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    Preconcentration and determination of carbaryl and carbofuran in water samples using ionic liquids and in situ solvent formation microextraction

    , Article Analytical Methods ; Volume 5, Issue 9 , 2013 , Pages 2406-2412 ; 17599660 (ISSN) Tehrani, M. S ; Givianrad, M. H ; Akhoundi, L ; Akhoundi, M ; Sharif University of Technology
    In the present work, a novel microextraction method named in situ solvent formation microextraction (ISFME) using ionic liquids (ILs) for preconcentration of carbaryl and carbofuran in water samples is introduced. In this method, a small amount of sodium hexafluorophosphate (NaPF6), as an ion pairing agent, was added to a sample solution containing a small quantity of 1-hexyl-3-methylimidazolium tetrafluoroborate [Hmim][BF4] as a hydrophobic ionic liquid. A cloudy solution formed as a result of formation of fine droplets of 1-hexyl-3-methylimidazolium hexafluorophosphate [Hmim][PF 6]. After centrifugation, the fine droplets of the extractant phase settled to the bottom of the conical-bottom... 

    Applying a robust solution based on expert systems and GA evolutionary algorithm for prognosticating residual gas saturation in water drive gas reservoirs

    , Article Journal of Natural Gas Science and Engineering ; Vol. 21, issue , November , 2014 , p. 79-94 Tatar, A ; Yassin, M. R ; Rezaee, M ; Aghajafari, A. H ; Shokrollahi, A ; Sharif University of Technology
    In strong water drive gas reservoirs (WDGRs), the water encroachment in the gas zone has adverse effects on the gas mobility and causes considerable volume of gas to be trapped behind water front; therefore estimation of residual gas saturation after water influx is an important parameter in estimation of gas reservoirs with strong aquifer support. It is difficult to achieve a thorough and exact understanding of water drive gas reservoirs. It depends on several parameters of petrophysical and operational features. In majority of the previous studies about residual gas saturation, the correlations were depended on petrophysical properties such as porosity, permeability, and initial gas... 

    Controlling the properties of TiO2 nanoparticles generated by nanosecond laser ablation in liquid solution

    , Article Laser Physics ; Volume 28, Issue 8 , 2018 ; 1054660X (ISSN) Pashazadeh, M ; Irani, E ; Golzan, M. M ; Sadighi Bonabi, R ; Sharif University of Technology
    Institute of Physics Publishing  2018
    Laser ablation of titanium target in distilled water for synthesis of colloidal nanoparticles is studied both experimentally and theoretically. The effects of laser parameters such as wavelength, pulse energy, fluence and shot numbers on the ablation rate and size properties of colloidal nanoparticles are investigated. The experimental approach addresses the interesting issue for finding the optimal main experimental parameters of laser ablation. The theoretical thermal model of nanosecond pulsed laser ablation is developed to visualize the evolution of temperature distributions and ablation depth. The simulation result of ablation depth has been compared with the experimental result... 

    Development of an electrochemical sensor based on (rGO-CNT) nanocomposite for raloxifene analysis

    , Article Materials Chemistry and Physics ; Volume 263 , 2021 ; 02540584 (ISSN) Ghalkhani, M ; Shahrokhian, S ; Navabi, M ; Sharif University of Technology
    Elsevier Ltd  2021
    A novel modified electrode is reported for the electrochemical investigation of the oxidation mechanism and also voltammetric determination of raloxifene (RLX). The surface of the electrode was modified with a thin layer of reduced graphene oxide-carbon nanotube nano-composite (rGO-CNT) was prepared, and successfully employed for the electrochemical studies of RLX. The morphology of the sensor surface was characterized by using a scanning electron microscopy. RLX Oxidation response significantly increased at the GCE covered with rGO-CNT, regarding the bare and CNT or rGO functionalized GCE. Experimental parameters affecting the RLX response were optimized and mechanism of the RLX oxidation... 

