نشریه شیمی و مهندسی شیمی ایران
سال چهلم شماره 3 (پیاپی 101، پاییز 1400)

The preparation of nanocomposite membranes containing Carbon NanoTubes (CNTs) has been one of the prevalent subjects for research. Despite drawing attention to studying it, these efforts were insufficient in comparison with its prospect as a new technology. The importance of using carbon nanotube membranes, especially in water treatment and desalination applications, has persuaded all countries to focus more and more on relevant research. In recent decades, carbon nanotubes membranes are a major branch in the field of membrane technologies because of the discovery of new properties of the CNTs in different conditions and various substrates, the effect of the CNTs orientation and the sorting on the nanocomposite properties, and new interactions with the pollutants and the salt molecules in the water purification process. In this area, new methods for synthesis, the use of novel materials and the clarification of the mechanisms are the most important issues that cause accessibility of cheaper, more flexible, and more efficient methods. The review consists of the preparation of polymeric nanocomposites containing the CNTs, mechanism, orientation, and arrangement methods of carbon nanotubes in membrane structure, as well as the recent application of these membranes for water treatment and desalination. The findings of this review might lead to more curiosity and investigation regarding the above matters.

Chromium contamination in natural water has posed a significant threat to global health due to its toxicity and carcinogenicity. Adsorption technology is an easy and flexible method for chromium removal with high efficiency. Among these, the synthetic approaches based on nanotechnology due to unique structural characterization and application are of great importance. In this article, polystyrene (PS) nanoparticles were used as polymer support and magnesium-aluminum layered double hydroxide (MgAl-LDH) nanostructures were applied as adsorbent. The PS nanoparticles were synthesized via emulsion polymerization of styrene monomer. The as-prepared PS nanoparticles were used as the polymer support to be covered by the MgAl-LDH nanostructures prepared via a hydrothermal approach. The as-prepared MgAl-LDH@PS core-shell nanostructures are characterized by SEM, TGA, and FT-IR analysis. Batch adsorption of Cr(VI) was carried out to evaluate the adsorption efficiency, isotherm, and kinetic studies of the MgAl-LDH@PS nanostructures. On the basis of Langmuir model, a high maximum Cr(VI) adsorption capacity (Qmax) of 765 mg/g with coefficient correlation (R2) of 0.9951 was achieved in batch Cr(VI) removal study. Furthermore, based on the pseudo-second-order kinetic model, the pseudo-second-order rate of 0.1372 mg/(g min) with R2= 0.9975 was achieved. In addition, the results of the stability, as well as the regeneration of the adsorbent, showed that the MgAl-LDH@PS nanostructures can be considered unique adsorbent.

Nowadays, the separation of heavy metals from industrial wastewater is one of the most important issue to protect the environment. The core-shell structure of Fe3O4 @ SBA-15 is a proper solid base for functionalization and separation of mixture reaction. The SBA-15 nanoparticles have a very high surface area that can be functionalization with the huge amount of organic groups. In this project, magnetic nanoparticles were synthesized with the co-precipitation method then coated with high-ordered surface area SBA-15 then functionalized with the organic ligand. The surface of these materials functionalized with 3-(2-aminoethylamino)-propyl amine. In order to the characterization of nanocomposite properties, some techniques such as IR, TGA, SEM, XRD, and BET analyzes were used. After synthesizing and characterization of Fe3O4@SBA-15@(CH2)3- NH-(CH2)2-NH2, this compound was used for the separation of heavy metals from in vitro manipulation matrix. The advantages of these materials can be noted such as high surface area, magnetic properties, and recoverable and non-toxic properties.

