Search for: surfactants
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    Prediction of critical micelle concentration of some anionic and cationic surfactants using an artificial neural network

    , Article Asian Journal of Chemistry ; Volume 19, Issue 4 , 2007 , Pages 2479-2489 ; 09707077 (ISSN) Fatemi, M. H ; Konuze, E ; Jalali Heravi, M ; Sharif University of Technology
    The critical micelle concentration (CMC) of a set of 58 alkylsulfates, alkylsulfonates, alkyltrimethyl ammonium and alkylpyridinium salts were predicted using an artificial neural network (ANN). The multiple linear regression (MLR) technique was used to select the important descriptors that act as inputs for artificial neural network. These descriptors are Balaban index, heat of formation, maximum distance between the atoms in the molecule, Randic index and volume of the molecule. Designed artificial neural network is a fully connected back-propagation network that has a 5-5-1 architecture. The results obtained using neural network were compared with those obtained using MLR technique.... 

    Studying the Mechanistic Behavior of Heavy Oil Displacement Using a Group of Alkalis and Surfactant Mixtures

    , Article Chemical Engineering Communications ; Vol. 202, issue. 3 , May , 2015 , p. 366-374 ; ISSN: 00986445 Dehghan, A. A ; Jadaly, A ; Masihi, M ; Ayatollahi, S ; Sharif University of Technology
    In this study, a mixture-based sulfonate-based surfactant with a novel formula capable of functioning in real oil reservoir conditions was prepared and some microscopic parameters, like its compatibility state, emulsion behavior, interfacial tension, and temperature dependency in the presence of a heavy oil sample, and two of the most popular alkalis were analyzed; then the results were compared with those of a commercial sulfate-based surfactant. The designed surfactant provided an optimum three-phase region in relatively high salinity media; however, its optimum value decreased when adding any alkaline materials; this trend was reversed for the solutions made with the sulfate-based... 

    Studying the mechanistic behavior of heavy oil displacement using a group of alkalis and surfactant mixtures

    , Article Chemical Engineering Communications ; Volume 202, Issue 3 , 2015 , Pages 366-374 ; 00986445 (ISSN) Dehghan, A. A ; Jadaly, A ; Masihi, M ; Ayatollahi, S ; Sharif University of Technology
    Taylor and Francis Ltd  2015
    In this study, a mixture-based sulfonate-based surfactant with a novel formula capable of functioning in real oil reservoir conditions was prepared and some microscopic parameters, like its compatibility state, emulsion behavior, interfacial tension, and temperature dependency in the presence of a heavy oil sample, and two of the most popular alkalis were analyzed; then the results were compared with those of a commercial sulfate-based surfactant. The designed surfactant provided an optimum three-phase region in relatively high salinity media; however, its optimum value decreased when adding any alkaline materials; this trend was reversed for the solutions made with the sulfate-based... 

    Colloidal gold nanoparticles: an unexpected catalytic activity in aqueous phase with dioxygen

    , Article catalysis letters ; Volume 144, Issue 7 , July , 2014 , pp. 1219-1222 ; 1572-879X Salari, H. (Hadi) ; Robatjazi, H. (Hossein) ; Hormozi-Nezhad, M. (Mohammad Reza) ; Padervand, M. (Mohsen) ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
    Selective oxidations of alkenes were investigated using molecular oxygen in aqueous solution under mild conditions. Colloidal gold nanoparticles are particularly versatile catalysts for oxidation reaction with exceptionally high efficiency and significant selectivity. Gold nanorods (Au NRs) exhibited a slightly enhanced activity compare to gold nanospheres  

    A pore-level investigation of surfactant-crude oil displacements behavior in fractured porous media using one-quarter five spot micromodels

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, issue. 7 , April , 2014 , pp. 727-737 ; ISSN: 15567036 Kianinejad, A ; Rashtchian, D ; Ghazanfari, M. H ; Kharrat, R ; Sharif University of Technology
    Despite numerous studies, there is a lack of fundamental understanding about the displacement behavior of surfactant-crude oil systems under the influence of different fractures' geometrical properties in five-spot systems. In this work, a series of flow visualization experiments were carried out on one-quarter five spot glass micromodels at various fractures' geometrical properties, such as fracture density and fracture continuity, under oil-wet condition. The influences of injection of Linear Alkyl Benzene Sulfonate and Sodium Dodecyl Sulfate surfactants as well as the effect of fracture geometrical parameters, on macroscopic and microscopic displacement behavior have been investigated.... 

