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    Adsorption of xylene isomers on Na-BETA zeolite: Equilibrium in batch adsorber

    , Article Microporous and Mesoporous Materials ; Volume 172 , 2013 , Pages 136-140 ; 13871811 (ISSN) Molaei Dehkordi, A ; Khademi, M ; Sharif University of Technology
    2013
    Abstract
    In this article, adsorption of p-xylene, m-xylene, o-xylene, and ethylbenzene on Na-BETA type zeolite in liquid phase at 15, 25, and 35 °C has been studied and the single adsorption isotherms have been obtained and reported. The Langmuir isotherm model was used to describe the experimental adsorption isotherm data. It was found that p-xylene is more strongly adsorbed component followed by ethylbenzene, m-xylene and o-xylene. This means that this adsorbent is selective for p-xylene. Using Langmuir isotherm model, the saturation adsorption capacities of the adsorbent were obtained as follows 143 mg/g for p-xylene, 105 mg/g for ethylbenzene, 83 mg/g for m-xylene, and 68 mg/g for o-xylene at 25... 

    Photocatalytic degradation of dibenzothiophene using La/PEG-modified TiO2 under visible light irradiation

    , Article Research on Chemical Intermediates ; Jan , 2014 , pp. 1-17 Moradi, S ; Vossoughi, M ; Feilizadeh, M ; Zakeri, S. M. E ; Mohammadi, M. M ; Rashtchian, D ; Yoosefi Booshehri, A ; Sharif University of Technology
    Abstract
    While the photocatalytic degradation of various organic compounds under UV light irradiation has been widely investigated, visible-light-induced photocatalytic degradation of low levels of pollutants such as dibenzothiophene (DBT) is occasionally reported. In the present work, lanthanide/polyethylene glycol-modified TiO2 (La/PEG/TiO2) has been successfully synthesized by a sol-gel method. The photocatalyst was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-Vis diffusive reflectance spectroscopy, and energy dispersive X-ray analysis. Moreover, the photocatalytic degradation of DBT under visible light irradiation is investigated for the... 

    Equilibrium isotherms for CO, CO2, CH4 and C2H4 on the 5A molecular sieve by a simple volumetric apparatus

    , Article Separation and Purification Technology ; Volume 28, Issue 1 , 2002 , Pages 53-60 ; 13835866 (ISSN) Pakseresht, S ; Kazemeini, M ; Akbarnejad, M. M ; Sharif University of Technology
    2002
    Abstract
    Adsorption equilibrium data for CO, CO2, CH4 and C2H4 on 5A molecular sieve were obtained at (303, 373 and 573) K and at partial pressures up to 1000 kPa. An accurate and simple volumetric apparatus was used to measure gas sorption. The Langmuir and Sips equations were used to correlate the experimental data. In spite of the relative simplicity of both isotherms, the correlation between experimental and theoretical data is good. The Sips equation with three parameters has expected a better fit than the Langmuir isotherm with two parameters. Based upon the Langmuir equation the enthalpy of adsorption and pre-exponential factor in the van't Hoff correlation were derived for all four gases. ©... 

    Pt–NiO–Al2O3/G derived from graphene-supported layered double hydroxide as efficient catalyst for p-nitrophenol reduction

    , Article Research on Chemical Intermediates ; Volume 43, Issue 10 , 2017 , Pages 5829-5839 ; 09226168 (ISSN) Akbarzadeh, E ; Gholami, M. R ; Sharif University of Technology
    Abstract
    The present work reports the synthesis of a Pt-modified NiO–Al2O3 nanocomposite derived from graphene-supported layered double hydroxide (Pt–NiO/G) and demonstrates its catalytic activity. The resulting Pt–NiO/G nanocomposite was characterized by FT-IR, XRD, FE-SEM, TEM and XPS techniques and used for catalytic reduction of p-nitrophenol (P-NP) to p-aminophenol (P-AP). The influence of graphene on catalytic activity was comparatively considered by preparation of Pt–NiO nanoparticles derived from layered double hydroxide. The superior catalytic performance of Pt–NiO/G was ascribed to the synergistic effect between Pt and NiO. Furthermore, reduction of P-NP was considered to follow a... 