For nano-fibrous bio-scaffolds like wound dresses, control of microstructural factors such as fiber diameter, number, and size of cells is important. In this study, the microstructure is investigated from data from BET and density tests. The voltage of the electrospinning process is one of the most important parameters for the control of the microstructure. To study a wider voltage range, the existing electrospinning device is upgraded to 70 kV. In this research, the samples are spun from two types of polymers of different molecular weights in the range of 20 to 40 kV. For increasing biocompatibility and biodegradability, the polymers are purified with the phase separation method. This purification is investigated with FT-IR and melting point tests. The result of the study of the microstructure shows that, as the electrospinning voltage increases, firstly, the diameter of the fiber increases, the number of cells decreases, and the size of the cell increases. Then, the diameter of the fibers  decreased, the number of cells increased and the size of the cells decreased. In most electrospinning voltages, the mats produced from higher molecular weight polymer have a smaller fiber, a larger cell number, and a smaller cell size. But in the voltage of 25 and 40 kV, the mats have inverse results. The FT-IR and melting point results show that the phase separation method is effective for purification. Finally, it can be said that the effect of the voltage on the microstructure parameter up to 30 kV is different thereafter.

In this work, superparamagnetic nanocomposite of Manganese ferrite was synthesized, using a co-precipitation method, and to prevent oxidation and increase of OH-functional groups on the surface, nanoparticles were reacted with tetra-orthosilicate and Silica coating was created on the surface of nanoparticles. In order to establish a chemical bond in subsequent reactions, the surface of the nanoparticles were covered and functionalized with 3-amino-propyltrimetoxycycline (APTMS). On the other hand, Multi-Walled Carbon NanoTubes (MWCNTs) with a diameter of 8 nm, increase the reactivity was reacted and functionalized with HNO3 Followed by thionyl chloride. Finally, the magnetic nanoparticles of manganese ferrite with an amine functional group are reacted with acylated  MWCNTs. Magnetic nanoparticles were identified using FT-IR spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Vibrating Sample Magnetometers  (VSM), X-Ray Diffraction (XRD) and Raman spectroscopy (RAMAN).

The development of low-cost, high-performance catalysts and the use of renewable sources for use in oxygen reduction and evolution reactions have received considerable attention. In this study, using an efficient and single-stage method using nickel-cobalt oxides and a material obtained from southern cattail or karrapo (KP) as available biomass, a catalyst with nano-fiber structures was synthesized (NFKP/Ni-Co). In order to synthesize the NFKP/Ni-Co, the Ni-Co compound, by sol-gel method in the autoclave at 200°C for 12h, was loaded on the surface of KP, and finally, it was pyrolyzed at 700°C for 3h in an argon atmosphere. The structure, composition, morphology, and catalytic activity of the synthesized nanocomposites have been investigated. The TEM studies prove the formation of 20nm of nanoparticles of Ni-Co oxides on the surface of nanofibers. Here, KP acted as a boat-like platform in which Ni-Co oxides were loaded. Due to the synergistic effect between KP and Ni-Co oxides, NFKP/Ni-Co nanocomposite exhibit remarkable catalytic activity for the oxygen reduction reaction with an initial potential of -0.15V, half wave potential of -0.32V, peak current density of 0.25 mA/cm2 and limiting current density of 0.23 mA/cm2 which is comparable to commercial Pt/C catalyst.

In this study, supported tris(hydroxymethyl)methane ammonium acetate ionic liquid on silica gel (SiO2-THMAA) was synthesized for the first time. SiO2-THMAA was prepared by the reaction of 3-chloropropylsilica with  tris(hydroxymethyl) aminomethane followed by ion exchange with acetate. SiO2-THMAA was characterized by FT-IR, BET, and elemental analysis. Also, to explore the catalytic activity of SiO2-THMAA in organic reactions, the synthesis of α,β-unsaturated compounds was investigated in the presence of SiO2-THMAA as a heterogeneous catalyst at room temperature. The desired products were produced in high yields and short times in mild reaction conditions. SiO2-THMAA was also recovered and reused after the three reaction cycle without a significant decrease in catalytic activity.

ZSM-11 Zeolite was successfully synthesized using a seed-assisted method and a proposed template of N,N-diethylaniline. In addition, the effect of the silicon-to-aluminum ratio was investigated for seeds and the optimum ratio of 10 was obtained. Synthesized zeolites were identified using FT-IR, EDX, SEM, BET, and XRD techniques. Synthesized zeolite as a heterogeneous catalyst in the oxidative desulfurization process was used for the fuels model including n-heptane and dibenzothiophene. In order to obtain optimal reaction conditions, the effect of temperature and amount of catalyst was studied and a temperature of 100 and amount of 0.05g was chosen as optimum temperature and amount of catalyst and the effect of time in optimal conditions were investigated for different catalysts. The percentage of conversion of dibenzothiophene ion exchangeable zeolites with different intermediate metals such as molybdenum, vanadium, lanthanum, cobalt, copper, and cerium was calculated by gas chromatography and compared with each other. The results show that the Mo/ZSM-11 catalyst has high oxidation activity in comparison with other catalysts in the oxidative desulfurization reaction.

