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    Survey and synthesis of zeolite adsorbents in Olefins and Paraffinssorption

    , M.Sc. Thesis Sharif University of Technology Taghavi Golsefidi, Abbas (Author) ; Soltanieh, Mohammad (Supervisor)
    Abstract
    Olefin/ paraffin separation is one of the most important processes in the petrochemical industries.In the last decades, adsorption and membrane processes are a new technology considered significantly for this purpose. In order to synthesizeof zeolite powder (pure silica zeolite STT and CHA), raw materials were made by two methods and their HNMR spectrum was recorded and thenzeolite powder was synthesized. X ray diffraction(XRD) and scanning electron microscopy (SEM) images were taken,showing the same results as the refference structure.To consider synthesized zeolite powdersand olefin/ paraffin interactions, surface adsorption ofthose gases was accomplished on two zeolite powders. After... 

    Thermodynamic study of Cr+3 ions removal by "MnO2 /MWCNT" nanocomposite

    , Article Oriental Journal of Chemistry ; Volume 31, Issue 3 , 2015 , Pages 1429-1436 ; 0970020X (ISSN) Mohammadkhani, S ; Gholami, M. R ; Aghaie, M ; Sharif University of Technology
    Oriental Scientific Publishing Company  2015
    Abstract
    In this research "MnO2/MWCNT" nanocomposite was prepared firstly and then it was used as an adsorbent for Cr+3 ions removal from aqueous solutions. Our results showed that the prepared nanocomposite from modified multi-wall carbon nanotube and MnO2 has a good capacity for Cr+3 removal from aqueous solution. Morphology and Crystallinity of the modified MWCNT before and after deposition on MnO2 were examined by SEM and XRD. In turn, the experimental results were examined according to the Langmuir, Freundlich and Temkin Isotherms and Freundlich isotherm represented our experimental results  

    Thermodynamic study of Cr+3 ions removal by "MnO2/MWCNT" nanocomposite

    , Article Oriental Journal of Chemistry ; Volume 32, Issue 1 , 2016 , Pages 591-599 ; 0970020X (ISSN) Mohammadkhani, S ; Gholami, M. R ; Aghaie, M ; Sharif University of Technology
    Oriental Scientific Publishing Company  2016
    Abstract
    In this research "MnO2/MWCNT" nanocomposite was prepared firstly and then it was used as an adsorbent for Cr+3 ions removal from aqueous solutions. Our results showed that the prepared nanocomposite from modified multi-wall carbon nanotube and MnO2 has a good capacity for Cr+3 removal from aqueous solution. Morphology and Crystallinity of the modified MWCNT before and after deposition on MnO2 were examined by SEM and XRD. In turn, the experimental results were examined according to the Langmuir, Freundlich and Temkin Isotherms and Freundlich isotherm represented our experimental results  

    Asymmetrical Schiff bases as inhibitors of mild steel corrosion in sulphuric acid media

    , Article Materials Chemistry and Physics ; Volume 78, Issue 3 , 2003 , Pages 800-808 ; 02540584 (ISSN) Hosseini, M ; Mertens, S. F. L ; Ghorbani, M ; Arshadi, M. R ; Sharif University of Technology
    2003
    Abstract
    Two newly synthesised Schiff bases [H2A3, N,N′-ortho-phenylene(salicylaldimine-acetylacetone imine) and H2A4, N,N′-ortho-phenylene(salicylaldimine-2-hydroxy-1-naphthaldimine)] were studied as inhibitors for the corrosion of mild steel in 0.5 mol dm-3 sulphuric acid. Results of weight loss, electrochemical impedance and Tafel polarisation measurements consistently identify both compounds as good inhibitors, with efficiencies of around 95% at a concentration of 400 ppm. The inhibition is in both cases of a mixed anodic-cathodic nature. Differences in inhibition efficiency between H2A3 and H2A4 are correlated with their chemical structures. Several adsorption isotherms are assessed, and the... 

