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    Mechanistic study of wettability alteration of oil-wet calcite: The effect of magnesium ions in the presence and absence of cationic surfactant

    , Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 482 , October , 2015 , Pages 403-415 ; 09277757 (ISSN) Karimi, M ; Al Maamari, R. S ; Ayatollahi, S ; Mehranbod, N ; Sharif University of Technology
    Elsevier  2015
    Abstract
    Over 60% of the world's discovered oil reserves are held in carbonate reservoirs, which are mostly naturally fractured. Conventional water flooding results in low oil recovery efficiency in these reservoirs as most of them are oil-wet. On account of negative capillary forces, injected brine cannot penetrate simply into an oil-wet matrix of fractured formations to force the oil out. Wettability alteration of the rock surface to preferentially more water-wet state has been extensively studied using both smart water and surfactants separately. This study aims to study the effects of Mg2+ as one of the most important wettability influencing ions on the wetting properties of oil-wet carbonate... 

    Synthesis and characterization of MoO3 nanostructures by solution combustion method employing morphology and size control

    , Article Journal of Nanoparticle Research ; Volume 12, Issue 4 , 2010 , Pages 1509-1521 ; 13880764 (ISSN) Parviz, D ; Kazemeini, M ; Rashidi, A. M ; Jafari Jozani, Kh ; Sharif University of Technology
    Abstract
    Molybdenum oxide nanostructures were synthesized utilizing the solution combustion method where the ammonium molybdate powder and an organic additive were used as precursors. Different organic additives including ethylene diamine tetraacetic acid (EDTA), polyethylene glycol 200 (PEG 200), sorbitol and urea were used as surfactants in order to investigate the effect of additive structure on morphology and particle size of products. Also various reaction parameters such as the additive/Mo molar ratio, concentration of metal ion in solution, pH of the reaction, and temperature of the synthesis media were changed to study effects on product morphology and size. Outcomes were characterized by... 

    Development of a novel method for determination of mercury based on its inhibitory effect on horseradish peroxidase activity followed by monitoring the surface plasmon resonance peak of gold nanoparticles

    , Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 153 , 2016 , Pages 709-713 ; 13861425 (ISSN) Khodaveisi, J ; Haji Shabani, A. M ; Dadfarnia, S ; Rohani Moghadam, M. R ; Hormozi Nezhad, M. R ; Sharif University of Technology
    Elsevier 
    Abstract
    A highly sensitive and simple indirect spectrophotometric method has been developed for the determination of trace amounts of inorganic mercury (Hg2 +) in aqueous media. The method is based on the inhibitory effect of Hg2 + on the activity of horseradish peroxidase (HRP) in the oxidation of ascorbic acid by hydrogen peroxide followed by the reduction of Au3 + to Au-NPs by unreacted ascorbic acid and the measurement of the absorbance of localized surface plasmon resonance (LSPR) peak of gold nanoparticles (at 530 nm) which is directly proportional to the concentration of Hg2 +. Under the optimum conditions, the calibration curve was linear in the concentration range of 1-220 ng mL- 1. Limits... 

    Nickel-cobalt layered double hydroxide ultrathin nanosheets coated on reduced graphene oxide nonosheets/nickel foam for high performance asymmetric supercapacitors

    , Article International Journal of Hydrogen Energy ; 2017 ; 03603199 (ISSN) Shahrokhian, S ; Rahimi, S ; Mohammadi, R ; Sharif University of Technology
    Elsevier Ltd  2017
    Abstract
    Here in, for the first time, we report a new and simple procedure for preparing reduced graphene oxide/nickel-cobalt double layered hydroxide composite on the nickel foam (Ni-Co LDH/rGO/NF) via a fast and simple two-step electrochemical method including potentiostatic routes in the presence of CTAB as a cationic surfactant. Graphene oxide coated nickel foam prepared by simple immersion method. After that, the prepared electrode reduced electrochemically to obtain rGO/NF electrode. Finally, the rGO/NF electrode was used as cathode for electrodeposition of Ni-Co LDH in the presence of CTAB as cationic surfactant. The prepared electrodes were characterized by field emission scanning electron... 

    Vertically standing Cu2O nanosheets promoted flower-like PtPd nanostructures supported on reduced graphene oxide for methanol electro-oxidation

    , Article Electrochimica Acta ; Volume 259 , 2018 , Pages 36-47 ; 00134686 (ISSN) Shahrokhian, S ; Rezaee, S ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    The present study reports a simple electrochemical approach to the fabrication of a new nanocomposite containing PtPd nanoflowers (NFs) promoted with two-dimensional (2D) nanosheets (NSs) structure cuprous oxide (Cu2O) supported on reduced graphene oxide (rGO) (PtPd-NFs/Cu2O-NSs/rGO). Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectra, Raman spectroscopy, and energy dispersive X-ray spectroscopy are used for characterization of the PtPd-NPs/Cu2O-NPs/rGO. SEM images showed that vertical-standing arrays of Cu2O with an edge length up to 1 μm and thickness of about 20 nm are electrodeposited on the surface of rGO film. Also, PtPd needle-like NFs with visible and... 

