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    Synthesis of "(aminomethyl)phosphonic acid-functionalized graphene oxide", and comparison of its adsorption properties for thorium(IV) ion, with plain graphene oxide

    , Article Radiochimica Acta ; 2021 ; 00338230 (ISSN) Doram, A ; Outokesh, M ; Ahmadi, S.J ; Zahakifar, F ; Sharif University of Technology
    De Gruyter Open Ltd  2021
    Abstract
    The current study presents a simple and scalable method for the synthesis of (aminomethyl)phosphonic acid-functionalized graphene oxide (AMPA-GO) adsorbent. The chemical structure of the new material was disclosed by different instrumental analyses (e.g. FTIR, Raman, XPS, AFM, TEM, XRD, CHN, and UV), and two pertinent mechanisms namely nucleophilic substitution and condensation were suggested for its formation. Adsorption experiments revealed that both AMPA-GO and plain GO have a high affinity toward Th(IV) ions, but the AMPA-GO is superior in terms of adsorption capacity, rate of adsorption, selectivity, pH effect, etc. Indeed, the AMPA-GO can uptake Th(IV) nearly instantaneously, and... 

    Preparation and evaluation of hydrogel composites based on starch-g-PNaMA/eggshell particles as dye biosorbent

    , Article Desalination and Water Treatment ; Volume 57, Issue 39 , 2016 , Pages 18144-18156 ; 19443994 (ISSN) Bakhshi, H ; Darvishi, A ; Sharif University of Technology
    Taylor and Francis Inc 
    Abstract
    In this study, eggshell (ES) particles as an available and low-cost waste material were used for preparing hydrogel composites as dye biosorbents. For this purpose, hydrogel composites were prepared through free-radical graft copolymerization of wheat starch and sodium methacrylate (NaMA) in the presence of different contents of ES particles with various size ranges. FTIR spectroscopy confirmed graft copolymerization of NaMA moieties onto starch backbone besides the combination of ES particles with the starch-g-PNaMA matrix. The gel content values were high (>99%), which showed proper graft efficiency for hydrogel composites. Incorporation of ES particles into hydrogel matrix resulted in... 

    Removal of Cu (ll) from industrial wastewater using poly (acrylamide-co-2-acrylamide-2-methyl propane sulfonic acid)/graphene oxide/sodium alginate hydrogel: Isotherm, kinetics, and optimization study

    , Article Journal of Water Process Engineering ; Volume 42 , 2021 ; 22147144 (ISSN) Pishnamazi, M ; Ghasemi, S ; Khosravi, A ; ZabihiSahebi, A ; Hasan Zadeh, A ; Borghei, S. M ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    Here, Graphene oxide/poly (acrylamide -2-acrylamide-methyl-propanesulfonic acid)/sodium alginate (GO/PA-AMPS/SA) hydrogel was synthesized through a free-radical polymerization approach. The impact of Graphene Oxide (GO) content on mechanical strength, swelling behavior, and the adsorption performance of prepared hydrogel was studied. The operating parameters, including contact time, solution pH, and initial Cu(II) content on the adsorption capacity of the hydrogel, were studied. The maximum Cu(II) adsorption capacity of 230.8 mg/g was obtained for GO/PA-AMPS/SA under a pH of 5, the contact time of 270 min, and adsorbent content of 0.5 g/L at 25 °C. The high value of adsorption capacity after... 

    Experimental Investigation of Heavy Oil Recovery by Natural Surfactant Injection in Heterogeneous Systems Using Micromodel Apparatus

    , M.Sc. Thesis Sharif University of Technology Aabloo, Milad (Author) ; Rashtchian, Davood (Supervisor) ; Ghazanfari, Mohammad Hossein (Co-Advisor)
    Abstract
    Nowadays, due to limitation of production from conventional oil reservoirs, enhanced recovery from heavy oil reservoirs is of great concern. However, production from these energy resources is not a simple task and production using common technologies is not easily exploitable. Heterogeneous structure and also high surface tension between injected fluid and reservoir oil are of the main challenges during water flooding processes in heavy oil reservoirs. The high surface tension force causes a large part of the oil remains in the reservoir after the water flooding operation. One method for overcoming this problem is the use of surfactants that reduces capillary forces and consequently... 

    Synthesis of Graphene by New Methods, and its Application for Adsorption of Cobalt

    , M.Sc. Thesis Sharif University of Technology Faham Mofrad, Ali (Author) ; Outokesh, Mohammad (Supervisor) ; Shafiekhani, Azizollah (Supervisor)
    Abstract
    In this study graphene and graphene adsorbent for the Co2+ ion were created from sodium phenoxide and calcium phenoxide, respectively, using the chemical vapor deposition method, and their chemical, physical, and morphological properties were investigated using FT-IR, UV, XRD, Raman, TEM, FE-SEM, and XPS. The results suggest that the optimum reaction condition for synthesizing mono-layer and multi-layer graphene is the 750 °C temperature for 30 min. The Co2+ adsorbing properties of the synthesized graphene adsorbent from calcium phenoxide was investigated. The investigation of solvation properties suggests insolubility above 650 °C and the kinetic data suggest the rapidness of the Co2+... 

