various organic compounds in reasonable yields using molecular oxygen. The catalyst can be reused several times  

    Simultaneous preconcentration and speciation of iron(II) and iron(III) in water samples by 2-mercaptobenzimidazole-silica gel sorbent and flow injection analysis system

    , Article Analytica Chimica Acta ; Volume 424, Issue 2 , 2000 , Pages 233-242 ; 00032670 (ISSN) Bagheri, H ; Gholami, A ; Najafi, A ; Sharif University of Technology
    2000
    Abstract
    2-Mercaptobenzimidazole, loaded on silica gel (MBI-SG) was used for preconcentration and speciation of iron(II) and iron(III) in water samples. The speciation is based upon selective retention of iron(III) on MBI-SG sorbent and quantitatively passing iron(II) ions. This type of sorbent was not only capable of separating theses two ions but also could concentrate them. The adsorbed iron(III) on MBI-SG was desorbed from the column by an SCN- solution and transferred to the detection device. The effluent, then, was treated with hydrogen peroxide to oxidize iron(II) into iron(III) and subsequently was pumped through the MBI-SG column. A home-made flow injection system was coupled with a UV-VIS... 

    A mild and efficient oxidation of benzylic alcohols without solvent using iodic acid supported on wet montmorillonite K10 or silica gel under microwave irradiation

    , Article Acta Chimica Slovenica ; Volume 52, Issue 1 , 2005 , Pages 86-87 ; 13180207 (ISSN) Hashemi, M. M ; Rahimi, A ; Karimi Jaberi, Z ; Ahmadibeni, Y ; Sharif University of Technology
    2005
    Abstract
    Iodic acid supported on wet silica gel and K10 clay are used for the efficient oxidation of benzylic alcohols under microwave irradiation and solvent free condition  

    An enhancement in the photocatalytic activity of TiO 2 by the use of Pd: The question of layer sequence in the resulting hierarchical structure

    , Article Journal of Coatings Technology Research ; Volume 8, Issue 1 , January , 2011 , Pages 75-81 ; 15470091 (ISSN) Rezaeian Delouei, M ; Ghorbani, M ; Mohsenzadeh, M ; Sharif University of Technology
    2011
    Abstract
    TiO 2 and Pd-modified TiO 2 photocatalysts were prepared by sol-gel method. X-ray diffraction (XRD) data showed that the presence of Pd in TiO 2 catalyst decreases the crystalline size of TiO 2 and stabilizes anatase phase. The study of the photocatalytic activity of the films via Linear Sweep Voltametry (LSV) plots and antibacterial test against Escherichia coli ATCC 25922-a gram negative bacterium-showed that Pd increases the photocatalytic activity of the coatings. Besides, the sequence of layer deposition (TiO 2 and Pd-modified TiO 2) influences the photocatalytic properties. In other words, more photocatalytic activity is obtained when Pd-modified layer is deposited first  

    Investigation into some parameters affecting pectin gel quality

    , Article Scientia Iranica ; Volume 14, Issue 2 , 2007 , Pages 174-179 ; 10263098 (ISSN) Ebrahimi, B ; Alemzadeh, I ; Seifkordi, S. K ; Sharif University of Technology
    Sharif University of Technology  2007
    Abstract
    In this research, gel production from the extracted pectin gel of shahroud sugar beet pulp has been investigated. The pectin extractions were performed in a cold alkaline solution and a hot acid solution, respectively. The effects of different parameters, such as percent of sugar, pectin concentration, calcium content and quantity of peroxidase enzyme, hardness and content of water absorbed by the gel, were studied. Optimum conditions for production of favorable gel, from extracted pectin in this research are, as follows: Percent of sugar (glucose): 15%, peroxidase enzyme content: (pectin unit) 170 pu/g of pectin, pectin concentration (if only gel water uptake is important): 10%, pectin... 

    Effective photocatalytic degradation of an azo dye over nanosized Ag/AgBr-modified TiO2 loaded on zeolite

    , Article Journal Chemical Papers ; Volume 65, Issue 3 , June , 2011 , pp 280-288 ; 1336-9075 Padervand, M. (Mohsen) ; Tasviri, M. (Mahboubeh) ; Gholami, M. R. (Mohammad Reza) ; Sharif University Of Technology
    Abstract
    Zeolite-based photocatalysts were prepared by the sol-gel and deposition methods. The photocatalysts were characterised by X-ray diffraction, nitrogen adsorption-desorption isotherms, FTIR spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectrometry. The activity of the prepared photocatalysts was evaluated by the UV-induced degradation of acid blue 92, a textile dye in common use. The effect of various parameters, such as catalyst concentration, initial dye concentration, thiosulphate concentration and pH, on the rate and efficiency of the photocatalytic degradation of acid blue 92 was investigated. The results showed that each parameter influenced the degradation... 

