نشریه شیمی و مهندسی شیمی ایران
سال چهل و یکم شماره 4 (پیاپی 106، زمستان 1401)

In this study, solid zeolosulfuric acid (SO3H@zeolite-Y) was first obtained by the reaction of zeolite-NaY with chlorosulfonic acid. Ca2+ ions were then stabilized on the surface of zeolosulfuric acid by metal exchange method (Ca/SO3H@zeolite-Y). The structure and morphology of this new bi-functionalized nanoporous was investigated and identified usingFT-IR, FESEM, EDX and BET instrumental analyses. In the following, its catalytic activity in the synthesis of benzimidazo[2,1-a]pyrimido[5,4-d]pyrimidines through the four-component reaction of 2-amino benzimidazole, cyanoacetamide and two moles of different aromatic aldehydes under green conditions was considered. One of the obvious advantages of this nanocatalyst is the presence of Lewis (Ca2+) and Brunsted acid (-SO3H) sites on a nanoporous solid substrate, which can be very useful and important in multi-component syntheses. Simplicity of the procedure, the ability to recycle the catalyst and easy separation of the product, high yield and mild conditions are other advantages of this method.

Poly(1-vinylimidazole)-Ag, P(VI)-Ag, and quaternized poly(1-vinylimidazole)-ag, Q-p(VI)-Ag heterogeneous catalyst systems comprised of Ag nanoparticles embedded within p(VI) and quaternized p(VI) hydrogel matrices has been described for the selective aerobic oxidation of alcohols and reduction of nitro phenols. P(VI)-Ag and Q-p(VI)-Ag nanocomposite was characterized by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic absorption spectroscopy (AA). Catalytic activity of p(VI)-Ag and Q-p(VI)-Ag catalysts was investigated by emphasizing the effect of different parameters such as temperature, catalyst amount, substituent effect, etc. The catalyst was easily recovered from the reaction medium and it could be re-used for other three runs without significant loss of activity

In the present study, Ni-P-GO nanocomposite coating with different pH values of path was applied on the AZ31D alloy by electroless. After coating, heat treatment was performed at 400°C for 1 h. The results of microstructural investigations by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) showed that the coating with semi-amorphous structure and cauliflower morphology was formed on the surface of the substrate. According to the EDS results, with the increase in the pH of the electroless bath, the amount of phosphorus coating and absorption of graphene oxide (GO) nanosheets increased. After the heat treatment, maintaining the morphology and growth of colonies, the coating was completely crystallized and nickel phosphide compounds such as Ni2P, Ni3P and Ni5P3 were formed, which increased the hardness. The microhardness test results showed that the hardness and toughness of the coating decreases with the increase of phosphorus. By heat treatment, the maximum hardness reached 1151 H.v. and the toughness decreased to 2.3 (MPa/√m). The results of the polarization test showed that the coating leads to an increase in the corrosion resistance of the substrate and a decrease in the corrosion density up to 0.443 µA/cm². Although heat treatment led to a decrease in corrosion resistance compared to before. Also, increasing the phosphorus of matrix to increase the density of the hypophosphite layer and absorb more GO leads to an increase in corrosion resistance.

In this paper, the structural, electronic and pressure characteristics of GaP composition in different phases have been investigated. The calculations are performed using the pseudopotential method, in the framework of density functional theory, and  PWscf code. The pseudopotentials applied here are generated using norm-conserving condition within LDA and GGA for exchange correlation functional. The results of the compressibility indicate that as the pressure increased from Zincblend to Cmcm phase the hardness of compound is increased. Investigation of Energy –Volume curves shows that the cinnabar phase is metastable. The study of the band structures suggests that this compound is a semiconductor in Zincblend and Cinnabar phase with indirect band gap and is a metal in Cmcm phase.  The electron density also indicates the covalent bond between the Ga and P atoms.

In this research, first, functionalized Fe oxide magnetic nanoparticles based on sulfonated tris(hydroxymethyl)aminomethane/copper (II) nitrate were synthesized as a new, effective and recyclable magnetic catalyst, and then, was used in the reaction of preparing of Various 2-pyrazolines. Finally, the  prepared 2-pyrazolines were  oxidized to  the corresponding 2-pyrazoles under in situ and one-pot conditions, in such a way that, under optimal conditions, a wide and different range of unsaturated α, β-unsaturated  ketones (trans-chalcones) that had various functional groups including electron-donating and electron-withdrawing groups, were successfully transformed into the corresponding final products under easy and mild conditions. All products were obtained in good to excellent yields and no by-product was observed. The new synthesized magnetic nanocatalyst was characterized by various methods including infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray (EDAX), X-ray diffraction (XRD), elemental analysis (CHN) and analysis Thermogravimetry (TGA). The catalyst was easily recycled by the external magnetic field and was used for several times without observing a significant and effective decrease in its catalytic activity. Also, the structure of various synthesized 2-pyrazoles were confirmed by comparing their physical characteristics including melting point with the reported samples and also by infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectrum (1H-NMR), carbon nuclear magnetic resonance spectrum (13C-NMR) and elemental analysis. Finally, no using of harsh reaction conditions, the no by-product formation, as well as the ability to recycle and reuse the catalyst, made this method an environmentally friendly method.