    The impact of surfactants on wettability change and level of water imbibition in relation to EOR in carbonate reservoirs

    , Article Petroleum Science and Technology ; Volume 31, Issue 20 , 2013 , Pages 2098-2109 ; 10916466 (ISSN) Zangeneh Var, A ; Bastani, D ; Badakhshan, A ; Sharif University of Technology

    Recovery of surfactants from oil in water emulsions by electroflotation

    , Article 8th World Congress of Chemical Engineering: Incorporating the 59th Canadian Chemical Engineering Conference and the 24th Interamerican Congress of Chemical Engineering, 23 August 2009 through 27 August 2009, Montreal, QC ; 2009 Biria, D ; Mansouri, M ; Maghsoudi, E ; Roostaazad, R ; Dadafarin, H ; Sharif University of Technology
    An electroflotation technique was utilized to reclaim the surfactant molecules from oil-in-water emulsions. A two-staged separation mechanism was suggested to describe the process. The surfactant recovery efficiencies were higher than 70% after 30 min treatment. The method could be an effective process in recycling surfactants from the emulsions existing in industrial wastes. This is an abstract of a paper presented at the 8th World Congress of Chemical Engineering (Montreal, Quebec, Canada 8/23-27/2009)  

    CFD simulation of bubble in flow field: Investigation of dynamic interfacial behaviour in presence of surfactant molecules

    , Article Colloids and Interface Science Communications ; Volume 27 , 2018 , Pages 1-10 ; 22150382 (ISSN) Bastani, D ; Fayzi, P ; Lotfi, M ; Arzideh, S. M ; Sharif University of Technology
    Elsevier B.V  2018
    This work presents the results of numerical simulation of liquid flow on a static bubble. Velocity and surfactant concentration profiles of the liquid around a bubble exposed in flow field were estimated via unsteady CFD solution. Governing equations are the Navier-Stokes and conservation of mass in the liquid bulk and at the interface. Resulted profiles of surfactant concentration and velocity in the liquid bulk are used to determine the dynamic surface tension data via two adsorption isotherms of Langmuir and Frumkin. Data of dynamic surface tension were validated via experimental data of “bubble in flow field” protocol. Surface concentrations of surfactants were also numerically... 

    Surfactant production by an enzymatic method

    , Article Enzyme and Microbial Technology ; Volume 33, Issue 1 , 2003 , Pages 33-37 ; 01410229 (ISSN) Tarahomjoo, S ; Alemzadeh, I ; Sharif University of Technology
    Elsevier Inc  2003
    Glucose was acylated with palmitic acid using two kinds of lipases. The reactions were performed in the presence of an organic solvent. Solvent effect and molecular sieve effect and also the effect of enzyme amount and influence of molar ratio of substrates on glucose palmitate production with lipase from Rhizomucor miehei (Palatase® M) were studied. Application of molecular sieves together with open system increased palmitic acid conversion in the reaction mixture. Glucose palmitate was obtained in 41.18% conversion in hexane at 40°C with Palatase® M. Glucose palmitate was also synthesized with lipase from Candida antarctica (Novozyme 435). Esterification of palmitic acid with glucose... 

    Synergistic effect of like and opposite charged nanoparticle and surfactant on foam stability and mobility in the absence and presence of hydrocarbon: a comparative study

    , Article Journal of Petroleum Science and Engineering ; Volume 166 , July , 2018 , Pages 433-444 ; 09204105 (ISSN) Veyskarami, M ; Ghazanfari, M. H ; Sharif University of Technology
    Elsevier B.V  2018
    The aim of this study is to compare the synergistic impact of like and opposite-charged nanoparticle and surfactant systems on enhancing stability and mobility of foam in the absence and presence of oil which is not sufficiently discussed in the available literature. Stability of nanoparticle dispersion is examined at various levels of pH when nanoparticle and surfactant are in like and opposite-charged conditions. In situ modification of silica nanoparticle by opposite-charged surfactant is analyzed. Static stability tests as well as Hele–Shaw cell are employed to understand how nanoparticle and surfactant charges may control the stability and mobility of foam when oil is present/absent.... 