    Investigation of the antibacterial and photocatalytic properties of the zeolitic nanosized AgBr/Tio2 composites

    , Article Materials Science in Semiconductor Processing ; Volume 15, Issue 1 , February , 2012 , Pages 73–79 Padervanda, M. (Mohsen) ; Elahifard, M. R. (Mohammad Reza) ; Vatan Meidanshahi, R. (Reza) ; Ghasemi, S. (Shahnaz) ; Haghighi, S. (Saeed) ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
    Abstract
    Zeolite-based Ag/AgBr and Ag/AgBr/TiO2 photocatalysts were prepared by sol–gel and deposition methods and were characterized. Their photocatalytic activities were evaluated by inactivation of Escherichia (E.) coli and the photodegradation of Acid Blue 92 and potassium permanganate. The composites containing Ag/AgBr showed the antibacterial activity in the dark by releasing Ag+ ions into the medium. The results for inactivation of E. coli indicated that Ag/AgBr/TiO2 modified photocatalyst had better antibacterial activity than Ag/AgBr/zeolite, while zeolite and TiO2/zeolite did not show any antibacterial activity under visible light and dark conditions. Photodecolarization rate was affected... 

    Double layer bioglass-silica coatings on 316L stainless steel by sol-gel method

    , Article Ceramics International ; Volume 40, Issue 1, Part A , January 2014 , Pages 993–1000 Pourhashem, S ; Afshar, A ; Sharif University of Technology
    Abstract
    The application of bioglass coatings on metallic implants provides link between bone and materials and prevents corrosion of metallic implants in body fluid. Therefore, in this research, 45S5 bioglass-silica coatings on 316L stainless steel were prepared by the sol-gel method and were characterized by different techniques. According to X-ray diffraction (XRD) results, by sintering 45S5 bioglass at 600 C for 5 h, coatings containing both amorphous phase and Na2Ca2Si3O9 crystalline phase were obtained. Scanning electron microscopy (SEM) results showed that coatings prepared via appropriate sol aging and substrate preparations are crack-free. Potentiodynamic polarization tests in simulated body... 

    Synthesis and properties of MWCNT-HAP composites via sol-gel technique

    , Article Iranian Journal of Materials Science and Engineering ; Volume 10, Issue 2 , 2013 , Pages 57-63 ; 17350808 (ISSN) Jafaripour Maybody, J ; Nemati, A ; Salahi, E ; Sharif University of Technology
    2013
    Abstract
    In the present study, bioceramic composites based hydroxyapatite (HAp) reinforced with carbon nanotubes (CNTs) was synthesized via sol-gel technique. The dried gels were individually heated at a rate of 5°C/min up to 600°C for 2 h in a muffle furnace in order to obtain HAp-MWCNTs mixed powder. Composites were characterized by XRD, FT-IR, SEM, TEM/SAED/EDX and Raman spectroscopy techniques. Results showed the synthesis of HAp particles in the MWCNTs sol which was prepared in advance, leads to an excellent dispersion of MWCNTs in HAp matrix. Apparent average size of crystallites increased by increasing the percentage of MWCNTs. The average crystallite size of samples (at 600°C), estimated by... 

    Discrimination of Sol and Gel states in an aging clay suspension

    , Article Chemical Physics ; Volume 423 , September , 2013 , Pages 167-172 ; 03010104 (ISSN) Shayeganfar, F ; Movahed, M. S ; Jafari, G. R ; Sharif University of Technology
    2013
    Abstract
    The dynamical scattered light intensity and multiplicative cascade model was employed to characterize the anisotropic charged colloidal particles suspension during the so-called Sol-Gel transition. Generally we looked for finding a criterion to distinguish the properties of Sol and Gel states systematically. The probability density function (PDF) of the light scattering intensity shows an obvious change with proceeding of the sample aging process (during of gelation state). Our results confirmed that in the so-called Sol state, the value of non-Gaussian parameter, kW, as a function of time is larger than that of for weak-Gel or in coexistence Sol-Gel state. The number of cascades in the... 