    Nickel-cobalt layered double hydroxide ultrathin nanosheets coated on reduced graphene oxide nonosheets/nickel foam for high performance asymmetric supercapacitors

    , Article International Journal of Hydrogen Energy ; Volume 43, Issue 4 , 2018 , Pages 2256-2267 ; 03603199 (ISSN) Shahrokhian, S ; Rahimi, S ; Mohammadi, R ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    Here in, for the first time, we report a new and simple procedure for preparing reduced graphene oxide/nickel-cobalt double layered hydroxide composite on the nickel foam (Ni-Co LDH/rGO/NF) via a fast and simple two-step electrochemical method including potentiostatic routes in the presence of CTAB as a cationic surfactant. Graphene oxide coated nickel foam prepared by simple immersion method. After that, the prepared electrode reduced electrochemically to obtain rGO/NF electrode. Finally, the rGO/NF electrode was used as cathode for electrodeposition of Ni-Co LDH in the presence of CTAB as cationic surfactant. The prepared electrodes were characterized by field emission scanning electron... 

    Template-directed hydrothermal synthesis of dandelion-like hydroxyapatite in the presence of cetyltrimethylammonium bromide and polyethylene glycol

    , Article Ceramics International ; Volume 35, Issue 7 , 2009 , Pages 2563-2569 ; 02728842 (ISSN) Salarian, M ; Solati Hashjin, M ; Shafiei, S. S ; Salarian, R ; Nemati, Z. A ; Sharif University of Technology
    2009
    Abstract
    A template-directed synthetic method, using surfactant cetyltrimethylammonium bromide (CTAB) as a template and co-surfactant polyethylene glycol (PEG600) as a co-template under hydrothermal conditions, has been applied to obtain dandelion-like HAp. The morphology, size, crystalline phase, chemical composition, physical characteristics, and thermal behavior of the product were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier ransform infrared spectroscopy (FTIR), induced coupled plasma spectroscopy (ICP), BET (Brunauer, Emmett, and Teller) method, and simultaneous thermal analysis (STA). SEM and TEM... 

    Surfactant-free stable SnS2 nanoparticles dispersion for deposition of device-quality films

    , Article Thin Solid Films ; Volume 669 , 2019 , Pages 269-274 ; 00406090 (ISSN) Haghighi, M ; Tajabadi, F ; Mahdavi, S. M ; Mohammadpour, R ; Taghavinia, N ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    Tin sulfide (SnS2) has recently attracted considerable attention due to its layered structure that may form two dimensional morphologies. It is an n-type semiconductor with band gap and electron affinity similar to CdS and In2S3; therefore can be regarded as an alternative for these materials in thin film solar cells. Here, we synthesis of SnS2 nanoparticles with different morphology in different ratio of water-ethanol mixed solution by solvothermal method, and observe that more ethanol leads to large sheet like morphologies, while water based synthesis results in very small nanosheets. A challenge in wet deposition of device-quality thin films of SnS2 is the requirement for highly dispersed... 

    Niosomal formulation for antibacterial applications

    , Article Journal of Drug Targeting ; Volume 30, Issue 5 , 2022 , Pages 476-493 ; 1061186X (ISSN) Mehrarya, M ; Gharehchelou, B ; Haghighi Poodeh, S ; Jamshidifar, E ; Karimifard, S ; Farasati Far, B ; Akbarzadeh, I ; Seifalian, A ; Sharif University of Technology
    Taylor and Francis Ltd  2022
    Abstract
    Infection is a disease that is mainly caused by different Gram-negative and Gram-positive bacteria. Treatment of infections requires a considerable amount of antibiotics, which can cause serious damage to the patient's body. Delivering the antibiotic only to the site of infection can prevent these destructive effects, such as the destruction of the normal intestinal flora. The drug delivery system through carriers will take antibiotics into a part of the body involved in the disease. Niosome nanoparticles, which have been made from non-ionic surfactants, have been emerging as ideal drug/antibiotics delivery vehicles. Recently, niosome formulations have been targeted to reduce toxicity and... 

    Dissolution and remobilization of NAPL in surfactant-enhanced aquifer remediation from microscopic scale simulations

    , Article Chemosphere ; Volume 289 , 2022 ; 00456535 (ISSN) Ramezanzadeh, M ; Aminnaji, M ; Rezanezhad, F ; Ghazanfari, M. H ; Babaei, M ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    In this paper, the dissolution and mobilization of non-aqueous phase liquid (NAPL) blobs in the Surfactant-Enhanced Aquifer Remediation (SEAR) process were upscaled using dynamic pore network modeling (PNM) of three-dimensional and unstructured networks. We considered corner flow and micro-flow mechanisms including snap-off and piston-like movement for two-phase flow. Moreover, NAPL entrapment and remobilization were evaluated using force analysis to develop the capillary desaturation curve (CDC) and predict the onset of remobilization. The corner diffusion mechanism was also applied in the modeling of interphase mass transfer to represent NAPL dissolution as the dominant mass transfer... 