In this study, 1,3-dimethoxy-2,2-bis(methoxymethyl)propane (Yield: 85%), 5,5-bis(methoxymethyl)-1,3-dioxane (Yield: 89%), 1-methoxy-2,2-bis(methoxymethyl)butane (Yield: 98%), 1,3-dimethoxy-2-((3-methoxy-2,2- bis(methoxymethyl)propoxy)methyl)-2-(methoxymethyl)propane (Yield: 78%) and 1-(2,2-bis(methoxymethyl)butoxy)-2,2-bis(methoxymethyl)butane (Yield: 93%) as the new internal electron donors were synthesized using the Williamson reaction. The synthesized ethers were characterized by FTIR, NMR, and GC techniques. The MgCl2-supported Ziegler-Natta catalysts were prepared with optimum ID/Mg molar ratio of synthesized internal electron donors, and also without the internal electron donor. Then, polymerization of propylene was carried out with the prepared catalysts and also with industrial Ziegler-Natta catalyst, with and without the external donor, in the presence of triethylaluminum as a co-catalyst and hydrogen as a chain transfer agent. Effects of ethers compounds as the new internal donors on the catalytic activity, Hydrogen response of the prepared catalysts, xylene solubility, weight-average molecular weight, molecular weight distribution, crystallinity degree, and thermal properties of the produced polypropylenes were examined. Then the performance of the prepared MgCl2-supported Ziegler-Natta catalysts with new internal electron donors on the properties of produced polypropylenes were compared with each other and also, with industrial Ziegler-Natta catalyst containing diisobutyl phthalate internal donor and catalyst without the internal electron donor.

In recent years, interest in the synthesis and use of boron-nitride (BN) structures has increased due to their distinct properties. These properties include low density, high-temperature stability, oxidation resistance, high dispersion stability, high shear force (compared to its equivalent structure, graphene), high absorption capacity, and wide bandwidth. In this study, using the Density Functional Theory (DFT), the effect of the Electric Field (EF) on Na and Na + adsorption on BN nanosheets as the anode in sodium batteries was investigated. The results showed that Na+ adsorption was much stronger than Na and the cell voltage (Vcell) increased linearly with increasing electric field. In the absence of a field, Vcell = 1 / 13V, it increases by increasing the field to Vcell = 1 / 87V, which results in high energy storage in a long discharge battery.

A new class of hexagonal graphene-like lattice with an sp2-bonding configuration consisting of Si, B, and N with covalent bonds in the intralayer and van der Waals bond in the interlayer. In this research, three possible atomic arrangements for the Si2BN in the bulk state have been studied, and then the structural and electronic properties of the most stable crystal structure of Si2BN have been investigated in the framework of density functional theory with different approximations such as PBE, LDA, PBEsol, Vdw, HSE. The calculations have been performed by the Projector Augmented Plane Wave (PAW) method as implemented in the Quantum Espresso (QE) package. The most stable crystal structure of Si2BNhas been indicated by the calculation of the Energy–volume curve, Cohesive Energy, Formation energy, bond length, and enthalpy of different crystal structures of Si2BNfor different pressure. The structure is found to be metallic in bulk and monolayer state caused by the presence of Si atoms. By considering the orbitals of each atom in creating the total density of states, it is obvious that the p orbital of B and Si1 atoms at EF possess the majority of contributions in the valence and conduction bands, respectively. In creating the monolayer structure, the optimal Vacuum for all approximations is considered to be 12Ao. It should be noted that monolayer Si2BNcalculations have also shown metallic properties but the length of the bond has been changed. In creating the bilayer structure, the optimal interlayer separation and interaction energy have been investigated.