In this research work, various derivatives of the heterocyclic system, imidazo [4,5-a] acridines, which have a suitable history of biological activities, were prepared using the reaction of alkylated benzoimidazole compounds with different aryl acetonitrile in high yields. After purifying and proving their structure, their interaction with urease enzyme was investigated experimentally. The experimental results of their IC50 investigation show that these compounds have a very good inhibitory ability against urease enzyme compared to the thiourea standard. Also, in order to more closely examine the interaction sites in the desired ligands and urease enzyme, simulation and molecular docking methods were used. Studies show that the chlorine derivative has the most interaction with urease. The examination and comparison of experimental and calculation results shows that these studies are very suitable and close to each other.

In this work, the effect of zeolite catalyst on the pyrolysis process of polyethylene terephthalate and poplar wood was investigated. For this aim, 15 grams of sample was loaded in a laboratory-sized reactor and pyrolyzed at 500°C under atmospheric pressure. The results showed that zeolite catalyst can change the characteristics of manufactured products. In the case of gaseous products, the catalyst reduced the amount of carbon monoxide and carbon dioxide. The results of the liquid product analysis showed that light aromatics such as benzene and xylene and light linear compounds such as alkanes including octane, hexadecane and heptane, etc. Liquid was available. By adding the zeolite catalyst to the reaction medium, the amounts of the mentioned compounds changed significantly. For example, the amount of alkanes decreased. The results of the analyzes showed that the catalyst had almost no effect on wax formation. Analysis of poplar wood, polyethylene terephthalate and char samples produced in thermal and catalytic pyrolysis showed that the two samples had similar properties, but the difference in intensity in the characteristics of different bands showed different numbers of chemical operating groups in the char samples. Analysis of the catalysts showed that due to the small increase in carbon content, it can be concluded that a very small amount of coke sat on the catalyst.

In this study, pyrolysis of polyethylene terephthalate in the presence of helium, nitrogen and argon carrier gases in the presence/absence of zeolite 4A catalyst was investigated. Feedstock was PET Bottle Grade granules and 15 g of that was used in a semi-batch reactor. Experiments were conducted under atmospheric pressure at 500 °C. The results showed that the yields of gaseous and liquid products increased by the catalyst and the rate of increase were different for different carrier gases, so that the highest increase was related to argon carrier gas (12.4% for gas and 4.4% for liquid). In addition, the yields of wax and char reduced in the presence of catalysts. GC-MS results indicated that aromatic compounds were abundant in the tar, but the catalyst and further cracking transformed them into non-aromatic and linear compounds Different results were obtained by different carrier gases. The mass and polarity of the carrier gas had a significant effect on the amount and type of compounds. Due to the heavier weight of argon and lower velocity of volatiles in reactor in its presence, small amount of liquid phase and lighter compounds in it was obtained.

The purpose of this study was to synthesize the molecular imprinted polymer of folic acid for identification and rapid measurement of folic acid by fluorescence instrument.  In the synthesis of molecular imprinted polymers for increasing the strength and stability of polymer, amounts of molar ratio of functional monomer and the cross-linker should be optimum. For this purpose, the acrylamide amide, Methacrylate and folic acid were used to synthesize molecular imprinting polymer.  This material was mixed with Sol-gel solution resulting from the addition of the Tetraethyl Ortho silicate (TEOS), ethanol (EtOH), hydrochloric acid (HCl) and water. Sol-Gel polymerization causes the formation of a three-dimensional polymer network in the shortest time without the need to apply high temperature and pressure The imprinted polymer was placed within the real sample of the solution of folic acid in the DMF solvent and after the absorption of folic acid by it, the residual solution absorption was measured using fluorescence instrument. The optimum molar ratios of functional monomer and cross-linker were obtained using fluorescence instrument. SEM polymer images were evaluated before and after washing by suitable solvent and the exclusion of folic acid molecules from within the polymer network. The results showed that in the synthesis of imprinted polymers with folic acid, the optimum molar ratios of the template the functional monomer and the cross-linker were obtained 1:6:20. Using scanning electron microscope images after polymer washing, due to the exclusion of folic acid molecules from within its network, the cavities with dimensions of 140-285nm was created.

