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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) ; 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...
Chromogenic detection of xylene isomers and luminogenic chemosensing of o-xylene employing a new macrocyclic cobalt complex: synthesis, and X-ray crystallographic, spectroscopic and computational studies
, Article New Journal of Chemistry ; Volume 46, Issue 43 , 2022 , Pages 20745-20754 ; 11440546 (ISSN) ; Asadi Mofarrah, L ; Jamjah, A ; Sharif University of Technology
Royal Society of Chemistry
2022
Abstract
Here, we report the synthesis and characterization of a binuclear Co(ii) complex (Co2(2py)2Cl4) with two dinaphtho-diazacrown ether macrocyclic ligands, bearing two pyridine arms as a colourimetric and fluorescent sensor for detecting different xylene isomers as well as acting as a catalyst for the oxidation of o- and m-xylene under vacuum at room temperature. Chromogenic detection occurred when Co2(2py)2Cl4 was exposed to the xylene isomers, wherein the original blue colour of the complex changed to green and green-blue in the presence of o- and m-xylene, respectively. Meanwhile, no colour change was observed in the presence of the p-xylene isomer. Fluorescence spectroscopy revealed that...
Liquid-liquid equilibrium (LLE) data for ternary mixtures of {aliphatic+p-xylene+[EMpy][ESO 4]} at T=313.15K
, Article Fluid Phase Equilibria ; Volume 332 , 2012 , Pages 48-54 ; 03783812 (ISSN) ; Vossoughi, M ; Shamloo, A ; Mirkhani, S. A ; Akbari, J ; Sharif University of Technology
Elsevier
2012
Abstract
Liquid-liquid equilibrium (LLE) data for the ternary systems (heptane. +. p-xylene. +. 1-ethyl-3-methylpyridinium ethylsulfate) and (n-octane. +. p-xylene. +. 1-ethyl-3-methylpyridinium ethylsulfate) were measured at . T=. 313.15. K and atmospheric pressure. The selectivity and aromatic distribution coefficients, calculated from the equilibrium data, were used to determine if this ionic liquid can be used as a potential extracting solvent for the separation of p-xylene from heptane and n-octane. The consistency of tie-line data was ascertained by applying the Othmer-Tobias and Hand equations
Degradation of benzene, toluene, and xylene (BTX) from aqueous solution by isolated bacteria from contaminated sites
, Article Research on Chemical Intermediates ; Volume 41, Issue 1 , January , 2015 , Pages 265-275 ; 09226168 (ISSN) ; Yaghmaei, S ; Vafaei, F ; Khataee, A. R ; Hejazi, M. S ; Sharif University of Technology
Kluwer Academic Publishers
2015
Abstract
The present study was carried out to evaluate the degradation efficiency of benzene, toluene, and xylene (BTX) by isolated bacteria from various petroleum-hydrocarbons contaminated sites. Five isolated bacteria were selected for testing BTX biodegradation from liquid culture media. Each of these bacteria was able to degrade BTX but with different efficiencies. Maximum biodegradation efficiency for benzene (more than 70 %) was obtained by Gram-positive coccobacillus, Gram-positive coccus and Gram-negative bacillus bacteria, for toluene (60 %) and xylene (70 %) by Gram-positive coccobacillus and Gram-negative coccobacillus. It was found that the presence of xylene in the substrate mixture...
Spatiotemporal description of BTEX volatile organic compounds in a middle eastern megacity: tehran study of exposure prediction for environmental health research (Tehran SEPEHR)
, Article Environmental Pollution ; Volume 226 , 2017 , Pages 219-229 ; 02697491 (ISSN) ; Hosseini, V ; Schindler, C ; Hassankhany, H ; Yunesian, M ; Henderson, S. B ; Künzli, N ; Sharif University of Technology
Abstract
The spatiotemporal variability of ambient volatile organic compounds (VOCs) in Tehran, Iran, is not well understood. Here we present the design, methods, and results of the Tehran Study of Exposure Prediction for Environmental Health Research (Tehran SEPEHR) on ambient concentrations of benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene (BTEX), and total BTEX. To date, this is the largest study of its kind in a low- and middle-income country and one of the largest globally. We measured BTEX concentrations at five reference sites and 174 distributed sites identified by a cluster analytic method. Samples were taken over 25 consecutive 2-weeks at five reference sites (to be used for...