    High temperature synthesis of SAPO-34: applying an L9 taguchi orthogonal design to investigate the effects of experimental parameters

    , Article Powder Technology ; Volume 217 , February , 2012 , Pages 223-230 ; 00325910 (ISSN) Dargahi, M ; Kazemian, H ; Soltanieh, M ; Hosseinpour, M ; Rohani, S ; Sharif University of Technology
    SAPO-34 zeolite-like particles were successfully synthesized at high temperature environment. An L9 orthogonal array of the Taguchi method was implemented to investigate the effects of experimental conditions to prepare SAPO-34 with respect to crystallinity of the final product phase. The results showed that the favorable phase crystallinity was improved by increasing the hydrothermal synthesis temperature and organic template content, whereas increasing the water content in synthesis mixture decreased the crystallinity. No significant changes in crystallinity of the final products were observed by increasing the synthesis duration. In addition, zeolite SAPO-5, which was formed as the... 

    Efficient removal of cationic dyes using a new magnetic nanocomposite based on starch-g-poly(vinylalcohol) and functionalized with sulfate groups

    , Article RSC Advances ; Volume 6, Issue 44 , 2016 , Pages 38042-38051 ; 20462069 (ISSN) Pourjavadi, A ; Abedin Moghanaki, A ; Tavakoli, A ; Sharif University of Technology
    Royal Society of Chemistry 
    A magnetic nanoparticle@starch-g-poly(vinyl sulfate) nanocomposite (MNP@St-g-PVS) as a new magnetic nano-adsorbent has been prepared based on graft copolymerization of vinyl acetate onto starch in the presence of magnetic nanoparticles, where the acetate groups were converted to hydroxyl groups followed by the sulfation of the hydroxyl groups using chlorosulfonic acid. Characterization of this magnetic nanocomposite was carried out by FTIR, TGA, XRD, VSM, SEM, TEM and elemental analysis. The resulting nanocomposite was used as an adsorbent for the removal of typical cationic dyes, methylene blue (MB) and malachite green (MG), from aqueous solutions. All experimental parameters that can... 

    Investigation of the electrochemical behavior of tizanidine on the surface of glassy carbon electrode modified with multi-walled carbon nanotube/titan yellow–doped polypyrrole

    , Article Journal of Electroanalytical Chemistry ; Volume 823 , 2018 , Pages 146-154 ; 15726657 (ISSN) Shahrokhian, S ; Shamloofard, M ; Salimian, R ; Sharif University of Technology
    The present paper describes a voltammetric sensor based on glassy carbon electrode (GCE) modified with a thin film of multi-walled carbon nanotubes (MWCNTs) coated with an electro-polymerized layer of titan yellow-doped over–oxidized polypyrrole (OPPY) for the determination of tizanidine (TIZ). A significant enhancement was observed in the anodic peak current of TIZ on the surface of OPPY/CNT/GCE, relative to the bare, CNT- and OPPY-coated GCEs. The microscopic structure and surface morphology of the composite film was thoroughly characterized by means of atomic force microscopy (AFM), scanning electron microscopy (SEM) and cyclic voltammetry (CV) techniques. The effect of various... 

    Effect of polymer content and temperature on mechanical properties of lightweight polymer concrete

    , Article Construction and Building Materials ; Volume 260 , 2020 Heidarnezhad, F ; Jafari, K ; Ozbakkaloglu, T ; Sharif University of Technology
    Elsevier Ltd  2020
    This study investigates the mechanical properties of lightweight polymer concrete (LWPC) containing four different polymer ratios (10%, 12%, 14%, and 16%) tested at three different temperatures (−15 °C, +5 °C, and +25 °C) using destructive and non-destructive tests. In addition, a series of expressions are suggested to predict the splitting-tensile, flexural and impact strength of LWPC based on the main parameters and compressive strength. The analysis of variance (ANOVA) method was also used to determine relative contributions of the experimental parameters. The results of the destructive tests show that increasing the polymer ratio caused an increase in the compressive, splitting-tensile,... 