    A modified method for barium titanate nanoparticles synthesis

    , Article Materials Research Bulletin ; Volume 46, Issue 12 , 2011 , Pages 2291-2295 ; 00255408 (ISSN) Ashiri, R ; Nemati, A ; Sasani Ghamsari, M ; Sanjabi, S ; Aalipour, M ; Sharif University of Technology
    2011
    Abstract
    In this research, a modified, cost effective sol-gel procedure applied to synthesize BaTiO3 nanoparticles. XRD and electron microscopy (SEM and TEM) applied for microstructural characterization of powders. The obtained results showed that the type of precursors, their ratio and the hydrolysis conditions had a great effect on time, temperature and therefore the costs of the synthesis process. By selection, utilization of optimized precursor's type, hydrolysis conditions, fine cubic BaTiO3 nanoparticles were synthesized at low temperature and in short time span (1 h calcination at 800 °C). The proposed procedure seems to be more preferable for mass production. The result indicated that the... 

    Synthesis of C-N-Y tri-doped TiO2 photo-catalyst for MO degradation and characterization

    , Article Materials Research Express ; Volume 2, Issue 10 , October , 2015 ; 20531591 (ISSN) Hoseinian Maleki, F ; Nemati, A ; Joya, Y. F ; Sharif University of Technology
    Institute of Physics Publishing  2015
    Abstract
    In this researchC-N-Y tri-doped TiO2 nanopowders were synthesized by the sol-gel method. TheC- N-Y Ti O2 photo-catalyst was prepared using hexamine and yttrium nitrate Hexahydrate as the dopant precursors. Methyl-orange (MO) was used to study the photocatalytic performance of the doped Ti O2 underUVirradiation. The synthesized samples were characterized by x-ray diffraction, x-ray photoelectron spectroscopy,UV-vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, Transmission electron microscopy, Photoluminescence and Field emission scanning electron microscopy. The tri-doped sample with8%N, 0.4% Y and 1.5%Cexhibited enhanced photocatalytic efficiencies. After 100... 

    Performance of polyacrylamide/Cr(III) gel polymer in oil recovery from heterogeneous porous media: An experimental study

    , Article Korean Journal of Chemical Engineering ; Volume 33, Issue 12 , 2016 , Pages 3350-3358 ; 02561115 (ISSN) Kargozarfard, Z ; Riazi, M ; Ayatollahi, S ; Shahnazar, S ; Sharif University of Technology
    Springer New York LLC 
    Abstract
    Water channeling due to reservoir heterogeneity is an important factor that could decrease the displacement efficiency of a water flooding process. In this study, the ability of polyacrylamide/ chromium acetate system on altering water path in heterogeneous layered media was investigated using glass bead micromodels. After the relevant parameters were optimized, a series of water and gel injection experiments were conducted in glass bead micromodel. The experimental results show that sweep efficiency is basically controlled by gel strength. The gel strength has a minor impact on the oil recovery from the higher permeable zone, whereas the oil recovery from the lower permeable zone is a... 

    Lithium iron silicate sol–gel synthesis and electrochemical investigation

    , Article Journal of Alloys and Compounds ; Volume 672 , 2016 , Pages 93-97 ; 09258388 (ISSN) Oghbaei, M ; Baniasadi, F ; Asgari, S ; Sharif University of Technology
    Elsevier Ltd 
    Abstract
    Li2FeSiO4 was synthesized through Sol–Gel method and the effect of calcination temperature, time and chelating agent concentration were investigated. Appropriate calcination temperature above 550 °C was determined by TG/DTA analysis. Afterward, the dried gel powder was calcined at each temperature of 650 °C, 700 °C and 750 °C for 1, 2 and 3 h. XRD studies illustrated the most appropriate calcination temperature of 700 °C for 1 h. To compare the effect of chelating agent concentration, citric acid with molar ratio of 1/3, 2/3 and 1 were used which 1/3 was determined as the best concentration. FE-SEM observation showed that mean grain is size lower than 100 nm. By using this material, a three... 

    Are aluminium titanate-based nanostructures new photocatalytic materials? Possibilities and perspectives

    , Article Journal of Photochemistry and Photobiology A: Chemistry ; Volume 353 , 2018 , Pages 316-324 ; 10106030 (ISSN) Bakhshandeh, F ; Azarniya, A ; Madaah Hosseini, H. R ; Jafari, S ; Sharif University of Technology
    Elsevier B.V  2018
    Abstract
    Nanostructured aluminum titanate (AT) was synthesized by the sol-gel method. The calcination temperature was selected as a processing variable to obtain different phase ratios of AT and its parent phases i.e. TiO2 and Al2O3. The main aim behind the present work was to cast light on the photocatalytic performance of AT-based nanocomposites and evaluate their capability to serve as a novel photocatalyst. X-ray diffraction (XRD) analysis and field-emission scanning electron microscopy (FE-SEM) studies were conducted to evaluate the microstructure-sensitive properties of the synthesized powders. Diffuse reflectance spectroscopy (DRS) and the methylene blue degradation test were carried out to...