    Experimental and Theoretical Study of the Effect of Moisture on Methane Adsorption and Desorption by Activated Carbon at 273.5 K

    , Article Journal of Natural Gas Chemistry ; Volume 16, Issue 1 , 2007 , Pages 22-30 ; 10039953 (ISSN) Farzad, S ; Taghikhani, V ; Ghotbi, C ; Aminshahidi, B ; Lay, E. N ; Sharif University of Technology
    2007
    Abstract
    Adsorption and desorption of methane by activated carbon (AC) at constant temperature and at various pressures were investigated. The effect of moisture was also studied. A volumetric method was used, up to 40 bar, at a temperature of 273.5 K. Results of a dry AC sample were compared with those obtained from a moist sample and two different ACs with different physical and surface properties were used. As expected, the results showed that the existence of moisture, trapped in the AC pores, could lead to a decrease in the amount of methane adsorbed and a decrease in the amount of methane delivered during desorption. To model the experimental results, a large variety of adsorption isotherms... 

    Interaction of hydrogen molecules with perfect, defective and scandium doped polycyclic aromatic hydrocarbon structures

    , Article Computational and Theoretical Chemistry ; Volume 1026 , 2013 , Pages 65-71 ; ISSN: 2210271X Lotfi, R ; Saboohi, Y ; Sharif University of Technology
    2013
    Abstract
    In the present work the interaction of hydrogen molecules with perfect, defective and scandium doped polycyclic aromatic hydrocarbon (PAH) has been evaluated. At first the potential barrier for the penetration of hydrogen molecules through PAH structures has been investigated and then the adsorption of hydrogen molecules over PAH structures has been studied. To model the graphene surface for barrier calculations, it is shown that coronene can successfully estimate the graphene monolayer. The barrier height is calculated for perfect and two different defective PAH structures including Stone-Wales (SW) and 585. It is found that PAH even with small defects is impermeable to hydrogen molecules.... 

    Influence of polyaniline synthesis conditions on its capability for removal and recovery of chromium from aqueous solution

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 30, Issue 3 , 2011 , Pages 97-100 ; 10219986 (ISSN) Riahi Samani, M ; Borghei, S. M ; Olad, A ; Chaichi, M. J ; Sharif University of Technology
    2011
    Abstract
    Absorptive characteristics of polyaniline synthesized in different solvents were studied. Water and mixture of water with other solvents were implemented for polyaniline synthesis. Synthesized polyanilines in powder shape is used as an adsorbent to remove toxic hexavalent chromium from aqueous solutions. Experiments were conducted in batch mode. Removal mechanism involving polyaniline is the combination of surface adsorption and reduction. The kind of solvent used at synthesizing stage can affect the capacity of produced polyanilines for removal of heavy metals including chromium. Synthesized polyaniline in water had the maximum chromium removal efficiency. The morphology study of... 

    Removal of chromium from aqueous solution using two kinds of polyaniline

    , Article Journal of Environmental Studies ; Volume 36, Issue 55 , 2010 , Pages 91-98 ; 10258620 (ISSN) Riahi Samani, M ; Borghei, S. M ; Olad, A ; Chaichi, M. J ; Sharif University of Technology
    2010

    Experimental study of hydrogen fluoride adsorption on sodium fluoride

    , Article Journal of Industrial and Engineering Chemistry ; Volume 16, Issue 1 , 2010 , Pages 147-151 ; 1226086X (ISSN) Afzal, S ; Rahimi, A ; Ehsani, M. R ; Tavakoli, H ; Sharif University of Technology
    Abstract
    In uranium conversion industry, the fluorine is used as chemical raw material gas to produce UF4 and UF6 while its purity is very important. In this study, the adsorption process of hydrogen fluoride, as an impurity in the process of fluorine production, on sodium fluoride pellets is experimentally studied in a lab-scale fixed bed adsorbent. Also, the effects of some operating parameters including inlet concentration and inlet temperature of hydrogen fluoride are precisely investigated on the adsorption process. The data of adsorption are analyzed and correlated by Langmuir, Freundlich and Temkin isotherms. The adsorption capacity is found to be 1.908 and 0.750 g HF/g NaF by the Langmuir... 

    Adsorption and oxidation study on arsenite removal from aqueous solutions by polyaniline/polyvinyl alcohol composite

    , Article Journal of Water Process Engineering ; Volume 14 , 2016 , Pages 101-107 ; 22147144 (ISSN) Roghani, M ; Nakhli, S. A. A ; Aghajani, M ; Rostami, M. H ; Borghei, S. M ; Sharif University of Technology
    Elsevier Ltd 
    Abstract
    In this study, the Polyaniline/Polyvinyl Alcohol (PANi/PVA) composite was examined for arsenite (As(III)) removal from aqueous solution. The effect of several parameters including PVA concetration (0–5 g/L), pH (1–13), adsorbent dosage (0.5–6 g/L), contact time (0–120 min), initial As(III) concentration (0.5–100 mg/L), and As(III) oxidation were evaluated on the adsorption efficiency. The results indicated that PVA has an effective role in increasing adsorptive capacity of PANi, by changing its morphology and extending its active surface sites. The adsorption process was pH dependent and As(III) removal consistently improved by increasing solution pH. Adsorption reached equilibrium within... 