    Photocatalytic degradation of dibenzothiophene using La/PEG-modified TiO2 under visible light irradiation

    , Article Research on Chemical Intermediates ; Volume 41, Issue 7 , July , 2015 , Pages 4151-4167 ; 09226168 (ISSN) Moradi, S ; Vossoughi, M ; Feilizadeh, M ; Zakeri, S. M. E ; Mohammadi, M. M ; Rashtchian, D ; Yoosefi Booshehri, A ; Sharif University of Technology
    Kluwer Academic Publishers  2015
    Abstract
    While the photocatalytic degradation of various organic compounds under UV light irradiation has been widely investigated, visible-light-induced photocatalytic degradation of low levels of pollutants such as dibenzothiophene (DBT) is occasionally reported. In the present work, lanthanide/polyethylene glycol-modified TiO2 (La/PEG/TiO2) has been successfully synthesized by a sol-gel method. The photocatalyst was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-Vis diffusive reflectance spectroscopy, and energy dispersive X-ray analysis. Moreover, the photocatalytic degradation of DBT under visible light irradiation is... 

    Biosorption of Zinc Ions Using Biomasses Produced From Four Different Types of Microbes Under Batch and Continuous Conditions

    , M.Sc. Thesis Sharif University of Technology Hosseini, Soheil (Author) ; Roostaazad, Reza (Supervisor) ; Razavi, Jalil (Supervisor)
    Abstract
    Biosorption capacity of zinc (II) by biomasses produced from four species of microorganism including two kinds of bacteria (Pseudomonas putida and Streptomyces rimosus) and two kinds of fungi ( Aspergillus niger and Phanerochate chrysosporium) in batch case were investigated and compared. In all cases dried original bio mass and dried pretreated bio mass with NaOH were used. In all cases biosorption capacity of pretreated biomasses were much higher than non-treated biuomasses to the ratio of 3.8 – 1.4 times. Freundlich and Langmuir equilibrium isotherms were used to match with experimental results of this research. Except S.rimosus, all others were completely matched with Langmuir... 

    Studies on the recovery of uranium from nuclear industrial effluent using nanoporous silica adsorbent

    , Article International Journal of Environmental Science and Technology ; Volume 9, Issue 4 , October , 2012 , Pages 629-636 ; 17351472 (ISSN) Sepehrian, H ; Samadfam, M ; Asadi, Z ; Sharif University of Technology
    Springer  2012
    Abstract
    In this paper, the sorption of uranium onto nanoporous silica adsorbent in the presence of nitrate, sulfate, chloride, fluoride and phosphate was studied. The effect of contact time between the nanoporous sorbent and aqueous solution, pH and initial concentration of uranium was also investigated. Uranium sorption onto nanoporous silica adsorbent is a very fast process as sorption rate increases with pH increment. Optimum pH for uranium sorption was 4-8. Experimental sorption isotherm is successfully described by Langmuir and Freundlich models. The results obtained by batch experiments showed that the presence of high concentration of nitrate, sulfate, chloride and phosphate anions alone had... 

    Thermodynamic evaluation of adsorption of zinc complex and ZnO nano-layer prepared by tscd method based on langmuir adsorption model

    , Article International Journal of Engineering, Transactions B: Applications ; Volume 22, Issue 2 , 2009 , Pages 179-184 ; 1728-144X (ISSN) Vaezi, M. R ; Sadrnezhaad, S. K ; Sharif University of Technology
    Materials and Energy Research Center  2009
    Abstract
    Zinc oxide thin films were deposited on soda-lime glass substrates from an aqueous zinc- containing complex by two-stage chemical deposition (TSCD) method. Longmuir adsorption model showed that the adsorption of atoms on the surface of the substrate was typically physical. The relation between the fractional coverage, θ, with the equilibrium constant of the adsorption reaction was nonlinear indicating that the adsorption was non-ideal. The percentage of porosity, 1-θ, of the thin layer was determined as a function of Zn 2+ concentration of the solution. By application of XRD technique, it was shown that pure crystalline ZnO of controllable thickness could be deposited by TSCD method on the... 