Land use regression models for Alkylbenzenes in a middle eastern megacity: Tehran study of exposure prediction for environmental health research (tehran sepehr)
, Article Environmental Science and Technology ; Volume 51, Issue 15 , 2017 , Pages 8481-8490 ; 0013936X (ISSN) ; Schindler, C ; Hosseini, V ; Yunesian, M ; Künzli, N ; Sharif University of Technology
American Chemical Society
2017
Abstract
Land use regression (LUR) has not been applied thus far to ambient alkylbenzenes in highly polluted megacities. We advanced LUR models for benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene (BTEX), and total BTEX using measurement based estimates of annual means at 179 sites in Tehran megacity, Iran. Overall, 520 predictors were evaluated, such as The Weather Research and Forecasting Model meteorology predictions, emission inventory, and several new others. The final models with R2 values ranging from 0.64 for p-xylene to 0.70 for benzene were mainly driven by traffic-related variables but the proximity to sewage treatment plants was present in all models indicating a major local...
Separation of Xylene Isomers
, M.Sc. Thesis Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor)
Abstract
Xylene isomers have similar boiling points and, therefore, their separation by conventional distillation is not practical. The industrial separation of these isomers is generally performed by adsorption or crystallization processes, which are very energy consuming. In this work, the various methods of the separation of these isomers have been reviewed and the equilibrium adsorption of these components in liquid phase using two commercial types of zeolite including Z-700 and Na-BETA as adsorbent at 15, 25, and 35 oC and an initial concentration range of up to 50 wt% as well as in single and binary solutions was investigated. It was found that Z-700 adsorbent has no selectivity for the binary...
Design and Simulation of Simulated Moving Beds
, M.Sc. Thesis Sharif University of Technology ; Farhadi, Fathollah (Supervisor)
Abstract
In this thesis design and simulation of SMB for four different mixture was done with Aspen chromatography package. Simulation for three mixtures of D-Psicose and D-Fructose, racemic mixture of Bupivacaine and Ibuprofen racemate were done with the aim of validation, based on experimental data of articles. The simulation results matched well with the experimental results in articles. The separation of p-xylene from mixed C8 aromatics and Para Diethyl benzene (as desorbent), was simulated for one of the p-xylene producing units and results were validated against the PFD. The influence of various parameters on the purity and recovery of p-xylene were investigated. The studies showed high...
Improving the Remediation Process of Asphaltene Deposits in the Well Facility of Koupal-Bangestan Oil Reservoir
, M.Sc. Thesis Sharif University of Technology ; Ayatollahi, Shahaboddin (Supervisor) ; Ghotbi, Cyrus (Supervisor)
Abstract
Crude oil production could cause the thermodynamic equilibrium of the crude oil to be disturbed in the well column which results in asphaltene precipitation and deposition. The thickness of the deposited material grows over time until it completely blocks the well column.Due to the hard and insoluble nature of deposited asphaltene, the two main chemical and mechanical methods are found to be more effective. It should be noted that the actual organic sediments in the piping are not pure and consist of three components: asphaltene, resin and paraffin. Therefore, it is very important to know the composition of the deposited material before selecting the appropriate chemical solvent.The samples...
Equilibrium modeling of xylene adsorption on molecular sieves
, Article Fluid Phase Equilibria ; Volume 298, Issue 1 , November , 2010 , Pages 54-59 ; 03783812 (ISSN) ; Baghalha, M ; Khorasheh, F ; Behvandi, A ; Sharif University of Technology
2010
Abstract
The separation of xylene isomers is an important application in separation processes that is based on their adsorption properties on different adsorbents. In this work, the Price and Danner method was employed with a neural network to investigate the adsorption behavior of binary systems of p-xylene/m-xylene, p-diethyl benzene/m-xylene, and p-diethyl benzene/p-xylene and the ternary system of p-diethyl benzene/m-xylene/p-xylene at 130 and 175°C. The Redlich-Kister, Wilson, and NRTL models were used to determine the activity coefficients in the adsorbed phase. Comparison with experimental data from the literature indicated that the proposed thermodynamic model would best determine surface...