    Silver nanowires immobilized on gold-modified glassy carbon electrode for electrochemical quantification of atorvastatin

    , Article Journal of Electroanalytical Chemistry ; Volume 876 , November , 2020 Naseri, A ; Hormozi Nezhad, M. R ; Shahrokhian, S ; Asadian, E ; Sharif University of Technology
    Elsevier B.V  2020
    Development of simple yet precise sensing platforms for rapid determination of biological species and drugs is of paramount importance, not only for analysis of pharmaceutical formulations during the production stage, but also in clinical practices and medical diagnosis. In the present research, we report on the electrochemical determination of atorvastatin (ATOR) by using silver nanowires/gold-modified glassy carbon electrode (Ag NWs/Au/GCE). The modified electrode was constructed through a two-step procedure in which narrow silver nanowires synthesized via a polyol method are drop casted on a pre-modified GCE with electrodeposited gold particles. The results of XRD analysis indicated the... 

    Electrochemical deposition of gold nanoparticles on carbon nanotube coated glassy carbon electrode for the improved sensing of tinidazole

    , Article Electrochimica Acta ; Volume 78 , September , 2012 , Pages 422-429 ; 00134686 (ISSN) Shahrokhian, S ; Rastgar, S ; Sharif University of Technology
    The electrochemical reduction of tinidazole (TNZ) is studied on gold-nanoparticle/carbon-nanotubes (AuNP/CNT) modified glassy carbon electrodes using the linear sweep voltammetry. An electrochemical procedure was used for the deposition of gold nanoparticles onto the carbon nanotube film pre-cast on a glassy carbon electrode surface. The resulting nanoparticles were characterized by scanning electron microscopy and cyclic voltammetry. The effect of the electrodeposition conditions, e.g., salt concentration and deposition time on the response of the electrode was studied. Also, the effect of experimental parameters, e.g., potential and time of accumulation, pH of the buffered solutions and... 

    Application of carbon nanoparticle/chitosan modified electrode for the square-wave adsorptive anodic striping voltammetric determination of Niclosamide

    , Article Electrochemistry Communications ; Volume 12, Issue 1 , 2010 , Pages 66-69 ; 13882481 (ISSN) Ghalkhani, M ; Shahrokhian, S ; Sharif University of Technology
    A new modified electrode formed by carbon nanoparticle/chitosan film (CNP/CS) was used for electrocatalytic reduction of Niclosamide (NA). The electrochemical behavior of NA at the CNP/CS modified electrode was investigated in detail by the means of cyclic voltammetry. The reduction mechanism of NA, corresponds to the redox chemistry of nitro group, was thoroughly investigated. The effect of the experimental parameters e.g. potential and time of accumulation, pH of the buffered solutions and potential sweep rate on the response of the electrode was studied. The prepared electrode showed high stability and uniformity in the composite film, short response time, good reproducibility and an... 

    Statistical, morphological, and corrosion behavior of PECVD derived cobalt oxide thin films

    , Article Journal of Materials Science: Materials in Electronics ; Volume 30, Issue 24 , 2019 , Pages 21185-21198 ; 09574522 (ISSN) Jafari, A ; Alam, M. H ; Dastan, D ; Ziakhodadadian, S ; Shi, Z ; Garmestani, H ; Weidenbach, A. S ; Ţălu, Ş ; Sharif University of Technology
    Springer  2019
    Experimental parameters have direct influences on materials properties and therefore their applications. The effect of plasma power on the properties of cobalt oxide thin films, prepared using plasma-enhanced chemical vapor deposition technique, on stainless steel substrates have been addressed in this paper. The structural, morphological, and compositional properties of these films were investigated by means of X-ray diffraction (XRD), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) technique. The XRD patterns demonstrated the growth of polycrystalline Co3O4 thin film with a cubic spinel structure such that the intensity of (511) and (311) peaks increase as the... 