    AgPt nanoparticles supported on magnetic graphene oxide nanosheets for catalytic reduction of 4-nitrophenol: studies of kinetics and mechanism

    , Article Applied Organometallic Chemistry ; Volume 31, Issue 11 , 2017 ; 02682605 (ISSN) Kohantorabi, M ; Gholami, M. R ; Sharif University of Technology
    Abstract
    AgxPt100−x (x = 0, 25, 50, 75 and 100) nanoparticles were grown on the surface of magnetic graphene oxide nanosheets (Fe3O4@GO) for the first time. The as-prepared nanocomposites were characterized using various techniques such as Fourier transform infrared spectroscopy, powder X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller surface area analysis, vibrating sample magnetometry and thermogravimetric analysis. The Fe3O4@GO-AgxPt100−x catalysts were applied in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol using sodium borohydride (NaBH4). The synthesized nanocomposites... 

    , M.Sc. Thesis Sharif University of Technology Kalantari, Hamed (Author) ; Rosta Azad, Reza (Supervisor) ; Yagmaei, Soheila (Supervisor) ; Sana, Solat (Co-Advisor)
    Abstract
    In this work, biosorption of Zirconium from aqueous solution by A.niger as a biosorbent was investigated. For this goal, both of live and dried biomasses were used. The effect of factors pH, temperature, contact time, initial concentration of metal and biomass dosage were investigated on biosorption. To preparing dried biomass,the live biomass was dried at 60-80 º C for 24 hr and then this dried cell was crushed by mortar and pestle and the drying biomass was ground through a set of sieve with 100 mesh. Also, effect of the pretreatment of biomass by NaOH 0.5 M on biosorption was studied. Optimization of factors was performed by Response Surface Methodology (RSM). The experiments were... 

    An Experimental-Theoretical Study on Batch (Static) Sublimation and Derivation of a Correlation for its Heat Transfer Coefficient

    , M.Sc. Thesis Sharif University of Technology Mottafegh, Amir Reza (Author) ; Otukesh, Mohammad (Supervisor)
    Abstract
    The major features of batch sublimation were investigated in an experimental-theoretical study. An experimental setup with real-time displays, sublimated dry ice blocks of different sizes, with circular or rectangular geometries. When temperature of hotplate was changed from -30 to 200 oC, heat transfer coefficient “hsub” decreased from 126 to 70 W/m2K, while thermal flux increased, linearly. Weight and area of the block had a positive/negative effects on “hsub”, respectively. In theoretical part, at first, two “linear-gradient” and “cubic” models were developed by a combined mass-momentum-energy balance. The latter used Von Karman temperature profile, and in cases of circular and... 

    The modeling of kinetics and catalyst deactivation in propane dehydrogenation over Pt-Sn/γ-Al2O3 in presence of water as an oxygenated additive

    , Article Petroleum Science and Technology ; Vol. 32, issue. 10 , Mar , 2014 , pp. 1139-1149 ; ISSN: 10916466 Barghi, B ; Fattahi, M ; Khorasheh, F ; Sharif University of Technology
    Abstract
    A reduction in catalyst's activity with time-on-stream and the formation of side products are two of the problems associated with catalytic propane dehydrogenation (PDH). Previous studies have indicated that the presence of small amounts of oxygenated additives such as water can reduce coke formation and enhance catalyst activity. The aim of the present work was to develop an appropriate kinetic model for PDH over a commercial Pt-Sn/γ-Al 2O3 catalyst in the presence of small amounts of water. Experimental data were obtained from a previous study where catalytic PDH was carried out in a bench scale reactor system at atmospheric pressure in the temperature range of 575-620°C in the presence of... 