Sensing behavior of flower-shaped MoS2 nanoflakes: Case study with methanol and xylene
, Article Beilstein Journal of Nanotechnology ; Volume 9, Issue 1 , 2018 , Pages 608-615 ; 21904286 (ISSN) ; Berahman, M ; Iraji zad, A ; Sharif University of Technology
Beilstein-Institut Zur Forderung der Chemischen Wissenschaften
2018
Abstract
Recent research interest in two-dimensional (2D) materials has led to an emerging new group of materials known as transition metal dichalcogenides (TMDs), which have significant electrical, optical, and transport properties. MoS2 is one of the well-known 2D materials in this group, which is a semiconductor with controllable band gap based on its structure. The hydrothermal process is known as one of the scalable methods to synthesize MoS2 nanostructures. In this study, the gas sensing properties of flower-shaped MoS2 nanoflakes, which were prepared from molybdenum trioxide (MoO3) by a facile hydrothermal method, have been studied. Material characterization was performed using X-ray...
Degradation of BTEX in groundwater by nano-CaO2 particles activated with L-cysteine chelated Fe(III): enhancing or inhibiting hydroxyl radical generation
, Article Water Supply ; Volume 21, Issue 8 , 2021 , Pages 4429-4441 ; 16069749 (ISSN) ; Ali, M ; Cui, C ; Lyu, S ; Sharif University of Technology
IWA Publishing
2021
Abstract
The simultaneous oxidation performance of benzene, toluene, ethylbenzene, and xylene (BTEX) by nanoscale calcium peroxide particles (nCaO2) activated with ferric ions (Fe(III)) and the mechanism of the enhancement of BTEX degradation by L-cysteine (L-cys) were investigated. The batch experimental results showed that the nCaO2/Fe(III)/L-cys process was effective in the destruction of BTEX in both ultrapure water and actual groundwater. A proper amount of L-cys could enhance BTEX degradation due to the promotion of Fe(II)/Fe(III) redox cycles by the participation of L-cys, but an excessive presence of L-cys would cause inhibition. Adding 1.0 mM L-cys to the nCaO2/Fe(III) system, the...
Analysis and interaction of exergy, environmental and economic in multi-objective optimization of BTX process based on evolutionary algorithm
, Article Energy ; Volume 59 , 2013 , Pages 147-156 ; 03605442 (ISSN) ; Farhadi, F ; Boozarjomehry, R. B ; Sharif University of Technology
2013
Abstract
In this paper sustainability analysis (exergy, environmental and economic) and multi-objective optimization for an aromatic plant are provided and interactions between decision variables are discussed. Environmental evaluation shows that the cancer human toxicity and global warming are the most important environmental concerns and the weight of EIs (environmental impacts) are mainly due to process wastes. The optimizations results demonstrate parameters like reactor temperature have a wide range in the optimizations while some variables, such as extraction unit variables have the same value. Utility EI reduction occurred in economic and exergy optimizations rather than environmental...
Probing solvent-solvent and solute-solvent interactions in surfactant binary mixtures: Solvatochromic parameters, preferential solvation, and quantum theory of atoms in molecules analysis
, Article RSC Advances ; Volume 6, Issue 22 , 2016 , Pages 18515-18524 ; 20462069 (ISSN) ; Fakhraee, M ; Salari, H ; Gholami, M. R ; Sharif University of Technology
Royal Society of Chemistry
Abstract
The behaviour of solvatochromic absorbance probes (4-nitroaniline, 4-nitroanisole, and Reichardt's dye) within binary mixtures of polyethylene glycol p-(1,1,3,3-tetramethylbutyl)-phenyl ether (Triton X-100 or TX-100)/organic solvents (2-propanol, hexanol, butyl acetate, THF, toluene, and p-xylene) was extensively explored by using solvatochromism and the quantum theory of atoms in molecules (QTAIM). To be more precise, the polarity parameters, ET N, and Kamlet-Taft parameters, such as the hydrogen bond donor ability (HBD) (α), hydrogen bond acceptor ability (HBA) (β), and dipolarity/polarizability (π∗), have been investigated in selected mixtures at 298 K. All binary mixtures exhibit complex...