    Facile template-free synthesis of new α-MnO2 nanorod/silver iodide p-n junction nanocomposites with high photocatalytic performance

    , Article New Journal of Chemistry ; Volume 44, Issue 18 , 2020 , Pages 7401-7411 Salari, H ; Kohantorabi, M ; Sharif University of Technology
    Royal Society of Chemistry  2020
    In the present study, a novel α-MnO2/AgI photocatalyst was successfully fabricated by using hydrothermal/precipitation methods, and its photocatalytic performance was evaluated from the degradation of Acid blue 92 (AB92) dye under visible light irradiation. The surface and crystalline structure, morphology, and electro-chemical properties of the as-made photocatalyst were investigated by BET, XRD, XPS, SEM-EDS, TEM, DRS, PL, PC, and Raman analysis. The optimized nanocomposite (α-MnO2/AgI) with a weight ratio of 1:15 showed the best photocatalytic activity in the decomposition of AB92 with a removal efficiency of 100% in 40 min which was better than that of pure α-MnO2 (48%) and AgI (61%),... 

    Voltammetric studies of sumatriptan on the surface of pyrolytic graphite electrode modified with multi-walled carbon nanotubes decorated with silver nanoparticles

    , Article Talanta ; Volume 80, Issue 1 , 2009 , Pages 31-38 ; 00399140 (ISSN) Ghalkhani, M ; Shahrokhian, S ; Ghorbani Bidkorbeh, F ; Sharif University of Technology
    Multi-walled carbon nanotube decorated with silver nanoparticles (AgNPs-MWCNT) is used as an effective strategy for modification of the surface of pyrolytic graphite electrode (PGE). This modification procedure improved colloidal dispersion of the decorated MWCNTs in water, affording uniform and stable thin films for altering the surface properties of the working electrode. Robust electrode for sensing applications is obtained in a simple solvent evaporation process. The electrochemical behavior of sumatriptan (Sum) at the bare PGE and AgNPs-MWCNT modified PGE is investigated. The results indicate that the AgNPs-MWCNT modified PGE significantly enhanced the oxidation peak current of Sum. A... 

    Optimization of some experimental parameters in the electro membrane extraction of chlorophenols from seawater

    , Article Journal of Chromatography A ; Volume 1216, Issue 45 , 2009 , Pages 7687-7693 ; 00219673 (ISSN) Lee, J ; Khalilian, F ; Bagheri, H ; Lee, H. K ; Sharif University of Technology
    An electro membrane extraction (EME) methodology was utilized to study the isolation of some environmentally important pollutants, such as chlorophenols, from aquatic media based upon the electrokinetic migration process. The analytes were transported by application of an electrical potential difference over a supported liquid membrane (SLM). A driving force of 10 V was applied to extract the analytes through 1-octanol, used as the SLM, into a strongly alkaline solution. The alkaline acceptor solution was subsequently analyzed by high performance liquid chromatography-ultraviolet (HPLC-UV) detection. The parameters influencing electromigration, including volumes and pH of the donor and... 

    Comparison between electrochemical and photoelectrochemical detection of dopamine based on titania-ceria-graphene quantum dots nanocomposite

    , Article Biosensors and Bioelectronics ; Volume 151 , 2020 Ahmadi, N ; Bagherzadeh, M ; Nemati, A ; Sharif University of Technology
    Elsevier Ltd  2020
    In this study, titania-ceria-graphene quantum dot (TC-GQD) nanocomposite was synthesized by hydrothermal method for the first time. The prepared nanomaterials were characterized by XRD, FTIR dynamic light scattering (DLS), FESEM, HRTEM, and EDX spectroscopy along with elemental mapping. The synergistic effect of the nanocomposite components was studied by diffuse reflectance spectroscopy (DRS) and electrical conductivity meter. The results showed that band gap of TC-GQD nanocomposite was shifted to visible lights relative to its components (1.3 eV), and electrical conductivity of the sample was significant increased to 89.5 μS cm−1. After chemical and physical characterization, prepared new...