Due to the wide range of pharmacological and biological properties of thiobarbiturates, a great effort has been devoted to the synthesis of the thiobarbituric acid derivatives. In this work, the electrochemical oxidation of N,N-diethyl-p-phenylenediamine has been studied in the presence of thiobarbituric acid as the nucleophile in aqueous solutions, using cyclic voltammetry and controlled-potential coulometry. The results indicate that the electrochemically generated diimine participates in a Michael-type addition reaction with thiobarbituric acid and via an ECE mechanism converts to the product. In this work, the new thiobarbituric acid derivative is provided with high yield, without reagents and catalyst at a carbon electrode. Density Functional Theory (DFT) calculations were used to confirm the structure of the product and simulate the HNMR and CNMR spectra.

A septet series of monoalkyldithiocarbamte compounds of formula R–NHCSSNa (R = methyl, ethyl, propyl, butyl, hexyl, octyl, and nonyl) were synthesized via the reaction of corresponding amine, CS2, and NaOH with 1:1:1 molar ratios in acetone-water or acetone at 0 ºC. These compounds were characterized using spectroscopic methods including FT-IR, 1H NMR, UV-Vis, and nonspectroscopic methods such as elemental analysis, molar conductivity, and decomposition temperature measurements. From the reaction of each of these compounds with Ni(NO3)2·6H2O with 2:1 molar ratio in aqueous medium seven dithiocarbamte complexes were prepared. The synthesized complexes were also characterized by the above spectroscopic and nonspectroscopic methods. Based on the obtained results it can be proposed that each dithiocrbamte compound acts as a bidentate ligand and coordinate via its sulfur atoms to Ni2+ ion. The geometry around Ni2+ is square planar.

A septet series of monoalkyldithiocarbamte compounds of formula R–NHCSSNa (R = methyl, ethyl, propyl, butyl, hexyl, octyl, and nonyl) were synthesized via the reaction of corresponding amine, CS2, and NaOH with 1:1:1 molar ratios in acetone-water or acetone at 0 ºC. These compounds were characterized using spectroscopic methods including FT-IR, 1H NMR, UV-Vis, and nonspectroscopic methods such as elemental analysis, molar conductivity, and decomposition temperature measurements. From the reaction of each of these compounds with Ni(NO3)2·6H2O with 2:1 molar ratio in aqueous medium seven dithiocarbamte complexes were prepared. The synthesized complexes were also characterized by the above spectroscopic and nonspectroscopic methods. Based on the obtained results it can be proposed that each dithiocrbamte compound acts as a bidentate ligand and coordinate via its sulfur atoms to Ni2+ ion. The geometry around Ni2+ is square planar.

Carbon Dioxide exists in some gases like natural gas and synthesis gas can make some problems such as reducing heat value, corrosion, and environmental problems in petrochemical like ammonia plants. Using hollow fiber membrane contactors with a suitable absorbent liquid is one of the separation methods in which, cation and anion modification can cause to approach a desired absorbent liquid and higher efficiency. This study's purpose is the modeling of carbon dioxide physical absorption from CO2/N2 mixture through hollow fiber membrane contactors using ionic liquids [Emim][EtSO4]. Mass transfer in the gas, membrane, and liquid phases consists of some partial differential equations that can be solved by numerical solution simultaneously. The model is validated with -Water experimental data due to the lack of data for CO2-Ionic liquids in the literature and it was found that the model with a mean error of about 7.5% was in good agreement with the experimental data which would be an appropriate model to predict the physical CO2 absorption in this study. After validation, the effects of parameters like liquid and gas flow rates, temperature, CO2 molar percentage in the feed gas, the membrane specification, non-wetting, and complete wetting of the membrane are investigated on absorption. The results showed that at a constant fluid flow rate of 25 mL/min, the presence of ionic liquid absorbed about 40% of the CO2 in the inlet gas and an increase of 30 ml/min in the presence of ionic liquid also increased the Carbon dioxide absorption by 15%. Increasing the wettability from zero to 100% will also reduce the CO2 removal efficiency by approximately 15%.