    Batch equilibrium and kinetics studies of Cd (II) ion removal from aqueous solution using porous chitosan hydrogel beads

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 28, Issue 3 , 2009 , Pages 81-89 ; 10219986 (ISSN) Mohammad Beigi, S ; Babapoor, A ; Maghsoodi, V ; Mousavi, S. M ; Rajabi, N ; Sharif University of Technology
    Abstract
    In this study chitosan hydrogel beads with porosity ∼ 0.86 and diameter ∼ 2 ± 0.07 mm were prepared from 85 % deacetylated chitosan for removal of Cd2+ ions from aqueous solutions. Chitosan powder was dissolved into dilute acetic acid as solvent and formed into spherical beads using a phase inversion technique. The effect of temperature, initial concentration of Cd2+ ions, and the period of agitation were perused to achieve the best isotherm model. Freundlich model was better fitted than Langmuir model (R2 > 0.99 and R2> 0.93 respectively, at pH of 6.3, and shaker speed of 200 rpm), the constants of Langmuir and Freundlich models were calculated, which RL value and qmax (mg/g wet weight) at... 

    Selection of adsorbents for different applications and processes: A review

    , Article Petroleum and Coal ; Volume 61, Issue 5 , 2019 , Pages 932-948 ; 13377027 (ISSN) Sadighi, S ; Sheikh Alivand, M ; Faghihi, M ; Sharif University of Technology
    Slovnaft VURUP a.s  2019
    Abstract
    Adsorption is one of the most sophisticated separation processes widely used in oil, gas and petrochemical facilities, and there is no doubt in the environmental and technological significant of this technology. But, the key to design an efficient adsorption service is to accurately select a suitable adsorbent that strongly dependent to the feed composition, product specification, and operating conditions. During the last 30 years, different classes of solid adsorbent have been manufactured; but, they should be meticulously chosen accordingly. In this paper, the specification and main charac-teristics of adsorbents generally used in oil, gas and petrochemical processes including activated... 

    Removal of fluoride from wastewater by natural and modified nano clinoptilolite zeolite

    , Article Journal of Water and Environmental Nanotechnology ; Volume 5, Issue 3 , 2020 , Pages 270-282 Ghomashi, P ; Charkhi, A ; Kazemeini, M ; Yousefi, T ; Sharif University of Technology
    Iranian Environmental Mutagen Society  2020
    Abstract
    In this study adsorption of fluoride ion from high-fluorine solutions (<2000 ppm) using the natural and modified ground clinoptilolite is investigated. These low-cost adsorbents are carefully characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF), thermos-gravimetry (TGA) and differential scanning calorimeter analysis (DSC). In order to enhance the fluoride removal capacity of natural zeolite, it is milled into nano-powders and modified using hexadecyltriammoniumions (HDTMA+). The kinetic, equilibrium, and thermodynamic of fluoride adsorption are measured and described by the well-known... 

    Synthesis of magnetic bio-nanocomposites for drug release and adsorption applications

    , Article South African Journal of Chemical Engineering ; Volume 42 , 2022 , Pages 115-126 ; 10269185 (ISSN) Rezghi Rami, M ; Meskini, M ; Qarebaghi, L. M ; Salami, M ; Forouzandehdel, S ; Cheraghali, M ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    Aims: Synthesis of nanocarrier Fe3O4/silica-starch/PNVCL for drug delivery and Fe3O4/GO-starch for antibiotic removal applications Background: In the first part, the new magnetic nanocomposite including Fe3O4 nanoparticles coated with silica, anchored starch nanoparticles, and poly(N-vinylcaprolactam) and then, loaded by acetazolamide. In the second part, magnetic starch nanocomposites were synthesized and modified with graphene oxide. Methods: The drug loading, release and intrinsic cytotoxicity were measured. Also, the potential of Fe3O4/GO-starch as an adsorbent to remove cephalexin antibiotics from aqueous solutions was evaluated. Result: In the first part, the maximum drug adsorption... 