    Influence of β-lactoglobulin and its surfactant mixtures on velocity of the rising bubbles

    , Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Vol. 460 , October , 2014 , pp. 361-368 ; ISSN: 09277757 Ulaganathan, V ; Krzan, M ; Lotfi, M ; Dukhin, S. S ; Kovalchuk, V. I ; Javadi, A ; Gunes, D. Z ; Gehin-Delval, C ; Malysa, K ; Miller, R ; Sharif University of Technology
    The rising velocity of air bubbles in surfactant solutions is a sensitive measure for the formation of a dynamic adsorption layer (DAL) at the bubble surface. Due to a certain surface coverage by adsorbed species the bubble surface starts to become immobilized and the rising velocity is retarded. There is a large difference in the retardation effect in presence of the protein β-lactoglobulin (BLG) alone and its mixed solutions with surfactants. In presence of added surfactants BLG forms complexes, which adsorb and retard the bubble rising velocity according to their respective surface activity and adsorption kinetics. While the nonionic surfactant C12DMPO does not show significant increase... 

    Experimental study of nanoparticle-surfactant-stabilized CO2 foam: Stability and mobility control

    , Article Chemical Engineering Research and Design ; Volume 111 , 2016 , Pages 449-460 ; 02638762 (ISSN) Farhadi, H ; Riahi, S ; Ayatollahi, S ; Ahmadi, H ; Sharif University of Technology
    Institution of Chemical Engineers  2016
    CO2 injection has proved to be the most common and efficient enhanced oil recovery techniques which leads to more residual oil recovery. Unfavorable sweep efficiency which results in fingering propagation and causes early gas breakthrough is the most challenging issue of gas flooding process. The aim of this work is to study foam stability and analyze the mobility of CO2 foam stabilized by mixture of raw silica nanoparticles and ethyl hexadecyl dimethyl ammonium bromide (cationic surfactant). The result is obtained through both dynamic and static techniques using a new adsorption index.NPS-stabilized foams are generated using Ross-Miles method. A novel index for the adsorption of surfactant... 

    Investigating the synergic effects of chemical surfactant (SDBS) and biosurfactant produced by bacterium (Enterobacter cloacae) on IFT reduction and wettability alteration during MEOR process

    , Article Journal of Molecular Liquids ; Volume 256 , 2018 , Pages 277-285 ; 01677322 (ISSN) Hajibagheri, F ; Hashemi, A ; Lashkarbolooki, M ; Ayatollahi, S ; Sharif University of Technology
    Elsevier B.V  2018
    In the current study, a novel approach which takes into account the effectiveness of both convectional surfactants and biosurfactants was investigated. The biosurfactant produced by Enterobacter cloacae strain was utilized concomitant with conventional surfactant (sodium dodecyl benzene sulfonate (SDBS)) to evaluate its capability to reduce the SDBS adsorption on rock surface (biosurfactant acts as sacrificial agent) or synergistically enhance the effectiveness of the SDBS. In this regard, the wettability alteration and interfacial tension (IFT) measurements and calculation of spreading coefficient were performed considering two different scenarios. In the first scenario, SDBS was added to... 

    A note on the synergistic effect of surfactants and nanoparticles on rising bubble hydrodynamics

    , Article Chemical Engineering and Processing - Process Intensification ; Volume 155 , 2020 Fayzi, P ; Bastani, D ; Lotfi, M ; Sharif University of Technology
    Elsevier B.V  2020
    Various mixtures of surfactants and nanosilica particles were investigated to assess their influence on rising bubble hydrodynamics. For this purpose, local velocities of rising bubbles were measured experimentally. Also, the effects of concentration of three types of surface-modified silica nanoparticles on density, viscosity, and surface tension of surfactant solutions were determined. Experimental results revealed that the simultaneous presence of nanoparticles and surfactant molecules led to the decrease of local velocities of rising bubbles. The presence of nanoparticles in surfactant solutions leads to a more reduction of bubble local velocity. This could be caused by the formation of... 

    Influences of polymer-surfactant interaction on the drop formation process: an experimental study

    , Article Langmuir ; Volume 37, Issue 3 , 2021 , Pages 1025-1036 ; 07437463 (ISSN) Dastyar, P ; Salehi, M. S ; Firoozabadi, B ; Afshin, H ; Sharif University of Technology
    American Chemical Society  2021
    The interaction between polymer and surfactant molecules affects the physical properties of liquids, which could be of great importance in an abundance of processes related to drop formation. Polymer and surfactant concentration is a factor that dramatically impacts the shape of molecular networks formed in the fluid bulk and the characteristics of a forming drop. In this study, the deformation and detachment of aqueous carboxymethyl cellulose (CMC) solutions' drops containing different concentrations of sodium dodecyl sulfate (SDS) are studied experimentally. Our purpose is to determine the effects of CMC and SDS concentrations on the parameters related to the formation process, including... 