In the current paper, a three-dimensional, steady-state model has been introduced for novel proton exchange membranes (PEM) containing dicationic ionic liquids appropriatefor elevated temperature fuel cells under an anhydrous environment. Development of such a model requires utilizing the 3D geometry and detailed mesh grid and discretization of momentum. Mass and electric charge balance equations were solved based on the information obtained from electrical and electrochemical models within various areas of the cell such as porous electrodes, gas channels, and the solid parts and current collector, especially. Additionally, a description of the electrochemical reactions on the active sites of the anode and cathode electrodes, and ions' movement through the electrolyte is considered. The equations were solved by applying a finite element method solver. Finally, the results of the model are compared with the experimental data (current density-voltage graph). This graph shows a good correlation between the model and experiments validating the present simulation. This model is also able to predict PEMFC behavior under different operational conditions

Considering the strict laws that have been established to reduce combustion pollution and control, it is necessary to consider a new approach to energy supply in the future. Accordingly, hydrogen can be introduced as an alternative fuel to fossil fuels because this energy source is very compatible with the environment and when it reacts with oxygen as a fuel, it produces only water. Also, hydrogen is an important chemical reserve in many chemical industries. The partial oxidation process of hydrocarbons is one of the important applications of the internal combustion. It is a porous medium for synthesis gas production and hydrogen production. Considering the various industrial methods for producing hydrogen in high capacities, attention has been directed to the processes that are in small capacity and are suitable from the economic point of view. Partial oxidation processes in porous media are among these processes. In this study, along with the theoretical investigation of the partial oxidation of methane in the porous medium, modeling was done for a tubular reactor filled with porous medium materials. In the next step, investigating the effects of porous medium conditions, including the structural characteristics of materials such as particle diameter, porosity, and physical changes of the reactor, including the diameter and length of the reactor, and finally, the equivalence ratio of fuel and air, and changes in the intensity of the fuel inlet flow with an approach to producing more Hydrogenation is done.

The main goal of this research is the modeling and optimization of the ethylene oxychlorination reactor in the Arvand Petrochemical Complex. In this process, the dichloroethane is produced through the oxychlorination of ethylene on CuCl3 supported Al2O3 catalyst. The ethylene oxychlorination reaction occurs in a fluidized bed reactor equipped with a heat exchanger to control operating temperature. In the industrial plant, the oxychlorination and direct chlorination processes are in parallel and produced HCl in the direct chlorination and EDC cracking units fed to the oxychlorination reactor. In this research, the oxychlorination reactor is modeled based on the mass and energy balance equations at steady-state conditions. Due to fluid specifications and flow regime, a two-phase flow regime including bubble and emulsion phases with mass transfer between phases is selected to simulate the reactor. To prove the accuracy and precision of the considered model and assumptions, the simulation results are compared with the plant data. Then, an optimization problem is programmed to maximize the dichloroethane production rate based on the design and operating limitations considering feed temperature, coil temperature, operating pressure, and mass flow rate of hydrogen chloride and oxygen as decision variables. The simulation results show that applying the optimal operating condition on the system increases dichloroethane production from 128.7 to 141.3 mol/s.

The main contribution of this work is the development of a control system with improved robustness against the feed composition disturbances in a high-purity distillation column separating the mixture of water and 40 mol% methanol. Despite the superior performance of an inferential control system with one temperature measurement along with a constant reflux-to-feed ratio in comparison to a fixed reflux ratio, however, it fails to provide acceptable performance. Methanol feed composition is taken as a Gaussian variable to obtain a more robust single-end control system. The set of decision variables is constructed considering the design parameters and the set points of the PI controllers. The first and second moments of the constraints and objective function are provided using the unscented transform for the solution of the stochastic optimization problem in the chance-constrained sense. The dynamic responses of the modified single-end control system against unmeasured disturbances in feed composition confirm the effectiveness of the proposed algorithm since product quality can be guaranteed to lie above the desired purity.