    Synthesis and cytotoxicity assessment of superparamagnetic iron-gold core-shell nanoparticles coated with polyglycerol

    , Article Journal of Colloid and Interface Science ; Volume 345, Issue 1 , 2010 , Pages 64-71 ; 00219797 (ISSN) Jafari, T ; Simchi, A ; Khakpash, N ; Sharif University of Technology
    Abstract
    Core-shell iron-gold (Fe@Au) nanoparticles were synthesized by a facile reverse micelle procedure and the effect of water to surfactant molar ratio (w) on the size, size distribution and magnetic properties of the nanoparticles was studied. MTT assay was utilized to evaluate the cell toxicity of the nanoparticles. To functionalize the particles for MRI imaging and targeted drug delivery, the particles were coated by polyglycerol through capping with thiol followed by polymerization of glycidol. The characteristics of the particles were examined by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometere (VSM), UV-visible spectroscopy, and Fourier... 

    A novel needle trap sorbent based on carbon nanotube-sol-gel for microextraction of polycyclic aromatic hydrocarbons from aquatic media

    , Article Analytica Chimica Acta ; Volume 683, Issue 2 , January , 2011 , Pages 212-220 ; 00032670 (ISSN) Bagheri, H ; Ayazi, Z ; Aghakhani, A ; Sharif University of Technology
    2011
    Abstract
    A new type of composite material based on carbon nanotubes (CNTs) and sol-gel chemistry was prepared and used as sorbent for needle trap device (NTD). The synthesized composite was prepared in a way to disperse CNTs molecules in a sol-gel polymeric network. CNT/silica composites with different CNT doping levels were successfully prepared, and the extraction capability of each composite was evaluated. Effects of surfactant and the oxidation duration of CNTs on the extraction efficiency of synthesized composites were also investigated. The applicability of the synthesized sorbent was examined by developing a method based on needle trap extraction (NTE) and gas chromatography mass spectrometry... 

    Structural characterization of a rhamnolipid-type biosurfactant produced by Pseudomonas aeruginosa MR01: Enhancement of di-rhamnolipid proportion using gamma irradiation

    , Article Colloids and Surfaces B: Biointerfaces ; Volume 81, Issue 2 , 2010 , Pages 397-405 ; 09277765 (ISSN) Lotfabad, T. B ; Abassi, H ; Ahmadkhaniha, R ; Roostaazad, R ; Masoomi, F ; Zahiri, H. S ; Ahmadian, G ; Vali, H ; Noghabi, K. A ; Sharif University of Technology
    2010
    Abstract
    We previously reported that MR01, an indigenous strain of Pseudomonas aeruginosa, was able to produce a rhamnolipid-type biosurfactant. Here, we attempted to define the structural properties of this natural product. The analysis of the extracted biosurfactant by thin-layer chromatography (TLC) revealed the presence of two compounds corresponding to those of authentic mono- and di-rhamnolipid. The identity of two structurally distinguished rhamnolipids was confirmed by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. Liquid chromatography/mass spectrometry (LC/MS) of extracted biosurfactant revealed up to seventeen different rhamnolipid congeners. Further quantification showed... 

    Genome annotation and comparative genomic analysis of Bacillus subtilis MJ01, a new bio-degradation strain isolated from oil-contaminated soil

    , Article Functional and Integrative Genomics ; Volume 18, Issue 5 , 2018 , Pages 533-543 ; 1438793X (ISSN) Rahimi, T ; Niazi, A ; Deihimi, T ; Taghavi, S. M ; Ayatollahi, S ; Ebrahimie, E ; Sharif University of Technology
    Springer Verlag  2018
    Abstract
    One of the main challenges in elimination of oil contamination from polluted environments is improvement of biodegradation by highly efficient microorganisms. Bacillus subtilis MJ01 has been evaluated as a new resource for producing biosurfactant compounds. This bacterium, which produces surfactin, is able to enhance bio-accessibility to oil hydrocarbons in contaminated soils. The genome of B. subtilis MJ01 was sequenced and assembled by PacBio RS sequencing technology. One big contig with a length of 4,108,293 bp without any gap was assembled. Genome annotation and prediction of gene showed that MJ01 genome is very similar to B. subtilis spizizenii TU-B-10 (95% similarity). The comparison... 

    Reinforced polydiphenylamine nanocomposite for microextraction in packed syringe of various pesticides

    , Article Journal of Chromatography A ; Volume 1222 , January , 2012 , Pages 13-21 ; 00219673 (ISSN) Bagheri, H ; Ayazi, Z ; Es'haghi, A ; Aghakhani, A ; Sharif University of Technology
    2012
    Abstract
    Reinforced polydiphenylamine (PDPA) nanocomposite was synthesized by oxidation of diphenylamine in 4molL-1 sulfuric acid solution containing a fixed amount of carbon nanotubes (CNTs) in the presence of cetyltrimethylammonium bromide (CTAB). The surface characteristic of PDPA and PDPA/CNT nanocomposites was investigated using scanning electron microscopy (SEM). The prepared PDPA/CNT nanocomposite was used as an extraction medium for microextraction in packed syringe (MEPS) of selected pesticides from aquatic environment. The effect of CNT doping level and the presence of surfactant on the extraction capability of nanocomposite was investigated and it was revealed that when 4% (w/w) of CNT in...