    Kinetics and Mechanism Study of Chemical Pollutant Adsorption Using Organic Ligands Modified Nano-adsorbents

    , M.Sc. Thesis Sharif University of Technology Abdollahi Zad, Ghazal (Author) ; Golami, Mohammad Reza (Supervisor)
    Abstract
    Among various methods for purifying water from dyes, adsorption takes advantage of simplicity, high efficiency, no secondary-pollution, and inexpensiveness. In this project Halloysite nanoparticles were applied to prepare a series of modified polyAcrylamide- quince seed gum hydrogels (QS/PAAm/Haln). The obtained hydrogels demonstrated improved efficiency as adsorbent in removing methylene blue (MB) from aqueous media. The structure of the prepared hydrogel nanocomposites were identified by X-ray diffraction, Brunauer-Emmett-Teller surface area analysis, Fourier-transform infrared spectroscopy, scanning electron microscope and energy-dispersive X-ray spectroscopy. Kinetics, thermodynamic,... 

    Asphaltene deposition in different depositing environments: Part 1. model oil

    , Article Energy and Fuels ; Vol. 28, Issue. 3 , 2014 , pp. 1617-1628 ; ISSN: 08870624 Tavakkoli, M ; Panuganti, S. R ; Vargas, F. M ; Taghikhani, V ; Pishvaie, M. R ; Chapman, W. G ; Sharif University of Technology
    Abstract
    Among the asphaltene flow assurance issues, the most major concern because of asphaltene is its potential to deposit in reservoir, well tubing, flow lines, separators, and other systems along production lines causing significant production losses. Hence, the focus of this study is to understand the depositional tendency of asphaltene using quartz crystal microbalance with dissipation (QCM-D) measurements. The results are presented in two consecutive papers, with this paper (part 1) dealing with model oil systems. The depositing environment is varied by changing the system temperature, asphaltene polydispersity, solvent (asphaltene stability), depositing surface, and flow rate. This paper... 

    Dynamics of Rear Stagnant Cap formation at the surface of spherical bubbles rising in surfactant solutions at large Reynolds numbers under conditions of small Marangoni number and slow sorption kinetics

    , Article Advances in Colloid and Interface Science ; Volume 222 , 2015 , Pages 260-274 ; 00018686 (ISSN) Dukhin, S. S ; Kovalchuk, V. I ; Gochev, G. G ; Lotfi, M ; Krzan, M ; Malysa, K ; Miller, R ; Sharif University of Technology
    Elsevier  2015
    Abstract
    On the surface of bubbles rising in a surfactant solution the adsorption process proceeds and leads to the formation of a so called Rear Stagnant Cap (RSC). The larger this RSC is the stronger is the retardation of the rising velocity. The theory of a steady RSC and steady retarded rising velocity, which sets in after a transient stage, has been generally accepted. However, a non-steady process of bubble rising starting from the initial zero velocity represents an important portion of the trajectory of rising, characterized by a local velocity profile (LVP). As there is no theory of RSC growth for large Reynolds numbers Re « 1 so far, the interpretation of LVPs measured in this regime was... 

    Kinetics and adsorptive study of organic dye removal using water-stable nanoscale metal organic frameworks

    , Article Materials Chemistry and Physics ; Volume 233 , 2019 , Pages 267-275 ; 02540584 (ISSN) Hasanzadeh, M ; Simchi, A ; Shahriyari Far, H ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    Kinetics and isotherms of adsorption behavior of nanoscale Zr-based metal-organic framework for the removal of three organic dyes including acidic, direct and basic ones from aqueous solutions were studied by sorption models. Nanocube-shaped UiO-66 particles with an average edge length of 215 nm, specific surface area of 1215 m2/g, total pore volume of 0.58 cm3/g, and average pore diameter of 1.8 nm were prepared by solvothermal methods. Analyzing of the equilibrium isotherms indicates that direct dye removal is best fitted with the Langmuir isotherm. Study of the adsorption kinetics also determines that direct dye adsorption follows pseudo-first-order model (R2=0.99). The kinetics of basic... 

