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A core–shell titanium dioxide polyaniline nanocomposite for the needle-trap extraction of volatile organic compounds in urine samples
, Article Journal of Separation Science ; Volume 40, Issue 9 , 2017 , Pages 1985-1992 ; 16159306 (ISSN) ; Bagheri, H ; Sharif University of Technology
Wiley-VCH Verlag
2017
Abstract
We synthesized a titanium dioxide–polyaniline core–shell nanocomposite and implemented it as an efficient sorbent for the needle-trap extraction of some volatile organic compounds from urine samples. Polyaniline was synthesized, in the form of the emeraldine base, dissolved in dimethyl acetamide followed by diluting with water at pH 2.8, using the interfacial polymerization method. The TiO2 nanoparticles were encapsulated inside the conducting polymer shell, by adapting the in situ dispersing approach. The surface characteristics of the nanocomposite were investigated by Fourier transform infrared spectrometry, scanning electron microscopy, and transmission electron microscopy. After...
Microwave-assisted extraction and high-throughput monolithic-polymer-based micro-solid-phase extraction of organophosphorus, triazole, and organochlorine residues in apple
, Article Journal of Separation Science ; Volume 39, Issue 3 , 2016 , Pages 576-583 ; 16159306 (ISSN) ; Es Haghi, A ; Basiri Pour, F ; Sharif University of Technology
Wiley-VCH Verlag
Abstract
A high-throughput micro-solid-phase extraction device based on a 96-well plate was constructed and applied to the determination of pesticide residues in various apple samples. Butyl methacrylate and ethylene glycol dimethacrylate were copolymerized as a monolithic polymer and placed in the cylindrically shaped stainless-steel meshes of 96-micro-solid-phase extraction device and used as an extracting unit. Before the micro-solid-phase extraction, microwave-assisted extraction was employed to facilitate the transfer of the pesticide residues from the apple matrix to liquid media. Then, 1 mL of the aquatic samples was transferred into the 96-well plate and the 96-micro-solid-phase extraction...
Experimental investigation of dynamic asphaltene adsorption on calcite packs: The impact of single and mixed-salt brine films
, Article Canadian Journal of Chemical Engineering ; Volume 97, Issue 7 , 2019 , Pages 2028-2038 ; 00084034 (ISSN) ; Ghotbi, C ; Jafari Behbahani, T ; Bakhshi, P ; Sharif University of Technology
Wiley-Liss Inc
2019
Abstract
In this study, the dynamic adsorption of asphaltene on a calcite surface is investigated. This study investigates the effect of mixed-salt brines on asphaltene adsorption. The results of this work can facilitate the understanding of the complex wettability behaviour of carbonate reservoirs. All experiments were performed in porous media, which were sand-packs filled with calcite powder, to study the influence of the type and concentration of salt on adsorption. The experiments were conducted with asphaltene concentration of 500 mg/L for brines of NaCl, Na2SO4, and a mixture of the two at various ionic strengths. In addition, two tests were performed with an asphaltene concentration of 2000...
Evaluation of partial least-squares regression with multivariate analytical figures of merit for determination of 10 pesticides in milk
, Article International Journal of Environmental Analytical Chemistry ; March , 2020 ; Balsini, P ; Parastar, H ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
A multi-residue method using gas chromatography coupled with flame ionisation detector has been developed for simultaneous determination of 10 pesticides in milk. The methodology involved a sample clean-up procedure using ‘quick, easy, cheap, effective, rugged and safe’ followed by a preconcentration step based on dispersive liquid–liquid microextraction. In this regard, acetonitrile was added to the milk sample with specific pH and ionic strength, and the mixture was rigorously shaken. The extracts were centrifuged; then, the organic phase (acetonitrile) was transferred to a test tube and was mixed with deionised water. The mixture was sonicated and chloroform was added as an acceptor phase...
Evaluation of partial least-squares regression with multivariate analytical figures of merit for determination of 10 pesticides in milk
, Article International Journal of Environmental Analytical Chemistry ; Volume 102, Issue 8 , 2022 , Pages 1900-1910 ; 03067319 (ISSN) ; Balsini, P ; Parastar, H ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
A multi-residue method using gas chromatography coupled with flame ionisation detector has been developed for simultaneous determination of 10 pesticides in milk. The methodology involved a sample clean-up procedure using ‘quick, easy, cheap, effective, rugged and safe’ followed by a preconcentration step based on dispersive liquid–liquid microextraction. In this regard, acetonitrile was added to the milk sample with specific pH and ionic strength, and the mixture was rigorously shaken. The extracts were centrifuged; then, the organic phase (acetonitrile) was transferred to a test tube and was mixed with deionised water. The mixture was sonicated and chloroform was added as an acceptor phase...
