Liquid–liquid equilibrium data of the solubility curves and tie-line compositions were determined for ternary systems of water+acetyl acetone+propyl acetate at 288.15K, 298.15K and 313.15K and atmospheric pressure. Distribution... more
Liquid–liquid equilibrium data of the solubility curves and tie-line compositions were determined for ternary systems of water+acetyl acetone+propyl acetate at 288.15K, 298.15K and 313.15K and atmospheric pressure. Distribution coefficients were evaluated for the immiscibility region. The reliability of the experimental tie-lines has been confirmed by using Othmer–Tobias and Bachman correlation. The experimental data were fitted using the NRTL and UNIQUAC
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In the present study, reaction crystallization of silver micron and nanoparticles was studied in a batch crystallizer in two different set of experiments by reducing silver in the presence or absence of sodium citrate. From the... more
In the present study, reaction crystallization of silver micron and nanoparticles was studied in a batch crystallizer in two different set of experiments by reducing silver in the presence or absence of sodium citrate. From the experimental determination of crystal size distribution, and with the aid of a mathematical model of the process, nucleation and growth kinetics of silver nanoparticles were determined. Kinetic parameters were determined by fitting the power law expression to the experimental data. Nanoparticle growth rates indicate a diffusion controlled mechanism with a first order dependence on supersaturation, while the observed low dependence of nucleation rate on magma density imply the primary nucleation occurring. Nevertheless, in the synthesis of micron particles magma density was important and agglomeration took place and nucleation, volume crystal growth rates as well as agglomeration kernel were determined.
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Abstract Experimental and thermodynamic modeling results for hydrate dissociation conditions in carbon dioxide + THF + NaCl + water systems were reported. Four different aqueous solutions of THF and NaCl (0.05 mass fraction of NaCl, 0.05... more
Abstract Experimental and thermodynamic modeling results for hydrate dissociation conditions in carbon dioxide + THF + NaCl + water systems were reported. Four different aqueous solutions of THF and NaCl (0.05 mass fraction of NaCl, 0.05 mass fraction of THF: namely solution 1; 0.10 mass fraction of NaCl, 0.05 mass fraction of THF: namely solution 2; 0.05 mass fraction of NaCl, 0.20 mass fraction of THF: namely solution 3; 0.10 mass fraction of NaCl, 0.20 mass fraction of THF: solution 4) were studied in this work. An isochoric pressure – search method was used to perform the measurements. The equilibrium dissociation conditions are reported in the ranges of (0.92–3.89) MPa and (280.9–292.9 K). NaCl acts as an inhibitor in all of the experiences, while THF acts as a promoter. Comparing our data with the same system in the absence of NaCl, a shift is observed toward the left in the equilibrium curve. In addition, this kind of shifting to the left in the curves is more observable at high pressures. In order to predict the equilibrium conditions, a thermodynamic model was developed which uses the Peng-Robinson equation of state and e-UNIQUAC activity coefficient model, for gas/vapor, aqueous electrolyte solution and promoter, respectively. The average absolute deviation of pressure for the model results is in the range of 0.06–0.08 MPa, which confirm the model accuracy.
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Abstract In this paper, magnetic keratin as a new nanocomposite was synthesized to overcome the handling and separation problem coexist with keratin nanoparticles (KNPs). The nanocomposite was prepared by in-situ synthesis of Fe3O4 in a... more
Abstract In this paper, magnetic keratin as a new nanocomposite was synthesized to overcome the handling and separation problem coexist with keratin nanoparticles (KNPs). The nanocomposite was prepared by in-situ synthesis of Fe3O4 in a dilute aqueous solution of KNPs of 0.5 g/L using the co-precipitation method. The synthesized nanocomposite was characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). Magnetic field implementation and XRD pattern confirmed that the nanocomposite was magnetic. The presence of amide I and II as well as Fe─O band in the FTIR analysis of the nanocomposite structure indicated that both Fe3O4 and keratin were present in its structure. Transmission electron microscopy (TEM) images showed that the nanocomposite had a mean diameter of 15.0 nm and a core-shell structure with a mean shell thickness of about 1.3 nm. Based on TGA, it was concluded that only 8.4% of the nanocomposite weight was assigned to keratin. Additionally, the vibrating sample magnetometry (VSM) analysis revealed that the magnetization of the nanocomposite was a little lower than Fe3O4. The nanocomposite also showed a good capability of Cu(II) adsorption as compared to the naked Fe3O4 and KNP by removing up to 98% of Cu(II) from aqueous solution.