Cyanide is one of the toxins and different ways to reduce it have been studied. These include ozone oxidation methods, ultraviolet radiation degradation, alkaline chlorination, and hydrogen peroxide degradation. Each of these methods has various disadvantages and advantages, but among them, surface adsorption is an effective and efficient method. On the other hand, zeolites, which are crystalline aluminosilicate and juicy alkali and alkaline earth metals, have the ability to absorb cations and anions. To prepare a cyanide solution, it was used sodium cyanide salt based on the standard method In this work, it has been studied the adsorption of cyanide ion from aqueous solutions using zeolite nanoparticles and the factors affecting on it. In this study, the factors of the effect of the initial pH of the solution, the effect of the initial concentration of the solution, the effect of the adsorbent amount, the effect of the contact time and the effect of temperature on the surface adsorption of cyanide ions with the nano-adsorbent zeolite clinoptilolite were investigated. And after the studies, the optimal and appropriate values for each of the effective parameters pH=6, contact time 40 min, adsorbent dosage 1g/l, temperature 22°C and initial concentration of 150 mg/l. Under these optimal conditions, the highest percentage of anion cyanide uptake was obtained on the nano-adsorbent of zeolite clinoptilolite 85%. The relationship between empirical data and the equation of Langmuir, Freundlich and Tamkin equations was also investigated. The R2 values for Langmuir, Frondelich, and Temkin's alliances were 0.8337, 0.9837, and 0.99, respectively, indicating that there was a greater match between the experimental data and the Temkin temperature than the other two.

Adsorption capacity and selectivity are two major challenges that adsorption desulfurization faces. One way to overcome these challenges is to use mesoporous zeolites. In this study, the effects of mesoporosity on the adsorption desulfurization performance with NaY zeolite adsorbent were investigated. In order to optimize the parameters, the desilication operation was performed with a mixture of sodium hydroxide (NaOH) and tetrapropylammonium hydroxide (TPAOH) solution at room temperature with ratios of R=  = 0, 0.25, 0.5, 0.75. The adsorbents were characterized by XRD, BET, FE-SEM and FT-IR. The results showed that ATY (0.5)-0.25R adsorbent has the highest mesopore surface with the value of 54.03 m2/g. Meanwhile, the adsorption desulfurization performance in a batch reactor was tested using different model fuels containing the sulfur compounds thiophene and dibenzothiophene. The results showed that different ratios of NaOH/TPAOH solution play an important role in the adsorption of sulfur compounds. In addition, Cu metal ion was impregnated on the parent zeolite and ATY (0.5M)-0.25R adsorbents in order to increase the adsorption capacity. It has been shown that the adsorption capacity of the adsorbents increases with ion exchanging of Cu metal ion, so that the Cu-0.25R adsorbent has the highest adsorption capacity of the sulfur compounds thiophene and dibenzothiophene with the values ​​of 18.28 and 21.83 mg S/g, respectively. In this regard, the effect of temperature on the Cu-0.25R adsorbent on the adsorption of thiophene has been investigated. It has been shown that, the adsorption of thiophene has increased with increasing temperature and has reached its maximum at 50 ° C. Thermodynamic studies showed that the adsorption process is endothermic. The kinetic models of adsorption of sulfur compounds followed the pseudo – second – order equation. The adsorption isotherm was well matched to the Langmuir isotherm equation and its maximum adsorption capacity for thiophene and dibenzothiophene sulfur compounds was 18.38 and 23.43 mg/g, respectively.

Considering the environmental hazards of uranium, implementing a suitable and effective method to remove this chemical poisonous and radioactive heavy metal from the aqueous solutions is very important. In this study, the biosorption of uranium using the marine brown algae, Padina sp., was investigated in a continuous system. The column was a glass tube with an inside diameter of 1 cm and 20 cm in length. The effect of various operating parameters such as initial solution concentration, bed height and feed flow rate was investigated. According to the results, the breakthrough and the saturation points occurred at 1.5 and 20 hours, respectively and the amount of the absorption capacity was 372 mg/g at the operating conditions, i.e., flow rate of 5 mL/min, bed height of 8 cm and solution initial concentration of 150 mg/L. The experimental results have been fitted with the Thomas and BDST models and the models results showed good agreement with the empirical data. The parameters of Thomas model, kTH and qm were 0.00208 L/hr.mg and 449 mg/g, respectively and 0.00208 L/hr.mg and 72.42 mg/cm3 for Ka and N0, the parameters of BDST model, respectively. Sorption-desorption studies were carried out for three sequential cycles. The results indicated that Padina sp. has the ability to uptake uranium with high sorption capacity in a continuous system and has the possibility for regeneration and reuse