In this study, heat transfer and pressure drop through the four-row fin tube bundle with annular elliptical fins in a triangular layout were investigated. Five different geometries in three fin densities for four different Reynolds numbers were simulated. For circular fins, results are in good agreement with empirical equations in predicting pressure drop and heat transfer. In this regard, the elliptical fins were also examined. It was found that the Nusselt numbers in horizontal elliptical fins are the least and in vertical are the highest. It was also found that pressure drop in the circular fins is higher than in horizontal or vertical elliptical fins and the vertical elliptical fins in comparison with circular fins with the same vertical diameter, exert less pressure drop. Furthermore, although the heat transfer coefficient in horizontal elliptical fins is slightly less than in circular fins, the pressure drop can be as much as 70%. The performance evaluation criterion shows that the circular fin performance is much lower compared with the elliptical fin. Finally, equations are proposed to predict the pressure drop and heat transfer coefficient for elliptical fins relative to circular fins

One way to progress towards sustainable energy is to use solar energy in the world. Iran also has great potential for the use of solar energy, but identifying suitable areas for the construction of solar power plants is an important issue. The purpose of this study is to evaluate the solar energy potential of 9 provincial centers in Iran with 3 multi-criteria decision-making methods Simple Additive Weighting, TOPSIS, and ELECTRE. In this regard, the three main criteria of installation location, weather conditions, and risk have been used, which include 11 sub-criteria and were weighed by the Shanon entropy method. In this weighting, the highest and lowest weights were allocated to population criteria and horizontal radiation, respectively. The results of prioritization also show that Zahedan has priority over other options in all three methods. Zahedan's score in the Simple Additive Weighting method is 0.488904, and in the TOPSIS method is 0.8485 and in the ELECTRE method, Zahedan and Tabriz both with 5 advantages over other Options are a priority, also Tehran was selected as the worst option for the construction of solar power plants, and the score of this option in the Simple Additive Weighting method is 0.167015, in the TOPSIS method 0.4452316 and the ELECTRE method, along with Kerman, without having superiority over other options, were in the last priority. Also, in 6 different cases, sensitivity analysis was performed on the presented models. The results of the sensitivity analysis show that the TOPSIS method is less sensitive to the weights of the indicators than the other two methods.

In this study, gas phase holdup in a gas-liquid bubble column reactor was experimentally studied. To conduct experiments, a bubble column with a height of 54 cm and a diameter of 10.4 cm was applied. The studied systems include water-air, Gasoline-air, and Behran oil-air. Experiments were carried out in the range of 400-50 rpm agitator. Based on the Buckingham π theorem, a semi-experimental model for gas phase holdup was presented. The results showed that with increasing viscosity from 0.001 to 0.0136 gas phase holdup loss due to high adhesion of bubbles at high viscosity and also the increase of bubble size at the output from the distributor decreases from 0.41 to 0.333. Among the selected systems, the gas phase holdup of the gas-air system was maximized. The results also showed that in materials with low viscosity, the gas phase reduction was due to the formation of liquid vortex movement and air canalization by the agitator. The best agitator speed to increase the gas phase holdup at water and oil are 150 and 400 rpm, respectively.

Water in crude oil emulsions in the upstream oil industry causes serious problems such as corrosion and precipitation. Therefore, it is of crucial importance to demulsify and separate water at the production site. Demulsifiers’ performance is evaluated by its demulsification efficiency, cost, and biocompatibility. Restrictive environmental regulations have resulted in an ongoing effort to identify and characterize new demulsifiers which offer biodegradability while maintaining demulsification efficiency. In this study, biocompatible and biodegradable cellulosic polymers with trade names Walocel, Cellulose Acetate, Methocel-K3, and Methocel-E5 were used as demulsifiers. Demulsifiers’ performance was evaluated by bottle test using crude oil from the Sarvestan oil field. The initial tests revealed that Walocel and Methocel-E5 have better performance as compared with Cellulose acetate and Methocel-K3. It was found that increasing temperature up to 80 ⁰C and increasing demulsifier concentration up to 3000 ppm results in faster and more efficient demulsification. 90% separation of water at 80 ⁰C and a demulsifier concentration of 3000 ppm was achieved within 2 hours by Methocel-E5 while the same separation took 4 hours for Walocel. After 12 hours of demulsification at 80 ⁰C and a demulsifier concentration of 3000 ppm, Walocel and MEthocel-E5 could demulsify and separate 99% and 98% of the initial water respectively