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Research Interests: Desalination and Hydrate
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Abstract Hydrate formation has drawn wide-ranging research attention because of its applications in natural gas storage and transportation, refrigeration technology, seawater desalination, gas separation, capturing greenhouse gases, and... more
Abstract Hydrate formation has drawn wide-ranging research attention because of its applications in natural gas storage and transportation, refrigeration technology, seawater desalination, gas separation, capturing greenhouse gases, and energy storage. Also, THF hydrate has been widely investigated in terms of its kinetics, thermophysical properties, and suitability as a replacement for CH4 hydrates in experimental studies. In this work, the kinetics of THF hydrate formation under the impact of an electric field is studied by performing a chemical affinity model. Hence, the effect of an electric field on the chemical affinity model variations involving nucleation temperature and time duration to attain equilibrium needs to be studied from the model point of view. Then, the chemical affinity model under the effect of an electric field is performed for three THF-H2O systems involving solutions containing 10 wt% THF, 19 wt% THF, and 30 wt% THF, and one THF–H2O–SDS system containing 19 wt% THF and 100 ppm SDS. Based on the results, imposing an electric field with a strength of 4.3 × 105 V/m for the mentioned systems causes the nucleation temperature and the hydration reaction time to reach equilibrium to increase. Herein the change in THF consumption versus time in the process of formation and growth of THF hydrate is analyzed by using the chemical affinity model.
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Abstract This paper aims to study the effect of silver nanoparticles on the kinetics of CO2 hydrate growth at different P-T conditions using the molecular dynamics (MD) technique.Three nanofluid models containing 2, 4 and 6 nanoparticles... more
Abstract This paper aims to study the effect of silver nanoparticles on the kinetics of CO2 hydrate growth at different P-T conditions using the molecular dynamics (MD) technique.Three nanofluid models containing 2, 4 and 6 nanoparticles (NPs) as well as a base model (without NPs) were designed to study the effect of nanoparticle concentration on the gas hydrate system. The profiles of potential energy (PE), mean squared displacement (MSD) and density along the simulation box, and the number of CO2 molecules at the hydrate-liquid interfaces, diffusion coefficient, three-body structural order (F3) and also radial distribution function (RDF) were calculated from the simulation. The results revealed that the rate of hydrate growth increases as the temperature increases from 250 K to 260 K at a constant pressure of 30 MPa . A similar trend was also achieved for decreasing the pressure from 30 MPa to 15 MPa at constant temperature of 250 K, however, increasing the temperature to 270 K at 30 MPa decreased again the growth rate.Among the simulation models, the 2-NP fluid model at 260 K and 30 MPa was found to have the highest hydrate growth rate. It was found that nanoparticles have several impacts on the CO2 hydrate system as follows: they could lower the potential energy of the system, increase the peak’s height of the carbon-oxygen and carbon-carbon RDFs, facilitate CO2 dissolution, enhance the diffusion coefficient, and improve the migration of CO2 molecules from the bulk of the solution to the interfaces, and also could physically block the CO2 migration at high concentrations. Finally, form the RDF calculations, the results of our simulation are in good agreement with those reported in the literature with an average error of less than 10%.
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In this study, the induction time of potassium sulf ate Nano particles was measured at 25 ° C and different super saturation in order to nuclea tion, by Acetone anti solvent, Also, the consuming volume of Acetone for nucleation, exa mined... more
In this study, the induction time of potassium sulf ate Nano particles was measured at 25 ° C and different super saturation in order to nuclea tion, by Acetone anti solvent, Also, the consuming volume of Acetone for nucleation, exa mined singly and at the presence of the superficial active material of cetyl tri methyl ammonium bromide(CTAB) and sodium citrate. Additionally, the surface tension of potas sium sulfate nano particles has calculated at the presence of CTAB surfactant, by use of class ic theory of nucleation. The results acquired that, at the presence of Acetone, the indu ction time rises by increasing the amount of super saturation, But at the presence of surfactant, the induction time is decreased by increasing of super saturation. In rel ation with the surface tension and also at the presence of CTAB, the surface tension decrea sed by increasing of potassium sulfate concentration. Generally, by evaluating of done st udies, we can say that, eventually, the presence of ...