    The effect of polymeric surfactant content on the mechanical properties of Al/GNP nanocomposites

    , Article Materials Chemistry and Physics ; Volume 257 , 2021 ; 02540584 (ISSN) Moradi, M ; Abouchenari, A ; Pudine, M ; Sharifianjazi, F ; Sharif University of Technology
    Elsevier Ltd  2021
    Graphene nanoplatelets (GNPs) are ideal reinforcements for improving the mechanical properties of aluminum-based matrices due to their outstanding properties. However, it essentially depends on their uniform dispersion in the matrix. In this study, the challenge of uniform dispersion of graphene was performed by functionalizing the non-covalent surface and sonication of GNPs applying non-ionic polymeric ethyl cellulose (EC) surfactant, in which a colloidal mixture was provided with Al powder and graphene, followed by sintering at 620 °C and consolidation. The density and mechanical properties of nanocomposite specimens were investigated and compared with a non-surfactant-assisted Al/GNP... 

    Qualitative Study of the Dynamic Adsorption Layer by Bubble Rising Method

    , M.Sc. Thesis Sharif University of Technology Bahmani, Alireza (Author) ; Bastani, Dariush (Supervisor) ; Lotfi, marzieh (Co-Advisor)
    Surface phenomena and dynamic interfacial properties plays a significant role in multiphase gas-liquid & liquid-liquid processes applied in different industrial applications. However, current laboratory equipment and represented methods for dynamic and unsteady state condition caused by motivation of interface of two phases (like rising bubble), in purpose of qualitative investigation of interphase properties are not satisfying enough. Also, common modeling methods are represented with lots of modified assumptions which are not validated properly with experimental results. In current thesis, with development of laboratory tools and applying the “rising bubble method” for investigating the... 

    Experimental Study of Partitioning of Lysozyme Enzyme in Aqueous Two-Phase Systems based on Surfactants

    , M.Sc. Thesis Sharif University of Technology Barjasteh, Mahdi (Author) ; Bastani, Dariush (Supervisor) ; Vosoughi, Manochehr (Supervisor)
    In this study, aqueous two-phase systems (ATPS) containing Tween 20 as a biocompatible nonionic surfactant and three different salts (NH4HPO4, NH4CH3COO and Mg(CH3COO)2 ) were prepared and their extractive potential for Lysozyme enzyme was evaluated. These systems have surfactant-rich top phase and salt-rich bottom phase. Phase equilibrium diagrams at 23 ° C were obtained by using the cloud point method and the results were successfully fitted to the Merchuk correlation and their trends were correlated with the effective excluded volume (EEV) parameter. Afterward, the partitioning behavior of the lysozyme and its extraction efficiency in the systems of Tween 20/diammonium hydrogen phosphate,... 

    Experimental Investigation of Surfactant Flooding for EOR in Layered Heavy Oil Reservoirs using Micromodel Apparatus

    , M.Sc. Thesis Sharif University of Technology Morshedi, Saeid (Author) ; Rashtchian, Davood (Supervisor) ; Massihi, Mohsen (Supervisor) ; Ghazanfari, Mohammad Hossein (Supervisor)
    Nowadays, due to limitation of production from conventional oil reservoirs, enhanced recovery from heavy oil reservoirs are of great concern. In heavy oil reservoirs, only 5% of initial oil in place (IOIP) is producible due to high viscosity. Water flooding increases oil recovery just up to 10% which is due to improper mobility ratio. One of popular methods for increasing oil recovery is injection of chemical materials. Chemical methods are used in reservoirs that have high degree of heterogeneity like heterogeneous and layered reservoirs. These heterogeneities cause diversion and loss of injected water which leads to remaining of oil in its place. Using surface active agents, as a popular... 

    Study of the Effect of Surfactant and Fe Concentration on the Size and Physical Properties of Magnetic Fe-Au Core-Shell Nano Particles, Synthesized Via Reverse Nicelle

    , M.Sc. Thesis Sharif University of Technology Molavi Kakhki, Amin (Author) ; Simchi, Abdolreza (Supervisor) ; Abachi, Parvin (Supervisor)
    The aim of this research is to study the effect of surfactant type and the concentration reactants on the size, shape and magnetic properties of iron-gold core-shell magnetic nanoparticles (NPs) useable for biomedical application. The reverse micelle procedure was employed to synthesize iron NPs using two surfactants of CTAB and SDS. A gold shell with a thickness in the range of 10 to 40 nm was induced by reverse micelle method in order to prevent oxidation of the iron core. The size and morphology of NPs were studied by transition electron microscopy (TEM). It was found that the size of NPs increases by the increasing the reactants concentration while the morphology of the NPs was not...