    Modified Zeolitic Nanostructures: Synthesis, Characterization and the Investigation of Their Catalytic-Sorption-Antibacterial Applications

    , Ph.D. Dissertation Sharif University of Technology Padervand, Mohsen (Author) ; Gholami, Mohammad Reza (Supervisor) ; Gobal, Fereydoun (Co-Advisor)
    Abstract
    Modified zeolitic nanostructures were prepared by sol-gel, hydrothermal and coprecipitation methods. At first step, natural zeolite was used as a support for preparing the Ag/AgBr/TiO2 photocatalysts. Their photocatalytic properties were studied by degradation of pollutants and microorganism inactivation at the presence of different illumination source. These processes were mechanistically investigated and the results were explained. At second step, mordenite anocrystals, which synthesized by hydrothermal method, were used as an effective support to prepare the AgX/TiO2/MOR photocatalysts. Photocatalytic degradation of an azo dye performed over these nanocomposites and a mechanism suggested... 

    Investigation of Asphaltene Electro-deposition Under Dynamic Flow Conditions

    , M.Sc. Thesis Sharif University of Technology Azari, Vahid (Author) ; Taghikhani, Vahid (Supervisor) ; Ayatollahi, Shahabodin (Supervisor)
    Abstract
    Asphaltene, known as the heaviest and the most polar component of the crude oil, can precipitate because of the changes in the fluid condition such as pressure, temperature and composition. Asphaltene deposition causes major problems during oil production, in the form of fluid viscosity changes, wellbore damage and fouling in pipelines. The remediation of these problems is very expensive and needs to halt down the crude oil production. The use of electric field has been proposed recently as clean and cheap technique that could also be applied during the production period. In this work, the effect of electric potential on asphaltene precipitation in both static and dynamic modes has been... 

    Spotlight on kinetic and equilibrium adsorption of a new surfactant onto sandstone minerals: A comparative study

    , Article Journal of the Taiwan Institute of Chemical Engineers ; Volume 50 , May , 2015 , Pages 12-23 ; ISSN: 18761070 Arabloo, M ; Ghazanfari, M. H ; Rashtchian, D ; Sharif University of Technology
    Abstract
    This paper presents a state of the art review of adsorption models for a new plant-based surfactant adsorption onto sandstone minerals. The adsorption data at both kinetic and equilibrium modes were obtained from batch experiments. Four adsorption kinetic models, five two-parameter, and six three-parameter equilibrium models were used for interpretation of the obtained data. Among the two and three-parameter isotherm models applied, the Jovanovic and the Khan isotherms showed the best fit, respectively. And the pseudo-second order model presented a better fit than other kinetic models. Finally, a computer-based modeling approach was developed and used for predicting the kinetics of... 

    Spotlight on kinetic and equilibrium adsorption of a new surfactant onto sandstone minerals: A comparative study

    , Article Journal of the Taiwan Institute of Chemical Engineers ; Volume 50 , May , 2015 , Pages 12-23 ; 18761070 (ISSN) Arabloo, M ; Ghazanfari, M. H ; Rashtchian, D ; Sharif University of Technology
    Taiwan Institute of Chemical Engineers  2015
    Abstract
    This paper presents a state of the art review of adsorption models for a new plant-based surfactant adsorption onto sandstone minerals. The adsorption data at both kinetic and equilibrium modes were obtained from batch experiments. Four adsorption kinetic models, five two-parameter, and six three-parameter equilibrium models were used for interpretation of the obtained data. Among the two and three-parameter isotherm models applied, the Jovanovic and the Khan isotherms showed the best fit, respectively. And the pseudo-second order model presented a better fit than other kinetic models. Finally, a computer-based modeling approach was developed and used for predicting the kinetics of... 

    Kinetics of oxygen adsorption on ZnS nanoparticles synthesized by precipitation process

    , Article Materials Science- Poland ; Volume 34, Issue 2 , 2016 , Pages 260-265 ; 20831331 (ISSN) Ahmadi, R ; Sadrnezhad, S. K ; Namivandi Zangeneh, R ; Oghabian, M. A ; Sharif University of Technology
    Walter de Gruyter GmbH 
    Abstract
    ZnS nanoparticles were synthesized through a one-step precipitation process. Effect of time and temperature on the formation reaction was investigated. The synthesized samples were characterized by X-ray diffraction (XRD), ultraviolet (UV) visible absorption and photoluminescence (PL) spectrophotometry. Based on XRD and UV-Vis data, the particles produced at 70 °C had a mean particle size of about 5 nm. Increasing time and temperature of the synthesis reaction resulted in photoluminescence intensification. PL spectroscopy helped understanding the adsorption kinetics of oxygen on ZnS nanoparticles during the precipitation synthesis process. Fabrication of ZnS structures with appropriate... 