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Abstract As a noteworthy salt hydrate, sodium sulfate decahydrate or Glauber salt can be used as a phase change thermal energy storage material. Kinetic parameters of sodium sulfate decahydrate salt solution are evaluated experimentally.... more
Abstract As a noteworthy salt hydrate, sodium sulfate decahydrate or Glauber salt can be used as a phase change thermal energy storage material. Kinetic parameters of sodium sulfate decahydrate salt solution are evaluated experimentally. Instead of the traditional polythermal and isothermal methods, a novel constant temperature experimental method (based on the turbidity titration) was adopted to experimentally illustrate the induction time and metastable zone width, in unseeded batch crystallization for sodium sulfate decahydrate salt solution at different temperatures (7, 9, 10, 13, 16, 19, 22 °C) and supersaturation ratio (1.01–1.43). We determined crystallization thermodynamics parameters, solubility, and supersolubility, of sodium sulfate decahydrate salt solution under atmospheric pressure and at different temperatures. The solubility data could be well fitted by the solubility carve of sodium sulfate decahydrate in the phase diagram of sodium sulfate. Statistical analysis shows that there was consistency in the result data of solubility. Two models, classical nucleation theory (primary homogeneous) and secondary nucleation, were employed to analyze the experimental data. The secondary nucleation model helped determine the order of nucleation and nucleation kinetic constants.
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In this study a low-width MoS(2) ribbon has been used for probing the electronic structure and local magnetic moment near vacancies. A theoretical study with the full-potential Density Functional Theory (DFT) approach (Wien2K code) have... more
In this study a low-width MoS(2) ribbon has been used for probing the electronic structure and local magnetic moment near vacancies. A theoretical study with the full-potential Density Functional Theory (DFT) approach (Wien2K code) have shown that when the dimension of MoS(2) is reduced from 2-D to 1-D the nonmagnetic semi-conductor MoS(2) becomes a magnetic conductor. Our study has shown that a vacancy on the S-edge with 50% coverage intensifies the magnetization of the edge of the MoS(2) nanoribbon but such a vacancy on S-edge with 100% coverage causes this magnetic property to disappear. It is concluded that in both of them, there are positive or negative strong gradients of local magnetic moment near the vacancy. This may explain why lattice defects are essential for catalysis processes.
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In this research, the changes in bubbles diameter and number that may occur due to the change in heat flux of pure water during pool boiling process. For this purpose, test equipment was designed and developed to collect test data. The... more
In this research, the changes in bubbles diameter and number that may occur due to the change in heat flux of pure water during pool boiling process. For this purpose, test equipment was designed and developed to collect test data. The bubbles were graded using Caliper Screen software. To calculate the growth and nucleation rates of bubbles under different fluxes, population balance model was employed. The results show that the increase in heat flux from q=20 kw/m2 to q=102 kw/m2 raised the growth and nucleation rates of bubbles.
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The effects of anionic surfactants sodium dodecyl sulfate (SDS) and linear alkyl benzene sulfonate (LABS), cationic surfactant cetyl trimethyl ammonium bromide (CTAB) and non-ionic surfactant ethoxylated nonylphenol (ENP) on the... more
The effects of anionic surfactants sodium dodecyl sulfate (SDS) and linear alkyl benzene sulfonate (LABS), cationic surfactant cetyl trimethyl ammonium bromide (CTAB) and non-ionic surfactant ethoxylated nonylphenol (ENP) on the formation, dissociation and storage capacity of methane hydrate have been investigated. Each surfactant was tested with 3 concentrations 300, 500 and 1000ppm and it has been found that SDS, when
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ABSTRACT The effect of 1,4-dioxane on ethylene hydrate was investigated at three additive molar concentrations of 2.78%, 5.56% and 8.34%. The equilibrium conditions for hydrate dissociation were obtained by step heating method. The... more
ABSTRACT The effect of 1,4-dioxane on ethylene hydrate was investigated at three additive molar concentrations of 2.78%, 5.56% and 8.34%. The equilibrium conditions for hydrate dissociation were obtained by step heating method. The results showed that addition of 1,4-dioxane concentration increases the pressure of hydrate dissociation. Diagram of Ln(Peq) vs. Teq demonstrated that system of 1,4-dioxane + ethylene + water form ethylene hydrate with structure I. In fact 1,4-dioxane cannot participate in hydrate structure because ethylene molecules are not a good help gas for occupation of S-cages in structure II. So, in this condition only ethylene hydrate with structure I could be formed. The experimental results on hydrate formation indicted that 1,4-dioxane accelerates the hydrate growth rate by increasing the solubility of ethylene in water and a maximum storage capacity of (VSTP/VH) = 146 is obtained in a critical dioxane concentration of 5.56% by mole. Also hydrate dissociation experiments revealed that maximum dissociation percentage is related to pure water (48%) and 1,4-dioxane decreases dissociation percentage of ethylene hydrate.