Investigation of rock and fluid interactions during engineered water flooding in dolomite reservoir rocks
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; 2020 ; Masihi, M ; Safekordi, A. A ; Ayatollahi, S ; Sadeghnejad, S ; Sharif University of Technology
Taylor and Francis Inc
2020
Abstract
Engineered water (EW) flooding is one of the enhanced oil recovery (EOR) techniques in carbonate reservoirs. In this method, the wettability of reservoir rock is altered by controlling the amount of various ions in the injected brine. The thermodynamics of wettability is related to the surface interactions and stability of water film on a rock surface. It can be identified by calculating disjoining pressure isotherms. In this study, core flooding tests, contact angle and zeta potential measurements along with the disjoining pressure isotherm calculation by the DLVO theory were used to investigate the wettability alteration of dolomite rock. Four brines include reservoir formation water...
Transport in droplet-hydrogel composites: response to external stimuli
, Article Colloid and Polymer Science ; Volume 293, Issue 3 , March , 2015 , Pages 941-962 ; 0303402X (ISSN) ; Sharif University of Technology
Springer Verlag
2015
Abstract
Determination of effective transport properties of droplet-hydrogel composites is essential for various applications. The transport of ions through a droplet-hydrogel composite subjected to an electric field is theoretically studied as an initial step toward quantifying the effective transport properties of droplet-hydrogel composites. A three-phase electrokinetic model is used to derive the microscale characteristics of the polyelectrolyte hydrogel, and the droplet is considered an incompressible Newtonian fluid. The droplet-hydrogel interface is modeled as a surface, which encloses the interior fluid. The surface has the thickness of zero and the electrostatic potential ζ. Standard...
Investigating the effects of pH, surfactant and ionic strength on the stability of alumina/water nanofluids using DLVO theory
, Article Journal of Thermal Analysis and Calorimetry ; 2018 ; 13886150 (ISSN) ; Yoozbashizadeh, H ; Madaah Hosseini, H. R ; Sharif University of Technology
Springer Netherlands
2018
Abstract
Alumina nanofluids are one of the most useful nanofluids. In order to evaluate the colloidal behavior of nanoparticles in alumina/water nanofluid, the influence of effective factors such as pH, ionic strength and surfactants, was studied. Zeta potential, particle size and turbidity change of each nanofluid was investigated. According to the results for 0.05, 0.1 and 0.2 mass% nanofluid, point of zero charge was obtained at pH values of 9.5, 10.2 and 10.5, respectively. The highest nanofluid stability occurred at pH 4 and its lowest was at pH 10. The anionic surfactant had a greater effect on the stability in compared with cationic and nonionic surfactants. By increasing in ionic strength,...
The effect of pH and ionic strength on the transport of alumina nanofluids in water-saturated porous media: Experimental and modeling study
, Article Journal of Thermal Analysis and Calorimetry ; Volume 137, Issue 4 , 2019 , Pages 1169-1179 ; 13886150 (ISSN) ; Yoozbashizadeh, H ; Madaah Hosseini, H. R ; Sharif University of Technology
Springer Netherlands
2019
Abstract
Alumina nanofluids are one of the most useful nanofluids, especially for increasing the thermal conductivity. Due to importance of porous media in the improvement of heat transfer, this study investigates the transport and retention of gamma alumina/water nanofluid in the water-saturated porous media. For this purpose, alumina nanofluids were introduced to the porous media consisting of water-saturated glass beads possessing various pH values (4, 7 and 10) and different ionic strengths (0.001 M of KCl, CaCl2, AlCl3, K2SO4, CaSO4, Al2(SO4)3, K2CO3 and CaCO3). Then the break through curve of each experiment was drawn and modeled by combining classical filtration theory with...
Investigating the effects of pH, surfactant and ionic strength on the stability of alumina/water nanofluids using DLVO theory
, Article Journal of Thermal Analysis and Calorimetry ; Volume 135, Issue 2 , 2019 , Pages 1185-1196 ; 13886150 (ISSN) ; Yoozbashizadeh, H ; Madaah Hosseini, H. R ; Sharif University of Technology
Springer Netherlands
2019
Abstract
Alumina nanofluids are one of the most useful nanofluids. In order to evaluate the colloidal behavior of nanoparticles in alumina/water nanofluid, the influence of effective factors such as pH, ionic strength and surfactants, was studied. Zeta potential, particle size and turbidity change of each nanofluid was investigated. According to the results for 0.05, 0.1 and 0.2 mass% nanofluid, point of zero charge was obtained at pH values of 9.5, 10.2 and 10.5, respectively. The highest nanofluid stability occurred at pH 4 and its lowest was at pH 10. The anionic surfactant had a greater effect on the stability in compared with cationic and nonionic surfactants. By increasing in ionic strength,...