    Coordination chemistry of metal–organic frameworks: Detection, adsorption, and photodegradation of tetracycline antibiotics and beyond

    , Article Coordination Chemistry Reviews ; Volume 464 , 2022 ; 00108545 (ISSN) Ahmadijokani, F ; Molavi, H ; Tajahmadi, S ; Rezakazemi, M ; Amini, M ; Kamkar, M ; Rojas, O. J ; Arjmand, M ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    Tetracyclines (TCs) are a large family of broad-spectrum antibiotics with one of the highest aquatic persistence after release from humans and animals. Hence, TCs are known to generate antibiotic resistance along with estrogenic and other toxic effects in non-target organisms. Unfortunately, the detection and removal of TCs from aqueous matrices remain challenging. For this purpose, we review metal–organic frameworks (MOFs), which have emerged as effective alternatives, given their photocatalytic and adsorptive capabilities. MOFs exhibit large interactive surface area and tunable structure and pore size for fast mass transfer and strong host–guest interactions. Herein, these and other topics... 

    Removal of Cu 2+ , Cd 2+ and Ni 2+ ions from aqueous solution using a novel chitosan/polyvinyl alcohol adsorptive membrane

    , Article Carbohydrate Polymers ; Volume 210 , 2019 , Pages 264-273 ; 01448617 (ISSN) Sahebjamee, N ; Soltanieh, M ; Mousavi, S. M ; Heydarinasab, A ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    The chitosan/poly vinyl alcohol membrane was modified by addition of some amine group to the membrane structure utilizing polyethyleneimine (PEI) in order to increase ionic metals adsorbent properties of the membrane. The removal percentage of the modified membranes was compared with the pristine membrane and activated carbon as common adsorbents. The membranes were characterized by FTIR, SEM, swelling degree and porosity measurement. The removal percentage of the membrane containing 0.5 wt.% PEI was more than 60% higher than the activated carbon and more than 40% higher than the pristine membrane. The modified membrane showed excellent adsorption capacity of 112.13, 86.08, and 75.5 mg/g for... 

    Water adsorption in the organic phase for the D2EHPA-kerosene/water and aqueous Zn2+, Co2+, Ni2+ sulphate systems

    , Article Hydrometallurgy ; Volume 88, Issue 1-4 , 2007 , Pages 92-97 ; 0304386X (ISSN) Darvishi, D ; Haghshenas, D. F ; Etemadi, S ; Keshavarz Alamdari, E ; Sadrnezhaad, Kh ; Sharif University of Technology
    2007
    Abstract
    Water adsorption by bis-2-ethylhexyl phosphoric acid (D2EHPA) during the extraction of zinc, cobalt and nickel using a D2EHPA-kerosene/H2O mixture is investigated. Based on the experimental results, about 1 mol of water is adsorbed by 2 mol of D2EHPA (which exists in the form of a dimer), irrespective of the pH. Water adsorption decreases with presence of zinc, cobalt and nickel. The stoichiometric coefficients of D2EHPA in water adsorption reactions are determined with and without zinc, cobalt and nickel by applying the slope-analysis method. It is experimentally confirmed that 1.0, 1.8 and 1.2 mol of adsorbed water will be rejected from the organic phase when zinc, cobalt and nickel are... 

    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... 

    A new model based on multilayer kinetic adsorption mechanism for asphaltenes adsorption in porous media during dynamic condition

    , Article Fluid Phase Equilibria ; Vol. 375, issue , 2014 , Pages 236-245 ; ISSN: 03783812 Jafari Behbahani, T ; Ghotbi, C ; Taghikhani, V ; Shahrabadi, A ; Sharif University of Technology
    Abstract
    In this work, a new model based on multilayer kinetic adsorption mechanism has been proposed to account asphaltene adsorption in porous media under dynamic condition and the model was verified using experimental data obtained in this work and also with those reported in the literature. In the proposed model two steps are considered for asphaltene adsorption. The first step is taken as adsorption of asphaltenes on the surface of the porous media and the second step is taken as adsorption of asphaltenes on the asphaltenes already adsorbed on the porous media. The Crank-Nicholson method, central difference in space and trapezoidal rule in time, giving second order convergence in time was... 

    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...