Acid fracturing is one of the most efficient stimulation techniques in carbonate reservoirs. In gas condensate reservoirs, this technique might significantly decrease liquid hold-up around the wellbore. That is the decrease in flow resistance makes it possible to produce from a fractured well at a higher bottom-hole pressure. This article provides a series of developed correlations for the estimation of the effective wellbore radius of an acid-fractured well in a gas condensate reservoir.  These include a couple of correlations for the estimation of fracture width and half-length. Then it will be shown how these dimensions can be used to estimate fracture conductivity and effective wellbore radius. In gas condensate reservoirs, because of condensate buildup around the fracture and also different velocity effects, fracture conductivity might be very different. These effects are discussed in the paper and the required correlation for estimation of effective wellbore radius in gas condensate reservoirs is presented. The correlation includes inertial and coupling effects as well as the influences of two-phase formation in the matrix and fracture. The introduced correlations can be very practical in the estimation of well productivity and also in reservoir modeling.

Water flooding is one of the common secondary recovery methods. One of the major problems of water flooding is the production of water. Consequently, water breakthrough happens quickly. In these conditions, the production of the reservoir is not economical. In comparison to conventional flooding, cyclic water flooding (CWF) produces more oil and less water. CWF is performed to produce oil from a zone with less permeability that cannot be displaced. Studies have shown that oil production is more likely to occur during the period of injector shut-in. To achieve maximum oil production from oil fields and less produced water, optimization methods should be used in the process of cyclic water injection. By controlling and optimizing the well parameters, such as production and injection rates, as well as the economic evaluation of the process, one can achieve this goal. The purpose of this study is the scheduling and optimization of production using net present value (NPV) for this process. In this research, two-dimensional and three-dimensional models from reliable literature data are simulated. After validation and comparison to the literature, the sensitivity of the model for the duration of injection and shut-in of the injector is performed in CWF. To optimize, we used the genetic algorithm, which is an efficient stochastic approach without the requirement of derivative calculation. The results showed that the CWF in a two-dimensional model in water-wet and oil-wet reservoirs has increased in NPV value of 2.26% and 3.9% respectively. In 3D model, the results showed NPV value in the cyclic flooding method in comparison to conventional flooding in the oil-wet reservoir has increased 3.285% and, in the water-wet reservoirs decreased 3.038%. The result of this study suggests CWF as a suitable secondary recovery approach in comparison to conventional flooding, especially oil-wet reservoirs.

Formation water is an important sample of electrolytic solutions. The amount of salts dissolved in water formation affects the volumetric properties of the formation water. In waterflooding, seawater, an electrolytic solution with very low concentrations of salt, forms an electrolytic solution with a high salt dissolved water (formation water), and therefore its properties change. The precise estimation of water formation properties plays an important role in estimating the flooding process. In this study, electrolyte PC-SAFT, in conjunction with Debye-Huckel's theory, was used to model the density and equilibrium of vapor and electrolytic solutions. In this equation, the state of ions is considered independent of the salt-forming it, and each ion needs two parameters of ionic diameter and extra dispersion energy over the usual PC-SAFT parameters. In this study, for the verification of the implementation of this equation, the vapor pressure, and the density of the solutions of sodium chloride, potassium chloride, sodium bromide, sodium sulfate, and lithium sulfate, as well as the vapor pressure of sodium chloride, potassium bromide, sodium bromide, and potassium chloride mixtures was compared with experimental data. Finally, using the validated program, changes in the formation water phase behavior is investigated by combining injectable water and the vapor pressure and molecular volume of their composition are predicted. Using this method, the properties’ changes of formation water are investigated by combining them with sea water in different proportions.