Multi-stimuli-responsive hydrogels and their medical applications
, Article New Journal of Chemistry ; Volume 45, Issue 35 , 2021 , Pages 15705-15717 ; 11440546 (ISSN) ; Heydarpour, R ; Tehrani, Z. M ; Sharif University of Technology
Royal Society of Chemistry
2021
Abstract
The functionality of multi-stimuli-responsive hydrogels in physiological states is the reason for the increased attention of hydrogels nowadays. Multi-stimuli-responsive hydrogels exhibit tunable changes in swelling or mechanical properties in response to predetermined combinations of stimuli such as pH, temperature, ionic strength, electric field, magnetic field, light, chemical triggers, enzyme concentration, redox species, reactive oxygen species (ROS), and glucose levels. This review summarizes the recent advances in multi-stimuli-responsive hydrogels used in medical approaches. The first part of the review highlights the medical applications of polymer-based and supramolecular hydrogels...
Partially hydrolyzed crosslinked alginate-graff-polymethacrylamide as a novel biopolymer-based superabsorbent hydrogel having pH-responsive properties
, Article Macromolecular Research ; Volume 13, Issue 1 , 2005 , Pages 45-53 ; 15985032 (ISSN) ; Amini Fazl, M. S ; Hosseinzadeh, H ; Sharif University of Technology
Polymer Society of Korea
2005
Abstract
In this study, a series of highly swelling hydrogels based on sodium alginate (NaAlg) and polymethacrylamide (PMAM) was prepared through free radical polymerization. The graft copolymerization reaction was performed in a homogeneous medium and in the presence of ammonium persulfate (APS) as an initiator and N,N'-methylenebisacrylamide (MBA) as a crosslinker. The crosslinked graft copolymer, alginate-graft-polymethacrylamide (Alg-g-PMAM), was then partially hydrolyzed by NaOH solution to yield a hydrogel, hydrolyzed alginate-graft-polymethacrylamide (H-Alg-g-PMAM). During alkaline hydrolysis, the carboxamide groups of Alg-g-PMAM were converted into hydrophilic carboxylate anions. Either the...
Smartwater flooding in a carbonate asphaltenic fractured oil reservoir - Comprehensive fluidfluid-rock mechanistic study
, Article 19th European Symposium on Improved Oil Recovery: Sustainable IOR in a Low Oil Price World, IOR NORWAY 2017, 24 April 2017 through 27 April 2017 ; 2017 ; 9789462822092 (ISBN) ; Afzali, S ; Ahmadi, Z ; Mokhtari, R ; Ayatollahi, S ; Sharifi, M ; Kazemi, A ; Nasiri, M ; Fathollahi, S ; Sharif University of Technology
European Association of Geoscientists and Engineers, EAGE
2017
Abstract
Waterflooding has been regarded as an efficient method for pressure maintenance of oil reservoirs. x Improved techniques such as Smart Water flooding as a new EOR/IOR process has gained more momentum based on the recent research activities in this field and the reduction of oil price. Despite many efforts on achieving the governing mechanisms of Smart Water flooding in many individual fields, most of data are sparse and more possible mechanisms which explains all the interactions yet to be introduced. This experimental study used a systematic laboratory framework which is based on seawater treatments at fixed ionic strength to eliminate the ionic strength effects, NaCl considered as the...
Ultrafast and simultaneous removal of anionic and cationic dyes by nanodiamond/UiO-66 hybrid nanocomposite
, Article Chemosphere ; Volume 247 , May , 2020 ; Neshastehgar, M ; Shojaei, A ; Ghashghaeinejad, H ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this research, UiO-66 and its composite nanoparticles with thermally oxidized nanodiamond (OND) were synthesized via a simple solvothermal method and utilized as solid adsorbent for the removal of anionic methyl red (MR) dye and cationic malachite green (MG) dye from contaminated water. The synthesized adsorbents were analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), N2 adsorption–desorption, and zeta potential analyzer. The influences of various factors such as initial concentrations of the dyes, adsorption process time, solution pH, solution temperature and ionic...
Core-shell electrospun polybutylene terephthalate/polypyrrole hollow nanofibers for micro-solid phase extraction
, Article Journal of Chromatography A ; Volume 1434 , 2016 , Pages 19-28 ; 00219673 (ISSN) ; Rezvani, O ; Banihashemi, S ; Sharif University of Technology
Elsevier B.V
2016
Abstract
In the present work, a new micro-solid phase extraction (μ-SPE) sorbent as an extracting medium based on core-shell nanofibers was synthesized by electrospinning. The core-shell nanofibers of polyvinylpyrrolidone-Polybutylene terephthalate/polypyrrole (PVP-PBT/PPy) were electrospun and subsequently, modified hollow nanofibers were prepared by removing the central PVP moiety. Moreover, conventional PBT/PPy was also prepared for the comparison purposes. The homogeneity and the porous surface structure of the core-shell nanofibers were confirmed by scanning electron microscopy (SEM). The applicability of the fabricated nanofibers-coating was examined by immersed μ-SPE of some selected triazine...