    Spinel H4Ti5O12 nanotubes for Li recovery from aqueous solutions: Thermodynamics and kinetics study

    , Article Journal of Environmental Chemical Engineering ; Volume 9, Issue 1 , 2021 ; 22133437 (ISSN) Shoghi, A ; Ghasemi, S ; Askari, M ; Khosravi, A ; Hasan Zadeh, A ; Alamolhoda, A. A ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    In this study, H4Ti5O12 nanotubes have been prepared as Li+ adsorbent by acid treatment of Li4Ti5O12 nanotubes. Li4Ti5O12 nanotubes were synthesized via a hydrothermal method in which TiO2(B) nanNotubes were used as a precursor. The prepared Li-ion sieve showed a significant high ion-exchange capacity (160.6 mgg−1) for lithium ions due to its large specific surface area of 115.4 m2 g-1 compared to the other related studies. The kinetics and isotherm investigation revealed that the pseudo-second-order equation well described the adsorption kinetics, and the Langmuir model well fitted the isotherm data. Furthermore, the low value of adsorption energy obtained from the Dubinin-Radushkevitch... 

    Fe3O4@PAA@UiO-66-NH2 magnetic nanocomposite for selective adsorption of Quercetin

    , Article Chemosphere ; Volume 275 , 2021 ; 00456535 (ISSN) Ahmadijokani, F ; Tajahmadi, S ; Haris, M. H ; Bahi, A ; Rezakazemi, M ; Molavi, H ; Ko, F ; Arjmand, M ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    In the present study, a magnetic core-shell metal-organic framework (Fe3O4@PAA@UiO-66-NH2) nanocomposite was synthesized by a facile step-by-step self-assembly technique and used for selective adsorption of the anti-cancer Quercetin (QCT) drug. The synthesized nanocomposite was well characterized using FTIR, XRD, BET, FESEM, and TEM techniques. The adsorption kinetics and isotherms of the magnetic nanocomposites for QCT were investigated in detail at different initial concentrations and temperatures. It was found that the experimental adsorption kinetic and isotherm data were precisely explained by the pseudo-second-order kinetic and Langmuir isotherm models. Moreover, the selective... 

    Bubble in flow field: A new experimental protocol for investigating dynamic adsorption layers by using capillary pressure tensiometry

    , Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Vol. 460, issue , 2014 , p. 369-376 Lotfi, M ; Bastani, D ; Ulaganathan, V ; Miller, R ; Javadi, A ; Sharif University of Technology
    Abstract
    For many years the model of a dynamic adsorption layer (DAL) is well established as explanation for the behavior of rising bubbles in surfactant solutions. This model explains the velocity profile and the evolution of the shape of a rising bubble based on the hypothesis of the balance between the drag force and the structure of the adsorbed layer governed by Marangoni convection. However, direct measurements of interfacial properties of the bubble during rising are a real challenge. Here we present a new experimental protocol called "bubble in flow field" suitable for direct measurements of dynamic interfacial properties of a bubble surface using the capillary pressure tensiometry under... 

    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
    Abstract
    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... 

    Synthesis and application of diethanolamine-functionalized polystyrene as a new sorbent for the removal of p-toluenesulfonic acid from aqueous solution

    , Article Journal of Industrial and Engineering Chemistry ; Volume 30 , October , 2015 , Pages 281-288 ; 1226086X (ISSN) Davarpanah, M ; Ahmadpour, A ; Rohani Bastami, T ; Dabir, H ; Sharif University of Technology
    Korean Society of Industrial Engineering Chemistry  2015
    Abstract
    Polystyrene resin was functionalized by diethanolamine for the efficient removal of p-toluenesulfonic acid (p-TSA) from aqueous solution. Functionalized adsorbent (DEA-PS) was characterized by elemental analysis, Fourier transform infrared spectroscopy, point of zero charge measurement and field-emission scanning electron microscopy. According to the results, maximum removal of p-TSA was observed at the pH range of 2.5-5. The adsorption kinetics of p-TSA onto DEA-PS was represented by pseudo-first-order model and the equilibrium data followed Langmuir model well. The adsorption process was endothermic and spontaneous, along with the positive change of entropy. The regeneration of DEA-PS was... 

    Cooperation within von Willebrand factors enhances adsorption mechanism

    , Article Journal of the Royal Society Interface ; Volume 12, Issue 109 , 2015 ; 17425689 (ISSN) Heidari, M ; Mehrbod, M ; Ejtehadi, M. R ; Mofrad, M. R ; Sharif University of Technology
    Royal Society of London  2015
    Abstract
    von Willebrand factor (VWF) is a naturally collapsed protein that participates in primary haemostasis and coagulation events. The clotting process is triggered by the adsorption and conformational changes of the plasma VWFs localized to the collagen fibres found near the site of injury. We develop coarse-grained models to simulate the adsorption dynamics of VWF flowing near the adhesive collagen fibres at different shear rates and investigate the effect of factors such as interaction and cooperativity of VWFs on the success of adsorption events. The adsorption probability of a flowing VWF confined to the receptor field is enhanced when it encounters an adhered VWF in proximity to the...