    Synthesis of magnetic graphene oxide-containing nanocomposite hydrogels for adsorption of crystal violet from aqueous solution

    , Article RSC Advances ; Volume 5, Issue 41 , Mar , 2015 , Pages 32263-32271 ; 20462069 (ISSN) Pourjavadi, A ; Nazari, M ; Hosseini, S. H ; Sharif University of Technology
    Royal Society of Chemistry  2015
    Abstract
    Magnetic nanocomposite hydrogels containing different amounts of graphene oxide were synthesized and characterized by FTIR, XRD, TGA, SEM, TEM, VSM and UV-vis spectroscopy. The prepared hydrogels were used as adsorbents for removal of a cationic dye, crystal violet, from water. The kinetics and isotherm of adsorption and the effect of different experimental conditions such as graphene oxide content, pH of the solution, contact time, adsorbent dosage and initial dye concentration on adsorption capacity were then investigated. Parameters related to kinetics and isotherm models were calculated and discussed. It was found that adsorption is well-described by pseudo-second-order kinetics and... 

    Experimental and theoretical study on BTEX removal from aqueous solution of diethanolamine using activated carbon adsorption

    , Article Journal of Natural Gas Science and Engineering ; Volume 22 , 2015 , Pages 618-624 ; 18755100 (ISSN) Aleghafouri, A ; Hasanzadeh, N ; Mahdyarfar, M ; SeifKordi, A ; Mahdavi, S. M ; Zoghi, A. T ; Sharif University of Technology
    Elsevier  2015
    Abstract
    Activated carbon beds are extensively used in sweetening units of natural gas refineries for the purification of contaminated amine solutions. Correlation of experimental adsorption data using an analytical isotherm equation is need to design an accurate activated carbon bed. In the present study, the adsorption of BTEX from Diethanolamine (DEA) solution by commercial and granular activated carbon (AC) were performed. The Langmuir, Freundlich and Sips isotherm models were used to describe the equilibrium data. The accuracy of the results obtained from the adsorption isotherm models was compared and the values for the regressed parameters were reported. The results show that the Freundlich... 

    Evaluation and modeling of a newly designed impinging stream photoreactor equipped with a TiO2 coated fiberglass cloth

    , Article RSC Advances ; Volume 5, Issue 12 , 2015 , Pages 9019-9027 ; 20462069 (ISSN) Jafarikojour, M ; Mohammadi, M. M ; Sohrabi, M ; Royaee, S. J ; Sharif University of Technology
    Royal Society of Chemistry  2015
    Abstract
    The photocatalytic degradation of p-nitrophenol (PNP) using TiO2 particles immobilized on a fiberglass cloth was investigated in a novel design of a photo-impinging stream reactor. A spray painted method has been used for the coating process. The structural properties of the immobilized sample were examined using X-ray diffraction and a scanning electron microscope (SEM). The photocatalytic degradation results showed the good performance of the reactor. The flow regime within the reactor was characterized and modeled by applying a liquid residence time distribution. A compartment model consisting of four continuous stirred regions was assigned to describe the flow pattern in the reactor. A... 

    A new functionalized magnetic nanocomposite of poly(methylacrylate) for the efficient removal of anionic dyes from aqueous media

    , Article RSC Advances ; Volume 6, Issue 10 , 2016 , Pages 7982-7989 ; 20462069 (ISSN) Pourjavadi, A ; Abedin Moghanaki, A ; Nasseri, S. A ; Sharif University of Technology
    Royal Society of Chemistry 
    Abstract
    A new magnetic nano-adsorbent was synthesized via the radical polymerization of methyl acrylate on modified Fe3O4 nanoparticles, followed by its functionalization by amidation of the methyl ester groups using pentaethylenehexamine, to create active adsorption sites for removing anionic dyes from aqueous media. Physicochemical properties of the adsorbent were then characterized by SEM, TEM, XRD, FTIR, TGA and CHN analysis. The prepared nanocomposite was used as adsorbent for the removal of anionic dyes, naphthol green B and chromeazurol S, from aqueous solution and assessed in view of the kinetics and isotherm adsorption, and the effect of solution pH, contact time and initial dye... 