Silica aerogel coated on metallic wire by phase separation of polystyrene for in–tube solid phase microextraction
, Article Journal of Chromatography A ; Volume 1500 , 2017 , Pages 69-75 ; 00219673 (ISSN) ; Bagheri, H ; Sharif University of Technology
Elsevier B.V
2017
Abstract
In this research, an attempt was made toward synthesizing a sol–gel–based silica aerogel and its subsequent coating on a copper wire by phase separation of polystyrene. Adaption of this new approach enabled us to coat the metallic wire with powder materials. The use of this method for coating, led to the formation of a porous and thick structure of silica aerogel. The coated wire was placed in a needle and used as the sorbent for in–tube solid phase microextraction of chlorobenzenes (CBs). The superhydrophobicity of sorbent on extraction efficiency was investigated by using different ratios of tetraethylorthosilicate/methyltrimethoxysilane. The surface coated with the prepared silica aerogel...
Mechanistic study of the effects of dynamic fluid/fluid and fluid/rock interactions during immiscible displacement of oil in porous media by low salinity water: Direct numerical simulation
, Article Journal of Molecular Liquids ; 2020 ; Fatemi, M ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Low salinity waterflooding (LSWF) is a process in which by lowering the ionic strength and/or manipulation of the composition of the injection water, the long term equilibrium in oil/brine/rock system is disturbed to reach a new state of equilibrium through which the oil production will be enhanced due to fluid/fluid and/or rock/fluid interactions. In spite of recent advances in the simulation of the LSWF at core scale and beyond, there are very few works that have modelled and simulated this process at the pore scale specially using direct numerical simulation (DNS). As a result the effects of wettability alteration and/or Interfacial Tension (IFT) change on the distribution of the phases...
Effects of salinity, ion type, and aging time on the crude oil-brine interfacial properties under gravity condition
, Article Journal of Petroleum Science and Engineering ; Volume 195 , December , 2020 ; Akhlaghi Amiri, H. A ; Ayatollahi, S ; Sharif University of Technology
Elsevier B.V
2020
Abstract
In this study, the impacts of salinity, ion type, and aging process were investigated on coalescence and spreading of crude oil interfaces (including an oil droplet and an oil film) under gravity, through drop rest time measurement techniques, aided by an image analysis system. Three different salt solutions of NaCl, Na2SO4, and MgCl2 were studied at different ionic strengths, ranged from 1% to 150% of Persian Gulf seawater ionic strength. According to the results, aging the oil droplet in the brine increased the interfacial rigidity. Addition of a gas phase - by thinning the surface oil film - almost doubled both rest time and spreading time values. In the aged mode, the presence of salt in...
The impact of the electrical behavior of oil-brine-rock interfaces on the ionic transport rate in a thin film, hydrodynamic pressure, and low salinity waterflooding effect
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 620 , 2021 ; 09277757 (ISSN) ; Mahani, H ; Niasar, V ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Wettability alteration is the principal low-salinity-effect (LSE) in many oil-brine-rock (OBR) systems. Our recent experimental results have demonstrated that wettability alteration by low salinity is slow. It is expected that the electrical behavior of oil/brine and rock/brine interfaces and the water film geometry control both the transient hydrodynamic pressure, and the time-scale of ionic transport in the film, thus the kinetics and degree of wettability alteration. In this paper, the electro-diffusion process induced by the imposed ionic strength gradient is simulated by solving Poisson-Nernst-Planck equations in a water film bound between two charged surfaces, using a finite...
Mechanistic study of the effects of dynamic fluid/fluid and fluid/rock interactions during immiscible displacement of oil in porous media by low salinity water: Direct numerical simulation
, Article Journal of Molecular Liquids ; Volume 322 , 2021 ; 01677322 (ISSN) ; Fatemi, M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Low salinity waterflooding (LSWF) is a process in which by lowering the ionic strength and/or manipulation of the composition of the injection water, the long term equilibrium in oil/brine/rock system is disturbed to reach a new state of equilibrium through which the oil production will be enhanced due to fluid/fluid and/or rock/fluid interactions. In spite of recent advances in the simulation of the LSWF at core scale and beyond, there are very few works that have modelled and simulated this process at the pore scale specially using direct numerical simulation (DNS). As a result the effects of wettability alteration and/or Interfacial Tension (IFT) change on the distribution of the phases...