In many reservoirs, due to the inappropriate mobility ratio between oil and displacing fluid, the oil recovery factor has no significant increase even after using emerging low salinity water flooding. Polymer solution injection to achieve further oil recovery is limited by water salinity. In this paper, the synergy of low-salinity water flooding and polymer injection is investigated as a potential EOR in an Iranian oil reservoir through coupling fluid flow and geochemical modeling. In order to model change in wettability, the interpolation factor of relative permeability and capillary pressure was obtained using geochemical reactions between rock and low-salinity water. Different scenarios were designed to investigate the effect of water salinity during continuous waterflooding, water flooding before and after polymer injection with different concentrations of polymer, and the effect of the salinity of polymer solution on oil recovery in the reservoir. During low salinity water flooding oil recovery increases by 4.19% in comparison with high salinity water. When low-salinity water is injected before high-salinity polymer, oil recovery increases by less than 1% compared to the high salinity. Low salinity of the chemical solution leads to an increase in the oil recovery performance of polymer flooding due to an increase in solution viscosity. Considering formation breakdown pressure, a low salinity polymer solution with a polymer concentration of 100 ppm is appropriate from an operational viewpoint. Oil recovery increases by 5.05% in comparison with high salinity  polymer. Low salinity water after polymer injection is more effective than high salinity water during tertiary recovery. During low salinity polymer injection with the concentration of 100 ppm followed by low salinity water in the tertiary stage, an increase in oil recovery is 2.27% in comparison with continuous low salinity water flooding. Combined low salinity water and polymer injection in the reservoir can be considered as one of the selected EOR methods to perform on a pilot scale.

Determination of wax appearance temperature is a crucial specification in the transportation and storage of crude oil or heavy refinery products same as fuel oils. In this work, to determine wax appearance temperature different applicable methods were tested and developed. At first, the microscopic experiments were applied to different samples. Then the variation of viscosity versus temperature was monitored. To determine a feasible method to be applied in the fields, the variation of viscosity versus temperature was monitored. It was declared that at the wax appearance temperature a deep change in viscosity happened. Eventually, the wax appearance temperature of different crude oil including Iranian or heavy crude oil can be determined by the viscosimetry method. In the related experiments, the negative effect of water sediments and wax crystals was eliminated. It was also declared that the wax appearance temperature could be varied by variation of density, wax content, pour point, and asphaltenes of the samples. To correlate between input and output variables three different modeling methods were tested and implemented. The Artificial neural networks, Neuro-fuzzy, and regression models were tested to derive the most accurate correlation. The statistical studies approved that the regression models have suitable accuracy. The results of the regression model declared that the interaction effect of density and pour point and the effect of asphaltenes as one of the main input variables have the greatest impact on the wax appearance temperature.

The use of chemical surfactants such as sodium lauryl sulfate in detergents can cause various problems such as skin and eye irritation, nervous system disorders and cancer. Therefore, the use of biosurfactants due to their low toxicity and biodegradability has received much attention. In this study, the production of a green shampoo sample using rhamnolipid biosurfactant was investigated. First rhamnolipid bio-surfactant was produced from Pseudomonas arginosa PTCC 1340 with using of soybean oil as a carbon source in a laboratory scale of about 1.4 g/L and proved by thin-layer chromatography (TLC) analysis and Fourier transform infrared spectroscopy (FTIR). The results of the retardation factors in TLC paper showed that a rhamnolipid mixture (type 1 and 3) was produced. The appearance, chemical and microbial properties of green shampoos were investigated by replacing produced rhamnolipids with sodium lauryl sulfate. By comparing the results with standard reference values, it was found that the properties of the green shampoo samples were in the standard range based on the formulation presented in this study. These results can be a step toward improving the quality of lifestyle of people's life in the community.

The production of renewable fuels and the gradual replacement of fossil fuels have been one of the main challenges of researchers in recent decades. Biodiesel is one of the fuels that is used by various sources and used in diesel engines. The production of biodiesel from third-generation sources has faced many challenges, especially in recent years. In this research, biodiesel was produced from microalgae oil in two wet and dry methods of native Dunaliella Sp. of Iran, and its properties were studied. The results showed that the wet method (direct method) has a higher yield than the dry method because the biodiesel is produced directly from moist biomass. So that the maximum extraction efficiency of the oil in the wet method was 17.4% and in the dry method it was 10.2%. The best extraction yield was achieved at 60 ◦C and 30 minutes. The duration of oil extraction in the wet method due to the removal of the drying and desalting steps is considerably shorter than in the dry method. Therefore, the wet method has a high potential for biodiesel production. The microalgae Dunaliella SP. the fatty acid profile has 14 to 20 carbons and the main portion is composed of Palmitic acid (36.62%) and Stearic acid.