    Nanodiamond-filled chitosan as an efficient adsorbent for anionic dye removal from aqueous solutions

    , Article Journal of Environmental Chemical Engineering ; Volume 6, Issue 2 , 2018 , Pages 3283-3294 ; 22133437 (ISSN) Raeiszadeh, M ; Hakimian, A ; Shojaei, A ; Molavi, H ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    A series of novel chitosan/nanodiamond (CTS/ND) composites containing NDs with variable surface carboxyl groups and various concentrations were prepared using solution casting method. Powdery CTS/ND composites were employed as the adsorbent of a model anionic dye (methyl orange, MO). Experimental results showed that the incorporation of NDs with high carboxylic content (ND-H) in to CTS increased substantially the maximum adsorption capacity of neat CTS from 167 mg/g to 454 mg/g. The remarkable adsorption capacity of dye on CTS/ND composites was associated to the oxygen-containing groups on the outer surface of NDs which would be beneficial to interact with the dye molecules through hydrogen... 

    Design and fabrication of a movable langmuir probe for plasma edge parameters measurement in the IR-T1 tokamak

    , Article Journal of Fusion Energy ; Volume 28, Issue 3 , 2009 , Pages 296-299 ; 01640313 (ISSN) Shariatzadeh, R ; Ghoranneviss, M ; Emami, M ; Anvari, A ; Van Oost, G ; Sharif University of Technology
    2009
    Abstract
    For the edge plasma parameters measurement, a movable Langmuir probe is fabricated and installed on the IR-T1 tokamak. The set-up consists of two sets of single Langmuir probes with tungsten tip movable in the radial direction. Edge plasma parameters including electron temperature, Ion density, floating potential and the corresponding radial changes are measured. Using two-point correlation technique clearly reveal that in the SOL region the poloidal propagation of floating potential fluctuation is in the direction of ion diamagnetic drift and in the edge it propagates in the electron diamagnetic drift direction. © 2009 Springer Science+Business Media, LLC  

    Experimental study on the influence of initial pH, ionic strength, and temperature on the selective adsorption of dyes onto nanodiamonds

    , Article Journal of Chemical and Engineering Data ; Volume 64, Issue 4 , 2019 , Pages 1508-1514 ; 00219568 (ISSN) ; https://pubs.acs.org/doi/abs/10.1021/acs.jced.8b01091 Molavi, H ; Pourghaderi, A ; Shojaei, A ; Sharif University of Technology
    American Chemical Society  2019
    Abstract
    In the current work, the performance of untreated nanodiamonds (UNDs) and thermally oxidized nanodiamonds (ONDs), as adsorbents for selective adsorption of methylene blue (MB) and methyl orange (MO) from aqueous media, was examined. The adsorption isotherm, initial pH, ionic strength, and thermodynamic study were investigated in batch experiments. The equilibrium adsorption data were analyzed by Langmuir and Freundlich isotherm models, which indicated that the isotherms were well fitted with the Langmuir model for both dyes. Thermodynamic parameters indicated that the adsorption operation was a feasible, spontaneous, and physisorption process in experimental conditions. Meanwhile, the... 

    Experimental study on the influence of initial pH, Ionic strength, and temperature on the selective adsorption of dyes onto nanodiamonds

    , Article Journal of Chemical and Engineering Data ; 2019 ; 00219568 (ISSN) Molavi, H ; Pourghaderi, A ; Shojaei, A ; Sharif University of Technology
    American Chemical Society  2019
    Abstract
    In the current work, the performance of untreated nanodiamonds (UNDs) and thermally oxidized nanodiamonds (ONDs), as adsorbents for selective adsorption of methylene blue (MB) and methyl orange (MO) from aqueous media, was examined. The adsorption isotherm, initial pH, ionic strength, and thermodynamic study were investigated in batch experiments. The equilibrium adsorption data were analyzed by Langmuir and Freundlich isotherm models, which indicated that the isotherms were well fitted with the Langmuir model for both dyes. Thermodynamic parameters indicated that the adsorption operation was a feasible, spontaneous, and physisorption process in experimental conditions. Meanwhile, the...