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By using response surface methodology, Batch shaking biosorption of cobalt (II) experiments were conducted in order to examine the combined effects of operating parameters. The results indicate that magnesium nitrate performed as an... more
By using response surface methodology, Batch shaking biosorption of cobalt (II) experiments were conducted in order to examine the combined effects of operating parameters. The results indicate that magnesium nitrate performed as an effective biosorbent surface modifier, which increases the rate of adsorption capacity. At optimal conditions (initial pH 7.0, temperature 45◦C, biosorbent concentration 0.1 g/100ml, and initial cobalt concentration 300mg/l for Mg-treated biomass) the biosorption capacity of the algae for cobalt was found to be 80.55 mg/g. The Langmuir and Freundlich isotherms were applied to the equilibrium data. The results are best fitted by the Freundlich model. Evaluation of the experimental data in terms of biosorption dynamics showed that the biosorption of cobalt (II) onto algal biomass followed the pseudo-second-order dynamics well. Using the thermodynamic equilibrium coefficients obtained at different temperatures, the thermodynamic parameters (ΔG◦, ΔH◦ and ΔS◦...
Research Interests: Chemistry and Biosorption
In this research, the capability of neural networks in modeling and learning complicated and nonlinear relations has been used to develop a model for the prediction of changes in the diameter of bubbles in pool boiling distilled water.... more
In this research, the capability of neural networks in modeling and learning complicated and nonlinear relations has been used to develop a model for the prediction of changes in the diameter of bubbles in pool boiling distilled water. The input parameters used in the development of this network include element temperature, heat flux, and retention time of bubbles. The test data obtained from the experiment of the pool boiling of distilled water, and the measurement of the bubbles form on the cylindrical element. The model was developed based on training algorithm, which is typologically of back-propagation type. Considering the correlation coefficient obtained from this model is 0.9633. This shows that this model can be trusted for the simulation and modeling of the size of bubble and thermal transfer of boiling. Keywords—Bubble Diameter, Heat Flux, Neural Network, Training Algorithm.
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Abstract The behavior of silver nanoparticles (AgNPs) under an applied electric field depends primarily on their stabilizing agent. This research aimed at investigating the behavior of AgNPs and their stabilizers under the... more
Abstract The behavior of silver nanoparticles (AgNPs) under an applied electric field depends primarily on their stabilizing agent. This research aimed at investigating the behavior of AgNPs and their stabilizers under the electrocoagulation (EC) process. In two separate experiments, sodium citrate and polyvinylpyrrolidone (PVP) were used as the nanoparticles’ stabilizers. Stability of the particles was studied while applying an electrical current with various voltages. Efficiency of the EC process was investigated for these different AgNPs sols. In the case of sodium citrate for various voltages, the plasmon resonance peak of the sample was disappeared after applying the electric field for 90 min, reflecting the removal of AgNPs in the sol by 99.91%. In the case of PVP for various voltages of the EC process for 10 min, the absorbance peak disappeared, and removal efficiency of AgNPs reached 99.98%. Effect of stabilizer concentration on the EC process was investigated. As sodium citrate concentration increased, the stability of AgNPs under an equall applied electric field increased, while the increase of the PVP concentration did not influence on the stability of AgNPs. Kinetic of AgNPs removal was also studied.
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The purpose of this study was to investigate the effect of process parameters (silica nanoparticle concentration (NP), biosurfactant (BS) concentration and salinity) as well as their synergistic effects on oil recovery in simultaneous... more
The purpose of this study was to investigate the effect of process parameters (silica nanoparticle concentration (NP), biosurfactant (BS) concentration and salinity) as well as their synergistic effects on oil recovery in simultaneous flooding.