Investigation of oxygen barrier properties of organoclay/HDPE/EVA nanocomposite films prepared using a two-step solution method
, Article Polymer Composites ; Volume 30, Issue 6 , 2009 , Pages 812-819 ; 02728397 (ISSN) ; Ramezani Saadat Abadi, A ; Dadfar, M. A ; Sharif University of Technology
2009
Abstract
In this article, oxygen barrier properties of nanocomposite films composed of organoclay (OC), high-density polyethylene (HDPE), and ethylene vinyl acetate (EVA) copolymer have been investigated. The nanocomposite films whose EVA forms a dominant fraction were prepared using the solution method. The dispersion of the OC in the HDPE/EVA blend was improved through taking two-step procedure in the preparation of nanocomposite. First, the OC and EVA were dissolved in chloroform. Then, the resulting product, after evaporating most of the solvent, along with HDPE was dissolved in xylene. The obtained nanocomposite films underwent a number of tests in order to examine their barrier properties...
First-principles study of molecule adsorption on Ni-decorated monolayer MoS2
, Article Journal of Computational Electronics ; Volume 18, Issue 3 , 2019 , Pages 826-835 ; 15698025 (ISSN) ; Berahman, M ; Asgari, R ; Sharif University of Technology
Springer New York LLC
2019
Abstract
The interactions between four different gas molecules (methanol, o-xylene, p-xylene and m-xylene) and Ni-decorated monolayer MoS2 were investigated by means of density functional computations to exploit its potential application as a gas sensor. The electronic properties of the Ni-decorated monolayer MoS2 and gas molecule (adsorbent–adsorbate properties) strongly depend on the Ni-decorated monolayer MoS2 structure and the molecular configuration of the adsorbate. The adsorption properties of volatile organic compound (VOC) molecules on Ni-decorated MoS2 has been studied taking into account the parameters such as adsorption energy, energy bandgap, density of states, and Mulliken charge...
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...
Immersed single-drop microextraction-electrothermal vaporization atomic absorption spectroscopy for the trace determination of mercury in water samples
, Article Journal of Hazardous Materials ; Volume 165, Issue 1-3 , 2009 , Pages 353-358 ; 03043894 (ISSN) ; Naderi, M ; Sharif University of Technology
2009
Adsorption of petroleum monoaromatics from aqueous solutions using granulated surface modified natural nanozeolites: Systematic study of equilibrium isotherms
, Article Water, Air, and Soil Pollution ; Volume 217, Issue 1-4 , 2011 , Pages 611-625 ; 00496979 (ISSN) ; Torabian, A ; Kazemian, H ; Bidhendi, G. N ; Azimi, A. A ; Charkhi, A ; Sharif University of Technology
Abstract
Petroleum monoaromatics including benzene, toluene, ethylbenzene, and xylenes (BTEX) are among the notorious volatile organic compounds that contaminate water and soil. In this study, a surfactant- modified natural zeolite and its relevant granulated nanozeolites were evaluated as potential adsorbents for removal of petroleum monoaromatics from aqueous solutions. All experiments performed in batch mode at constant temperature of 20°C and pH of 6.8 for 48 h. The results revealed that the amount of BTEX uptake on granulated zeolites nanoparticles were remarkably higher than the parent micron size natural zeolite (in the order of four times). The isotherms data were analyzed using five models...
Roles of inorganic oxide nanoparticles on extraction efficiency of electrospun polyethylene terephthalate nanocomposite as an unbreakable fiber coating
, Article Journal of Chromatography A ; Volume 1375 , 2015 , Pages 8-16 ; 00219673 (ISSN) ; Roostaie, A ; Sharif University of Technology
Elsevier
2015
Abstract
In the present work, the roles of inorganic oxide nanoparticles on the extraction efficiency of polyethylene terephthalate-based nanocomposites were extensively studied. Four fiber coatings based on polyethylene terephthalate nanocomposites containing different types of nanoparticles along with a pristine polyethylene terephthalate polymer were conveniently electrospun on stainless steel wires. The applicability of new fiber coatings were examined by headspace-solid phase microextraction of some environmentally important volatile organic compound such as benzene, toluene, ethylbenzene and xylene (BTEX), as model compounds, from aqueous samples. Subsequently, the extracted analytes were...