Relatively high viscosity of protic ionic liquids limits their industrial applications in carbon dioxide separation processes. For this purpose, the performance of equilibrium absorption of CO2 in aqueous solution of ionic liquid functionalized with amino acid glycine named monoethanolamine glycinate, [MEA][Gly], was investigated in the temperature range of 303.15-15 323 K and various equilibrium pressures. The results demonstrated that at a constant temperature of 313.15 K, by increasing the presence of water in the solution from 80 to 95 wt%, the CO2 absorption capacity enhances from 1.36 to 2.24 (mol CO2 / mol IL), which is equivalent to 64 % augmentation in CO2 loading. Besides, utilizing a quadratic equation, numerical values of CO2 loading in terms of carbon dioxide partial pressure were developed for all the studied solvent concentrations, so that the calculated results were in good agreement with the values obtained from the experiments. The measurement of the density and viscosity of [MEA][Gly] solution, in the temperature range of 15.303 to 15.323 K, illustrated that as the amount of water in the solution declines, their corresponding values increase dramatically. Applying the empirical correlations, the values of density and viscosity were estimated in terms of temperature and mole fractions. Moreover, Clausius-Clapeyron equation was employed to compute the heat of CO2 absorption into the aqueous solution of [MEA][Gly]. Finally, although [MEA][Gly] is introduced as a novel absorbent in CO2 separation processes, high concentrations of this solvent is not suitable for carbon dioxide capture and separation, mainly due to its high viscosity.

In this study, a meso-porous Fe-ZSM-5 nano-zeolite (SiO2/Al2O3=40) was synthesized from a type of coal fly ash (CFA) containing high amount of muscovite plates by hydrothermal treatment and then the physicochemical characterization of CFA and Fe-ZSM-5 was examined using various techniques. The final product (Fe-ZSM-5) was applied in the simultaneous removal of benzene (B), toluene (T) and m-xylene (X) from aqueous solutions. The effect of adsorption parameters including pH solution, amount of dosage, contact time, initial concentration of BTX and temperature versus BTX removal efficiency was assessed under batch experiments. The maximum adsorption capacity of BTX (qmax) was obtained at optimum condition of pH=7 and 90 min (qmax; B=9.16<T=9.57<X=9.9 mg/L). Kinetic and isotherm studies showed that the adsorption equilibrium data was in good agreement with pseudo-second order and Freundlich models. In addition, thermodynamic assessments illustrated that BTX adsorption onto Fe-ZSM-5 nano-zeolite was feasible, exothermic and spontaneous at lower temperature. Based on the obtained empirical results, Fe-ZSM-5 nano-zeolite can be applied as an efficient, green and cost-effective adsorbent to remove hazardous hydrocarbons from aqueous solutions.

In recent years, the development of cities and the developement of industries have resulted in the release of a wide variety of organic pollutants such as dyes into the water resources which have posed major challenges for the mankind such as the reduction of drinking water and so on. Among the most effective methods for removing pollutants and wastewater treatment that have received much attention in recent years, is the photocatalytic degradation of pollutants using TiO2 photocatalyst which matters so much due to its high ability to remove a wide range of pollutants and being low cost and environmentally friendly. However, this process suffers from major obstacles and limitations such as inactivity under the visible light, the low adsorption capacity of organic compounds on the photocatalyst surface, and so on. In this study TiO2/SiO2 photocatalyst is used in order to remove RhB as a sample pollutant under UV-A light. In order to remove an obstacle to the photocatalytic process, which is the low adsorption capacity of organic compounds on the surface, a surface modification method called fluorination was used. FTIR and N2 adsorption- desorption were used to characterize the photocatalysts. It was found that flourination replaced the surface hydroxyl groups without altering the volume and diameter of the pores and maintaining the mesoporous structure of photocatalyst, by fluoride groups, which caused the surface to be hydrophobic. This increased the adsorption capacity of RhB by photocatalysts and consequently, it improves the RhB removal process. This was proved by photocatalytic degradation tests.

In this study, montmorillonite modified by the hexadecyltrimethylammonium bromide (HDTMA-Br) was prepared by the reaction of the sodium montmorillonite with HDTMA-Br surfactant. The adsorbent structure was characterized using Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), power-spectral-density (PSD), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) techniques. Then, the efficiency of synthetized adsorbent was investigated for the removal of the chemical oxygen demand reduction (COD), biological oxygen demand (BOD), suspended solids (TSS), oil and grease and turbidity of the oilfield produced water. The exchange capasity was obtained 200 % for modified montmorillonite. The maximom of COD reduction was resulted 92.04 % at optimal conditions with the adsorbent dosage 0.3 g, pH = 7, and contact time 45 min. The advantages of this method are cheapness, safety, and reusability of the adsorbent, short time treatment, high adsorption capacity, easy separation of the adsorbent from the reaction medium.

The presence of ions in the solution causes the water to have non-ideal. On the other hand, water molecules have strong hydrogen bonds. When water and dissolved salt are in equilibrium with gas such as carbon dioxide, they form a two-phase system with complex intermolecular forces. In this study, the aim is to model the thermodynamic equilibrium of water containing sodium chloride salt and carbon dioxide gas. The thermodynamic equilibrium of this system is analyzed using the ePC-SAFT state equation. This electrolyte equation of state is a combination of the PC-SAFT state equation and Debye-Hukel theory. The presence of repulsive, scattering, and cumulative intermolecular forces is calculated by the PC-SAFT and the electrostatic forces are calculated by Debye-Hukel theory. In this study, we first implement and predict the ePC-SAFT equation of state for non-associative pure systems. Then, the phase behavior prediction for water-salt, water-carbon dioxide and water-salt-carbon dioxide systems is performed. Finally, according to empirical data from reliable sources, the regression of the binary interaction of water-carbon dioxide in the water-carbon dioxide and carbon dioxide-salt-water system was performed. The equation of state mentioned predicts the laboratory data for the desired electrolyte solution with a good accuracy that the percentages of average relative deviation from the saturated vapor pressure data without kij parameter adjustment and with kij adjustment are 21. 46, and 14.61, respectively. In this study, it was observed that the presence of ions in the solution had little effect on the binary interaction of carbon dioxide.

This study is performed to evaluate the feasibility of a direct contact membrane distillation system with a new motive force. A thermos-electric assisted direct contact membrane distillation is designed and fabricated to desalinate a wide range of saline water by PTFE and PVDF membranes. The effective permeation area for this system is considered 12 cm2. The design of experiment is performed for this system based on response surface methodology by Design Expert software. The system is experimentally examined for different operating conditions based on the experimental set to predict its behavior. The results indicate that operating time has no significant effect on permeate flux and specific energy consumption, while, membrane material, feed concentration, and mass flow ratio have the most impact, respectively. Based on the seawater concentration, PTFE and PVDF membranes fluxes are 5.8-16.3 and 50.3-141.1 kg/m2h, respectively. The maximum gained permeate flux and the minimum energy consumption for PVDF membrane are 282.6 kg/m2h and 299 kJ/kg, respectively. For all operating conditions, salt rejections for PTFE and PVDF membrane are higher than 88.1 % and 99.6 %, respectively. This specific energy consumption is gained on maximum flux and is suitable compared to other similar desalination methods.

Reverse Osmosis is one of the membrane processes used to desalinate salt water, remove natural organic compounds, certain contaminants and water softening. One of the most important problems with this type of membrane is the polarization of the concentration and deposition in them, which reduces the product flux and increases the passage of salt through the membrane and also increases the pressure drop. It is important to choose the proper type of membrane to meet the needs associated with the Reverse Osmosis separation process. In this study, Polydioxanone polymer (12%) was used to make the Reverse Osmosis membrane. Also, the phenomenon of mass transfer in the Reverse Osmosis condensation process of the mathematical model based on the separation of water-glucose solution was considered. Considering the surface structure of the membrane, the irreversible thermodynamic model of Spiegler-Kedem was selected to investigate the mass transfer inside the membrane, and the concentration polarization model was assumed to be one-dimensional flow to investigate the mass transfer outside the membrane. The current is assumed to be constant and compressible with constant properties. The results of this study show a decrease in the amount of pure water flux along the membrane due to accumulation of salts and pressure drop and increase in the width of the membrane with increasing pressure and feed concentration. The results obtained from the distribution of glucose concentration in the water show that increasing the applied pressure difference leading to increases the polarization of the concentration on the membrane surface, which should mainly reduce the product flux. But due to the membrane structure, increasing the pressure leads to an increase in the product flux.

Manipulation of microparticles by sessile droplets is important for the control of multi-step biological and industrial processes in wide range of applications e.g., in disease diagnosis, cell separation, and so on. Here, we report on the flow structure inside a sessile droplet containing a hydrophobic microparticle using many-body dissipative particle dynamics (MDPD) simulations. The droplet is actuated by a linear wettability gradient on the solid substrate to pick up, transport, and deliver a hydrophobic microparticle. For quantitative analysis, the droplet velocity at different locations was presented using a modified “quasi-stationary” post-processing method. Detailed flow structures are presented at different time sequences of high interest, such as when the droplet touches the microparticle, when the droplet starts to pick up the microparticle, when droplet transports the microparticle, and finally when droplet delivers the microparticle. Due to the existence of the microparticle, the flow structure inside the sessile droplet is significantly altered compared to the case without a presence of the microparticle inside it. More importantly, in presence of the microparticle droplet velocity follows a nonmonotonic trend. The friction between the microparticle and the substrate not only can retard the motion of the droplet, but also may cause the microparticle to be delivered. This is due to the fact that when the friction force increases, although the driving force exposed on the microparticle by the droplet is increased however its amount is limited by the cohesive attraction forces of the droplet. Hence, when the required driving force to transport the microparticle gets larger than the maximum of it provided by the droplet, the microparticle will be dropped off. More importantly, it is proved that the critical velocity for the delivery of the microparticle is mainly affected by the cohesive forces inside the droplet, not by the droplet morphology.

In recent years, smart water injection as an efficient method of oil extraction has received particular attention from different researchers. Concentration and salt type are important and influential factors in the thermodynamic equilibrium properties such as interfacial tension (IFT) and wettability. In this study, salt type performance on the physical and chemical properties of reservoir rock, changing the balance into the desired direction, and increasing oil production have been investigated in the smart water process injection. IFT and contact angle measurements and core flood test were performed to achieve the goal. Initially, rocks from the Baba Koohi outcrop in Fars province were prepared. Then, scanning electron microscopy (SEM) and X-ray fluorescence (XRF) spectroscopy were performed. The effect of NaCl, KCl, Na2SO4, and MgCl2 salts and the combination of MgCl2 / NaCl salts with the same ionic strength of 0.7 on the wettability alteration of water-wet dolomite carbonate rock has been investigated. The effect of the above salts on the IFT reduction has also been investigated. In addition, with the help of IFT and contact angle values, the spreading coefficient was calculated to select the appropriate injection salt for the core flooding tests. Finally, flooding experiments were performed with the cores with close permeability and porosity. According to the results obtained from the measured contact angle, the type of salt does not significantly affect changing the wettability of water-wet carbonate rocks. Despite the IFT reduction in the presence of salt, this effect on the spreading coefficient was insignificant. However, the injection of an aqueous solution containing MgCl2 salt resulted in the extraction of 6.1% of the original oil in place (OOIP) in the tertiary stage, which indicates the complexity of the dominant mechanism during smart water injection into the carbonate reservoirs. Besides, the results of this study show that aging time is a practical and useful parameter in oil extraction.

One of the effective methods in the process of enhanced recovery of oil reservoirs is applying the nanotechnology to alter the wettability of the reservoir rock. In this study, the wettability alteration was investigated using synthetic graphene oxide-Hexamethyldisilazane (GO-HMDS). For this purpose, XRD and FTIR analyzes were used to identify the synthesized structure. In the present study, the effect of concentration (0.05, 0.1 and 0.2 wt% GO-HMDS) were investigated using the zeta potential analysis, Interfacial Tension (IFT), and contact angle. Subsequently, the concentration of 0.2% was determined as a powerful sample in altering the wettability of the reservoir rock through the zeta potential analysis. This sample was used for tests of contact angle and interfacial tension. In addition the zeta potential of the sample was measured by -36 mv. Moreover, the contact angle between the reservoir rock and the graphene oxide- (Hexamethyldisilazane) solution for 0.2 wt.% GO-HMDS solution decreased from 161 to 44 degrees. On the other hand, it is in agreement the results of the zeta potential and Interfacial Tension (IFT) examines. Therefore, the synthesized nanofluid reduces the and Interfacial Tension (IFT), contact angle, and wettability alteration toward the water-wet of the carbonate core.

Gas recycling is a generally accepted method to improve production from condensate gas reservoirs and has been welcomed due to its low cost compared with drilling new wells. The use of the net present value, which is both a factor of time and cost, is a reliable way of evaluating this process which considers the costs of injection facilities and production costs. It is important to find new methods for planning and optimizing gas injection. In this research, it has been tried to identify the optimal amount of gas recycling as well as the amount of gas produced by combining optimizers and reservoir simulators and using evolution optimization algorithms. It is worth noting that the method used in this study is based on a case study of gas recycling. The study shows that with the recycling of the entire production gas in the studied reservoir, the net present value could be increased from $ 126 million to $ 40 million. The production and recycling of a portion of the gas in an optimal form also increases the reservoir's life due to economic constraints from 10 years to 18 years. In addition, with a closer examination, it was concluded that due to the higher price of injected gas in cold seasons compared to the warm seasons, 65 percent of the gas produced can be returned to the reservoir in these seasons. By sensitivity analysis of the optimization results, the gas prices as well as the amount of gas condensate richness have significant effects on the optimal amount of recovered gas.

Due to limited resources of fossil fuels and the increasing demand of energy at global level as well as environmental pollution, optimal management of energy resources is of particular importance and plays an important role in large-scale national policy and planning. Although a significant amount of recoverable gases by the upstream oil industry, refineries, and petrochemicals are introduced into the environment via the refining process and through the flare gas emission systems. Flare gases have a very high fuel value. Meanwhile burning these gases in the flare system and their release into the environment, has environmental damages which in many cases is not compensable and leads to the imposition of high economic costs on countries. Present investigation indicated that Iran as the second largest owner of natural gas reservoir in the world produced about 9.5 trillion cubic feet of natural gas at 2017 and about 0.6 trillion cubic feet of that amount (about 6.3% of total produced natural gas) was burned in the flare systems. In this study, different methods and solutions of flare gas recovery systems are investigated in order to back into the energy cycle. In the meantime, the choice of the most appropriate technology for flare gas purification is considered as one of the most important principles of design of flare gas recovery systems. The most common methodology for utilizing flared gas in Iran is to produce liquefied petroleum gas (LPG). Also, in order to increase the exploitation of oil reservoirs, it is possible to use the gas reinjection technology. On the other hand, the use of flare gas to generate electricity at power plants, and also the use of gas to liquid conversion technology (GTL), are other suggested solutions for the management of flare gas that are still in early stages of design and implementation phase.

Due to the critical importance of reducing environmental problems and creating added value from gas resources, refinery and petrochemical processing units have considered implementing flare gas recovery systems. In this study, the flare gas recovery unit of the Tabriz Oil Refining Company was simulated using Aspen HYSYS software and compared with a proposed model. The simulation was based on three processes: compression, separation of liquid and vapor phases, and sweetening of recovery gases. The compression process was carried out at a constant temperature as much as possible, utilizing both liquid ring and centrifuge compressors. Safety and economy were prioritized in the selection of primary and secondary equipment for the simulation. The results showed that the liquid ring compressor was safer than the centrifuge compressor in the compression process, despite the centrifugal compressor showing better performance in the separation process of liquid and steam phases. Both models performed equally well in the sweetening process of the flare gas recovery unit. This research aims to demonstrate the potential of using and comparing centrifuge compressors in cases where liquid ring compressors are inaccessible for these units.

In this study, hydrogen production was simulated and optimized using the coal gasification in the moving-bed reactor. In this reactor, coal from the top and the combination of oxidizing gas and steam from below is in contact with solid and gas produced comes out from the top of reactor. The results of the simulation have been compared with the experimental values and the average relative error of 2.47% indicated acceptable accuracy of simulation results. The effects of inlet gas temperature, reactor pressure, ratio of steam to oxygen and coal to oxygen are investigated on the hydrogen production efficiency. Although some studies have been published regarding the modeling of the moving-bed reactor in the coal gasification, limited parametric studies are available to investigate the effect of different variables on the reactor performance with Pittsburgh coal as food. Also, in this study, simulation with discrete temperature for gas and solid to determine the exact maximum temperature of the solid phase, the kinetics of all possible reactions, simultaneous use of shrinking core and volumetric models in different areas of reactor and considering the distribution of gas components in the pyrolysis stage, happened that it is useful to find out more precisely the composition of the product gas. Finally, the reactor performance for generating maximum hydrogen yield is optimized using the particle swarm optimization method. The optimization results show that there is a 24.3% increase in hydrogen production yield compared to the basic mode.

Due to the importance of hydrogen liquefaction and the low efficiency of the existing liquefaction plants, many pieces of research are done to develop a proper liquefaction concept. Utilizing innovative configurations, the use of geothermal and solar energies for absorption pre-cooling systems have been extensively investigated through various studies. In the present study, an innovative concept for hydrogen liquefaction, which utilize absorption pre-cooling supplied by wasted heat contained in gas power-plant’s exhaust flow, is developed and simulated by Aspen HYSYS V. 9. Using two separate equations of state for hydrogen and mixed refrigerant streams and realistic assumption about heat exchangers and turbo-machines have increased the accuracy, besides making it practical. The simulation results show that the developed concept has a better performance in terms of specific energy consumption and coefficient of performance compared to the other proposed concepts, so that the specific energy consumption and coefficient of performance are 4.55 and 27%, respectively. In addition, the suggested concept could be supplied directly by power-plant due to the requirement of being close to the power plant. This removes power distribution losses. Other key feature of the proposed concept, which sets it apart from the other concepts, is its capability to be used for energy storage.

The effect of operating conditions on the performance of non-catalytic laminar premixed combustion of methane to synthesis gas is investigated. To this end, the effect of feed methane to oxygen ratio on the minimum required preheat temperature, and the effects of feed methane to oxygen ratio, feed steam to methane ratio, and pressure on methane conversion and syngas selectivity are taken into account. Simultaneous interaction of mass and heat transfer phenomena and hydrodynamic with chemical kinetics are studied using a one-dimensional model. The well-known GRI 3.0 mechanism is applied to model the kinetics of methane oxidation reactions. The open-source numerical subroutine of TWOPNT is employed to solve the set of model equations. The model can well predict the relevant experimental data. The effect of pressure on reducing the required preheat temperature for a lean fuel is more than a rich one so that for feed methane to oxygen ratio of 0.25, increasing the pressure from 1 to 60 bar reduces the minimum required preheat temperature by 200 K and 800 K, respectively. The reaction mixture can ignite at room temperature of 298 K for feed methane to oxygen ratio of 0.5-0.7. Moreover, increasing the content of steam and methane in feed has similar effects on methane conversion whereas their effect on syngas selectivity is opposite. Increasing the feed steam to carbon ratio up to 4 reduces the syngas yield by 83-90 percent. Steam injection to feed is necessary for reducing the soot formation and increasing the hydrogen content. An increase in pressure continuously increases the methane conversion and reactor temperature for feed methane to oxygen ratio of 0.25 while for ratios of 2 and 2.5 there are optimum pressures of 30 and 35 bar in which these parameters reach a maximum value.

Remarkable amounts of coke microparticles are discarded along with the effluent of decoking and olefin units and their separation methods have not been studied as the environmental pollutants. In this work for the first time the appropriate flocculant was determined for the separation of coke microparticles and then, the optimized conditions of simultaneous-experimental coagulation/flocculation process were determined based on the maximum amounts of sedimentary particles. After that, using the hypothesis of extreme agglomeration, the optimal conditions were calculated based on the maximum efficiency of filtration of gravity separation of coagulated particles. A set of purposeful experiments were performed based on the response surface method and using FeSO4, Al2(SO4)3 and FeCl3 coagulants at concentrations of 10, 15 and 20 ppm and with cationic (Zetafloc 7563), natural (Besfloc K300N) and anionic (Megafloc 3045PWG) poly acrylamide flocculants at concentrations of 3, 5 and 7 ppm in solutions with pH levels of 5, 7 and 9. According to the diameter criteria of sedimentary particles (d>21μm) the uniformity/curvature coefficients were obtained for the optimal conditions of particle coagulation. The results revealed that according to the negative surface charge of coke particles the maximum number of precipitable particles is formed with a yield of 96% using iron chloride(III) coagulant (8ppm), anionic polyacrylamide flocculant (2ppm) at pH=6. Moreover, based on the uniformity/curvature coefficients the results showed the priority of iron sulfate(II) as coagulant for enhancement of filtration efficiency since the diameter distribution of coagulated coke particles maximizes the porosity of filter-cake, the operation time of filter and the volume of accumulated cake. While the type of coagulant has no effect on the gravity-based separation efficiency of coagulated coke particles. Based on the results, the optimum ratio of coagulant to flocculant concentrations were determined to be 3 and less than 3 (1.5–3) for filtration and gravity separation systems.

At the present, treatment and recycling of stone cutting industry wastewater is performed by old settling basin method and filter press method which need so much water, therefor, in this method a new method is proposed and investigated based on hydraulic centrifugal force by using a hydrocyclone. The effect of operational parameters such as pressure, concentration and type of particle samples have been studied on a hydrocyclone efficiency with a diameter of 24 mm. The experiments were designed by using Design Expert 7 software based on response surface method (RSM). Analysis of experimental data was conducted based on composite central design method (CCD). Experiments were conducted in 22 series with different conditions. In this study, stone powder particles were collected from wastewater of stone cutting plants. Two stone powders samples were achieved from Granite and Travertine stones with densities of 2720 and 2550 kg/m3 with particle sizes of less than 200 μm. Particles sizes were measured by Particles Size Analysis method and particles shape were determined by using (SEM). The results demonstrated that the separation efficiency for both of samples is proportional with pressure so that the more the input pressure, the more the separation efficiency. On the other hand, increasing the concentration causes a decrease in separation efficiency. Based on the results, the more the input pressure, the more the flow rate, however concentration in the investigated range has no significant effect on flow rate. The best separation efficiency was achieved in the pressure 2.63 bar and concentration 1.6 weight percent for Travertine sample with a value of 90.31 percent and for Granite sample in the pressure 3 bar and concentration 3 weight percent with a value of 91.45 percent.

The importance of hydrocarbons in the production of various materials, as well as the supply of most part of the world's energy in the last century and the inability to replace renewable energy due to the rapid growth of global energy demand, on the other hand, has led to the extraction of hydrocarbon reserves should not be out of the focus of researchers and experts in this industry. One of the most important methods of Enhanced Oil Recovery (EOR), especially in carbonate reservoirs, is wettability alteration of the rock using chemical flooding, which has recently been considered by many researchers and research centers. Since most of the world's reservoirs, as well as our beloved country, are made of carbonates, changing the wettability of reservoir rock from oil to water wet have a significant effect on increasing the final recovery factor of the reservoir. The present study is an overview of the latest achievements of EOR through chemical flooding in carbonate reservoirs aimed at changing the wettability towards hydrophilicity. Despite extensive research on the mechanism of chemical flooding, not all aspects of it have been clarified so far. Obviously, without a comprehensive and accurate knowledge of the mechanism of this process, it will not be possible to control and improve it.in the work at hand mechanism of chemical flooding using low salinity, surfactants, polymers, nanoparticles or Nano fluids has been reviewed and an attempt is made to investigate the interactions of surface rock minerals, ions in the injection fluid, crude oil and formation brine be reviewed.