Research Interests: Materials Science and RSC
ABSTRACT In this paper, the impact of the mixture of sodium dodecyl sulfate (SDS) + multi-wall carbon nanotubes (MWCNTs) + β-cyclodextrin on the quantity and initial rate of methane dissolved in water is investigated. The experiments were... more
ABSTRACT In this paper, the impact of the mixture of sodium dodecyl sulfate (SDS) + multi-wall carbon nanotubes (MWCNTs) + β-cyclodextrin on the quantity and initial rate of methane dissolved in water is investigated. The experiments were performed at a temperature range of 278.15–303.15 K and an initial pressure of 0.5 MPa. The experimental results show that simultaneous utilization of β-cyclodextrin (0.01 mass fraction), MWCNTs (0.0005 mass fraction), and SDS (0.001 mass fraction) at 278.15 K increases the amount and the rate of methane dissolution in water by 29.90% and 173.78%, respectively, compared to pure water. An increase in the temperature decreases the quantity and the initial rate of methane dissolution in all solutions containing additives. However, no consistent relationship is observed between the temperature and the enhancement percentage of solubility of methane in solutions containing additives.
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Prediction of the nucleation mechanism is one of the most critical factors in the design of a crystallization system. Information about the nucleation mechanism helps to control the size, shape, size distribution, and purity of the... more
Prediction of the nucleation mechanism is one of the most critical factors in the design of a crystallization system. Information about the nucleation mechanism helps to control the size, shape, size distribution, and purity of the produced crystals. When the crystallization method is used for producing nanoparticles, the nucleation mechanism should be predicted. In this study, an empirical correlation based on the induction time, classical nucleation theory, and Kashchive model is used to determine the nucleation mechanism. Nanoparticles are produced in the presence of Cetyl Trimethyl Ammonium Bromide (CTAB) and the effect of CTAB on the induction time and the interfacial tensions of potassium chloride nanoparticles have been investigated. The obtained results demonstrated that the nucleation mechanism of potassium chloride nanoparticles is heterogeneous. This method is simple and can be applied at ambient conditions for synthesis other mineral nanoparticles. It can also be applied...
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In the present study, silver nanoparticles were synthesized by decomposition of AgNO3 via gelcasting. Methacrylamide was used as a low toxic monomer for gel formation. Effect of monomer content (MAM), cross-linker to monomer ratio... more
In the present study, silver nanoparticles were synthesized by decomposition of AgNO3 via gelcasting. Methacrylamide was used as a low toxic monomer for gel formation. Effect of monomer content (MAM), cross-linker to monomer ratio (MBAM/MAM), silver salt to monomer ratio (AgNO3/MAM), duration of calcination, and temperature of calcination were investigated to optimize the size of nanoparticles. Taguchi method was applied to study the effect of gelcasting parameters on the size of silver nanoparticles. Mentioned parameters were surveyed at four levels and based on the Taguchi method 16 experiments were carried out. Silver nanoparticles were characterized, and average particle sizes were measured by SEM analysis. By using the signal to noise ratio (S/N) analysis of the results, it is revealed that monomer content is the most effective parameter on size of particles. Also, optimal values of monomer content, cross-linker to monomer ratio, silver salt to monomer ratio, duration of calcin...
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Selecting process conditions for the dilution crystallization of sulfur in ethanol +toluene mixture for production of sulfur Nanocrystals is studied in the present work. The crystallization process is carried out using the anti-solvent... more
Selecting process conditions for the dilution crystallization of sulfur in ethanol +toluene mixture for production of sulfur Nanocrystals is studied in the present work. The crystallization process is carried out using the anti-solvent technique to obtain sulfur precipitations in solution. Using this process, the sulfur solubility is decreased in toluene as co-solvent. Although the co-solvent and anti-solvent are miserable in any proportion. The solubility curve of sulfur has been measured in ethanol + toluene mixture. Since the purpose is to produce nano particles, we have determined the shape and size of particles by crystals filtration from solution and to do SEM and TEM tests. The feasibility of the proposed scheme and operating conditions are confirmed by experimental studies in a crystallizer at 25 o C constant temperature.
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Nickel-molybdenum oxidebimetallic nanoparticles were synthesized in ethylene glycol using the microwave irradiation technique. According to the results, successive reduction of nickel and molybdenum ions, followed by thermal treatment of... more
Nickel-molybdenum oxidebimetallic nanoparticles were synthesized in ethylene glycol using the microwave irradiation technique. According to the results, successive reduction of nickel and molybdenum ions, followed by thermal treatment of obtained nanoparticles led to formation of core-shell structured nickel-molybdenum oxide nanoparticles. According to the results, the thickness of the shell and core were 5 and 40 nm, respectively. The structure and composition of nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-vis spectroscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS).