نشریه شیمی و مهندسی شیمی ایران
سال چهل و دوم شماره 2 (پیاپی 108، تابستان 1402)

In this review paper, a systematic study on the physical adsorption of ionic liquids with different cations, investigation of molecular interactions between cations and anions of tunable ionic liquids, study of different nanostructures based on graphene, silicon, germanium and boron-nitride without defects and comparison of stability between types of nanostructures and creating defects on them (pore defects and Stone Walls) and studying the effect of changes in the absorption of ionic liquids on different nanostructures without defects and defects on physical properties such as: bond energy, interaction energy, energy gap, chemical hardness, chemical potential and absorption spectra have been performed.

Curcumin is a polyphenol that has many medicinal properties. Despite its prominent pharmacological and biological effects, its low water solubility and rapid degradation limit its therapeutic applications, Therefore, the use of solid lipid nanoparticles (SLNs) or solid lipid nanocarriers as a drug delivery system, despite some excellent properties such as small particle size, biocompatibility, chemical and physical stability and easy operation, It was considered suitable for this research. The purpose of synthesizing curcumin containing solid lipid nanoparticles was to develop a new nanocarrier system for more efficient curcumin extraction and purification from Rivand plant for the first time. In the present study, maceration was performed using two solvents (normal hexane and ethanol) to extract Rivand plant and to purify the curcumin in this extract by liquid-liquid extraction method, and microemulsion method was used to prepare solid lipid nanoparticles containing curcumin. Was obtained The Curcumin in Rivand extract and Purified curcumin respectively 39/8% and 81/7% in compared with standard curcumin, The nanoparticles produced containing curcumin showed the desired size polydispersity index and zeta potential and spherical shapes as well as optimal stability in the environment. Also, the stability of the solid lipid nanoparticles in an acidic medium was evaluated with suitable results. In addition, stability of the solid lipid nanoparticles was investigated within 9 months that after the time, the increased size of particles was about 23 nm which in comparison to previous studies is the preferable result. Then, curcumin is release from the solid lipid nanoparticles was studied. The findings show that the lipid nanocarrier system has a suitable formulation and internal stimulus mechanism for controlled drug secretion. Therefore, it can be said that an optimal and controllable lipid nanocarrier was produced for the therapeutic effects of extracted curcumin.

In this research, a simple and inexpensive colorimetric detection method for dopamine was reported using laser cutting technique on microfluidic paper-based analytical devices. The effect of various factors such as reaction time between dopamine and ferric chloride, sample volume, drying time, pH of phenanthroline solution and volume ratio of ferric chloride / dopamine were investigated and optimized. The optimal values for each of the parameters were 4 min, 1.4, 2.8 and 4.2 μl, 12 min, 7.4 and 2: 1, respectively. From subsequent analyzes using Photoshop software, LOD and LOQ were calculated 0.0171 Mµ and 0.0517 Mµ, and RSD was obtained in the range of 0.12 ٪ to 17 0.17 for n = 5, which shows the good accuracy of this method. Also in this study, the potential of the proposed method as a low cost and fast colorimetric method for dopamine determination in real samples including human blood serum was shown.

Dye-sensitized solar cells (DSSCs) have received a lot of attention nowadays. One of the most essential components of DSSC is the counter electrode, which is usually made of platinum. Since platinum is an expensive material, we suggest using the SnSe electrode. By selenizing a layer of coated tin on glass thru sputtering, we obtained SnSe and used this layer as the counter electrode in a DSSC. We also used tin oxide as photoanode in the structure of the solar cell. By changing the selenization temperature, we improved the charge transport and electrocatalytic properties of the layer and optimized the solar cell performance. We also investigated the morphological properties of the layers with FESEM images. We used CV and EIS analyzes to test the electrocatalytic and charge transport properties. Also, the current-voltage curve of the fabricated cells reveals that the cell, which is made of the synthesized layer at 450 °C with an efficiency of 4.9%, gives us the best performance.

In this research nanocomposites of Pt-Co–Polyallylamine-Graphene Nanoplates (Pt-Co/PAA/GNPs) was developed to improve the oxygen reduction reaction activity and stability of commercial Pt/C electrocatalyst. For this purpose, first graphene oxide (GO) as a support material was synthesized according to hamer and affenman method. Then graphene oxide was functionalized with Polyallylamine through cross linking. After that Pt-Co as a catalyst was dispersed on the as prepared support by a novel process polyol synthesis method assisted by microwave. Raman spectroscopy measurements confirmed the graphitic structure of the produced reduced graphene oxide nanoplates. Fourier transform infrared spectroscopy results illustrate the presence of Polyallylamine in the composite. After investigation of the structure, morphology and composition of the prepared electrodes were characterized by X-ray diffraction, Field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy. the catalytic activities of prepared electrodes for the oxygen reduction reaction were evaluated through cyclic voltammetry and linear sweep voltammetry measurements in the oxygen reduction reaction. X-ray diffraction results showed that Pt-Co particles were dispersed on the support with mean particle size of about 11. FESEM images showed that the nanosized Pt- Co were successfully dispersed on functionalized graphene oxide nanoplates. The nanoparticles in the film were observed to be uniform spherical objects and well distributed. According to the electrochemical measurements, active electrochemical surface area of 15.42 m2Pt/mgPt with 62% catalyst utilization and the specific and mass activity peak currents as high as of 26.3345 and 1.7078 mA/mgPt was found for Pt-Co/PAA/GNP which is comparable with respect to the Pt/PAA/GNP electrode and commercial one.

In the present research work, multi-walled carbon nanotubes-metal nanoparticles (M-MWCNT; M = Cu, Mn) nanohybrids were prepared by chemical reduction method and the resulting nanohybrids were used for modification of carbon paste electrode (CPE) including 1-butyl 3-methyl-imidazolium hexafluorophosphate as an ionic liquid (IL). For this purpose, functionalized MWCNT and metallic precursors were chemically reduced by hydrazine monohydrate. Morphology and size of the particles were investigated by FE-SEM. FE-SEM studies showed the formation of Cu and Mn nanoparticles with average sizes of approximately 65 and 90 nm onto MWCNT surface, respectively. Elemental mapping of the prepared nanohybrids demonstrated relatively uniform dispersion of Cu and Mn nanoparticles onto the MWCNT surface. By XRD, the crystalline structure of copper and manganase nanoparticles in nanohybrides was identified. The capability of the CPEs including IL and resulting nanohybrides for electrocatalytic oxidation of acetaminophen was studied in 0.1 M phosphate buffer solution (pH=7.0). The obtained results showed the good electrocatalytic activity of modified electrodes towards acetaminophen oxidation. Also, M-MWCNT/IL/CPE nanohybrid in addition of high surface area, due to the synergistic effect, showed higher electrocatalytic activity towards acetaminophen oxidation that those other electrodes used in this research. Detection limits for Cu-MWCNT/IL/CPE were obtained 6.7 and 0.35 μM by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. Also, for Mn-MWCNT/IL/CPE, detection limits were calculated 4.6 and 0.2 μM by CV and DPVmethods, respectively.

In this study, BixOyClz/rGO-NiFe2O4 magnetic nanophotocatalyst was synthesized using the hybrid ultrasound-solvothermal method. To compare the BixOyClz/rGO and NiFe2O4 samples were also fabricated. The properties of these nanophotocatalysts were determined using various analyses such as XRD, FESEM, EDX, BET-BJH, DRS and VSM. The results obtained confirmed the correctness of the syntheses. According to the VSM analysis, the saturation magnetization of BixOyClz/rGO-NiFe2O4 nanophotocatalyst was obtained about 3.8 emu/g. Moreover, regarding the BET-BJH results, the total open pore volume and specific surface area of this sample was obtained 0.5 cm3/g and 130 m2/g. Finally, its photocatalytic performance was evaluated in the elimination of the ofloxacin and ciprofloxacin, as antibiotic contaminants, and rhodamine B and acid orange 7, as color pollutants. Results indicated the excellent activity of this nanophotocatalyst. So that, after 180 min, the elimination efficiency was gained at about 98.5, 100, 100 and 96.5% for ofloxacin, ciprofloxacin, rhodamine B and acid orange 7, respectively. These consequences were devoted the decrease of band gap and increasing the light absorption range, improving the separation and transmission of charge carriers and reducing recombination rate of them increasing the surface absorption of contaminant molecules as a result of the presence of rGO and the proper dispersion of BOC due to using of ultrasound waves and the breaking of clusters and the increment of accessible active sites.

This study includes the development of a new nanosorbent for the treatment of dye effluents. The designed and fabricated nanosorbent is comprised of a dendritic structure with symmetric primary amine active sites and a magnetic core. Employing various characterization techniques such as NMR, SEM, TEM, TGA, zeta potential, and CHN elemental analysis, the adsorption capacity of this material to remove methyl-orange dye has been investigated. The results reveal that the proposed nanosorbent offers an efficiency of approximately 68.9% with an adsorption rate of 166.2 g/min in the methyl-orange removal process. The rate constant obtained for methyl-orange adsorption on the nanodendrimer is higher than the previously reported ones, indicating a higher adsorption rate. The results of this new nanosorbent prove its high potential in adsorptive methyl-orange removal.

One method to prevent contamination of glazed building tiles by volatile organic materials is coating their surfaces with nanophotocatalyst titanium dioxide, preferably at temperatures above 1000 °C. However, at such high temperatures titanium is subjected to phase change and cannot maintain its photocatalytic properties. In other words, the conventional coating methods encounter phase change problem. The main purpose of this experimental research is to resolve the aforementioned problem to maintain the thermal stability of titanium dioxide at temperatures more than 1000C. In order to achieve this purpose, silica and duPont two-component were used. Silica-based titanium dioxide nanostructure was doped with N and Ni ions. Then the coating materials were calcined at 1250 °C. FTIR, SEM, XRD, EDX and TGA technics were used for nanostructure analysis which indicated thermal stability of the nanostructure up to 1250 °C. The main advantage of the utilized coating method is its simplicity and economically reasonability.  Titanium has a catalytic effect only in the UV region. In order to enjoy the benefits of the visible light, the nanostructure was modified with different ions. Note that, the titanium dioxide has three phases, namely anatase, rutile and brookite, among which photocatalytic properties of anatase have received more attentions. DuPont and silica together cause a delayed phase change from anatase to rutile at high temperatures. The delay is very essential for some industrial applications such as preserving self-cleaning properties of surfaces after they have been coated. The resulting environmental impact is less consumption of chemical detergents. Results indicate that for titanium dioxide the presence of the anatase phase at 700 °C is 83%, but at 800 °C anatase completely converts to rutile phase. Furthermore, catalyst modifications by duPont two-component using silica along with calcination at higher temperatures makes anatase phase to grow. So that at 1250 °C it comprises 86% of the nanostructure.

In this research, the effect of titanium oxide nanoparticles on the performance of saponin and sodium dodecyl sulfate biosurfactants in cleaning heavy crude oil storage tank was investigated. Also, after the clean up process, sodium dodecyl sulfate, saponin and titanium oxide nanoparticles were used to recover the oil from the residual sludge of crude oil storage tanks on a laboratory scale. The results showed that the optimal amount of HLB for the extraction process was about 24.1 for a mixture of 40% sodium dodecyl sulfate and 60% saponin. The results also showed that the simultaneous use of surfactants and nanoparticles leads to a synergistic effect that significantly increases the efficiency of the extraction process. The maximum residual amount of oil in the sludge under optimal conditions was about 3.6 (HLB value = 24.1 for a mixture of surfactants and 3 g / l titanium oxide nanoparticles). This value was 92.5% and 93.7% for each of the surfactants without the presence of titanium oxide nanoparticles for saponin and sodium dodecyl sulfate. The results of the present study showed that this method has the potential for industrial applications and can be used in oil recycling from petroleum sludge.

The asphaltene present in crude oil creates various challenges for its production, processing, and transportation, with the most important ones being wellbore and pipeline fouling, deactivation, and poisoning of catalysts. In this study, the adsorption of asphaltene extracted from a crude oil sample on five iron oxide nanoparticles synthesized by the Pechini method, in the presence and absence of propylene oxide and polyethylene glycol as common agents used in the sol-gel method for gel formation, was investigated. Solutions with different percentages of asphaltene and toluene were prepared, and a specific amount of iron nanoparticles (4 g/l) was added to the solutions. The mixtures were shaken for 15 hours at 250 rpm. The unknown concentration of the samples was determined by UV-visible analysis. The results indicated that the iron oxide synthesized without propylene oxide and polyethylene glycol, with an adsorption capacity of 37.31%, exhibited the best performance in asphaltene adsorption and was economically more viable. The adsorption results were described using Langmuir and Freundlich isotherms, and the physical properties of the nanoparticles were determined by XRD and BET analyses.

Nowadays, carbonated water injection is one of the effective methods of increasing oil extraction from crude oil reservoirs. In this method, the effect of CO2, temperature, and pressure on dynamic interfacial tension (DIFT) of crude oil/carbonated brine is significant. In this study, using a sample of acidic crude oil with a total acidity of 1.5 g/mgKOH and in the presence of sodium carbonated chloride solution and potassium carbonated chloride solution, the effects of each of the above parameters on DIFT over a wide range of temperatures (30 °C -80 °C) and pressure (500 psi-4000 psi) are examined. Besides, the adsorption time of natural surfactants in crude oil, namely asphaltene and resin on the interface, related to the carbonated aqueous solution/crude oil, was calculated using an experimental descending model (Mono-Exponential Decay). The results included The interfacial tension and adsorption time are compared with the results obtained in the absence of carbon dioxide, i.e., solutions of sodium chloride, potassium chloride, and crude oil. According to the results, with increasing pressure, despite a slight decrease in the equilibrium interfacial tension of crude oil/carbonated brine, little change was observed in the DIFT process. In carbonated solutions, the equilibrium interfacial tension (EIFT) decreases with increasing temperature due to increased molecular motion (increasing entropy). However, in general, it was observed that the presence of CO2 in the aqueous phase increased the EIFT compared to pure brine, which can be attributed to the acidic structure of crude oil and lowering the pH of the aqueous phase as well as reducing the ionization of natural surfactants.

In this paper, desulfurization of gasoline and gasoil samples by oxidation method using hydrogen peroxide as the oxidant and molybdenum and tungsten catalysts of polyoxometalate type were investigated. The effects of various operational variables such as 4 types of catalysts, 4 levels of hydrogen peroxide to sulfur mole ratio, and 4 reaction temperature levels on 4 real fuels were analyzed using the Taguchi design of experiment. The results showed that tungsten and molybdenum catalysts of polyoxometalate type on supports like KSF and K10 montmorillonite exhibited suitable performance and stability for the oxidation of real fuels. The predicted removal of sulfur compounds in the optimal conditions of the Taguchi method (PW/K10 catalyst, temperature of 75°C, oxidant to sulfur compound mole ratio of 14) for the gasoline model after the HDS process was reported to be 69.04%. Under these optimal conditions, the experiments were repeated three times for the gasoline model oil, and the average sulfur compound removal of 70.33% was reported. The ANOVA analysis indicated a coefficient of determination R2 value of 0.987 for the model.

Adsorption capacity and selectivity are two fundamental challenges in which adsorption desulphurization faces. One way to overcome this challenge is to use mesoporous zeolites. In this study, the effects of mesoporosity on the adsorption desulphurization performance with mesoporous HZSM-5 zeolite adsorbents, which have been synthesized by desilication operation in an alkaline environment using a NaOH solution at concentrations of 0.2 and 0.5 M, as well as a mixture of base solution NaOH/TPAOH (0.5 M) with molar ratios of R=TPAOH/(NaOH+TPAOH) =0, 0.2, 0.4, 0.6 at 75  for 2.5 hours were investigated and the results were compared with the parent microporous zeolite. The characteristics of synthesized adsorbents were determined by XRD, BET, FE-SEM and FT-IR analyses. The results showed that different ratios of NaOH/TPAOH solution in desilication operations play an important role in adsorbing sulfur compounds. Compared with the parent microporous zeolite, the mesoporous HZSM-5 adsorbent with concentration of 0.5 M and molar ratio of TPAOH/(NaOH+TPAOH) =0.4 ensures the formation of narrow and uniform intracrystalline mesoporosity without severely damaging the crystal structure, which resulted in the best adsorption desulphurization performance, including the highest adsorption capacity of thiophene and dibenzothiophene with values ​​of 16.6 and 6.7 mg/g, respectively. In this regard, the effect of temperature on this adsorbent on the adsorption of thiophene sulfur compound was investigated. The results showed that the adsorption of thiophene sulfur compound increases with increasing temperature and reaches a maximum of 18.4 mg/g at 65 . Thermodynamic studies showed that the adsorption process is endothermic. Kinetic models of adsorption of sulfur compounds followed the pseudo-first-order equation (R2 = 0.99).

The aim of this study was investigation the efficiency of the vanadium/Y zeolite shaped catalysts in the combined oxidative-adsorptive desulfurization of model fuel containing 1000 ppm dibenzothiophene (DBT) in a continuous fixed bed reactor. The shaping process was performed by extrusion method using 50 wt.% of boehmite as a binder. Vanadium was impregnated before shaping (VZB(50)) and after shaping (V/ZB(50)). The synthesized catalysts were characterized using different analysis. The obtained results indicated that specific surface area and pore volume of the zeolite decreased after shaping. However the use of boehmite as a binder significantly increased the meso-pore volume. The initial activity of VZB(50) catalyst in the DBT removal was higher than that of V/ZB(50) due to its higher surface area, meso-pore volume and higher acidity. But V/ZB(50) was almost stable during 5 h of reaction, because of more uniform dispersion of vanadium over the support. While vanadium of VZB(50) was leached leading to deactivation. Comparison of the efficiency of catalysts with different geometric shapes also showed the use of extrudes with non-cylindrical cross-section is a good suggestion providing more surface area per unit volume. 82% DBT removal was obtained under mild reaction conditions employed in the combined oxidative-adsorptive desulfurization.

Separation based on the adsorption of hydrogen and deuterium molecules in the binary mixtures were carried out by fifteen different zeolites at 77K and the ambient pressure using the classical Grand-Canonical Mont-Carlo simulation method. To simulate hydrogen and deuterium gases, their three-sites models were used to consider the effect of 77K as cryo-temperature. The separation factor was calculated based on the amount of adsorption of hydrogen and deuterium gases, the probability of energy distribution in the nano-cavities of zeolites and intermolecular, electrostatic, and van der Waals energies and the total energy of all systems were calculated. The results have shown that some zeolites, such as VSV, ZON, ACO and EUO, have a better ability to separate hydrogen and deuterium molecules with separation values between 1.28 and 1.46. Also, the temperature factor as a thermodynamic parameter as well as the chemistry of the nanometer cavities of zeolites and the shape variety of cavities in a zeolite can be effective on the adsorption of gases and therefore in their separation.

Dehydration of organic compounds to achieve highly pure and valuable products constitutes one of the most important chapters in the chemical industry. In the present study, mixed matrix membranes (MMMs) including poly(vinyl alcohol) and modified ZIF-8 mineral phase by cationic surfactant of CTAB, were evaluated in terms of their performance in dehydration of isopropanol in the pervaporation process. The prepared nanocrystals and membranes were characterized by Fourier-transform infrared spectroscopy, gas adsorption-desorption, Thermal gravimetric analysis, X-ray crystallography, and Field emission scanning electron microscopy. Microscopic images showed that the presence of CTAB changed the morphology of ZIF-8 nanoparticles from rhombic dodecahedral to truncated rhombic dodecahedral. The effect of unmodified ZIF-8 loading from 1 to 10 wt.% in membranes on the separation performance of isopropanol feed containing 10 wt.% water at 30 °C was investigated. Then, based on the optimal loading, the separation performance of MMM containing 5 wt.% of surfactant-modified nanoparticles was evaluated which proved success in achieving better performance in comparison with pure polymer membranes and MMM containing unmodified nanoparticles by presenting the permeation flux of 0.942 kg/m2h and separation factor of 174.

The aim of this study was to model the removal efficiency of cefixime by the Fenton method using a neural network. This model predicts experimental results well. In this model, the amount of hydrogen peroxide, iron catalyst, cefixime removal time, initial concentration of cefixime, and pH are the input parameters. The output variable is the removal percentage of cefixime. Total error squares (SSE), mean the square root of error (RMSE), adjusted coefficient of determination (), and coefficient of determination   in determining the number of optimal neurons in the middle of the performance index. According to the obtained results, the neural network model was able to predict the absorption efficiency with the sigmoid tangent transfer function in the hidden layer and the linear stimulus transfer function in the output layer. Also, the results of modeling the neural network with org-art showed that the grid with a 1-13-5 arrangement (5 neurons in the input layer, 13 neurons in the hidden layer, and 1 neuron in the output layer) had the best result in predicting the output. The correlation coefficients of all the levels of training, validation, and test 0.3 were 0.99436, 0.9993, and 0.96901, respectively. To predict the trend of changes, neural network tools have been used in MATLAB software.

Since the oil reserves are expiring or have limited amounts, new sources of energy, including biomass, need to be investigated. Cellulose is one of the main components of biomass. It is therefore necessary to examine the effects separately in order to determine its effect under different conditions on the products. Operating conditions such as temperature, heating rate, pressure, time, catalyst and etc. on the products derived from pyrolysis of cellulose. Here, the effect of A4 zeolite catalyst was investigated as one of the most common catalysts in pyrolysis of cellulose. For this purpose, in a reactor with experimental dimensions, 15 g of cellulose was loaded and the pyrolysis of samples was carried out at 500 ℃ and under atmospheric pressure. The results showed that in the presence of A4 zeolite catalyst, increased the amount of char from 9.83% to 12.25% and decreased the amount of gas from 37.05% to 33.83%. However, the amount of tar was not much changed (∼ 53%). The reduction of gas products, as well as the increase of char, indicated the polymerization of the volatile molecules produced in the catalytic pyrolysis process. The results of the analysis of the gas produced in pyrolysis showed that the resulting gas contains CO and CO2, which are made of from oxygenated compounds in cellulose. According to the results, the tar product from cellulose pyrolysis included two aromatic and aliphatic groups, which reduced the amount of alkanes if the A4 zeolite catalyst was not used. Based on the analysis results of char samples, deoxygenation and polymerization occurred more in the presence of catalyst. Based on the results of the catalyst analysis, some coke was formed on the catalyst.

In this work, the effect of zeolite catalyst on the pyrolysis process of waste tyre 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 could 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 the presence of light aromatics such as ethyl benzene and light linear compounds such as alkanes including octane, hexane, etc in the liquid product. By adding the zeolite catalyst to the reaction environment, the amounts of the mentioned compounds changed significantly. For example, the amount of alkanes decreased. The results of the analysis showed that the catalyst had almost no effect on wax properties. Analysis of poplar wood, waste tyre and char samples produced in thermal and catalytic pyrolysis indicated that the two samples had similar properties, but the difference in intensity in the characteristics of different bands showed different numbers of chemical functional groups in the char samples. The small amount of carbon on the surface of catalyst showed that very small amount of coke was formed on the surface of the catalyst.

Among the compounds widely used in the petrochemical industry, we can name olefins and paraffins, which are used according to their carbon content. Separation of ethane from ethylene as an important industrial product for obtaining pure ethylene is of great importance in industry. In this study, calculation and Experimental Research of molecular diffusion coefficient of ethane gas in normal methyl pyrrolidone (NMP) solvent was performed using pressure decay data in a specified time of 12 hours and Sheikhaʹs graphical method. Using the obtained molecular diffusion coefficients, the effect of temperature and pressure on the system was investigated. Also, to confirm the findings, Wilk-Chang relationship, Diaz and statistical analysis were used. According to the observations and diagrams, it can be concluded that with increasing temperature and pressure, the molecular diffusion coefficient of ethane gas in NMP solvent increases. It was also observed that the molecular diffusion coefficient of ethane gas at low pressures did not change much with increasing temperature, but with increasing pressure, increasing temperature shows its effect on the molecular diffusion coefficient. The molecular diffusion coefficients calculated by the Wilk-Chang equation do not have an acceptable overlap with the Sheikha equation, while in the Diaz experimental equation the molecular diffusion coefficients show a very good overlap with the Sheikha equation. The results of statistical analysis showed that although with increasing temperature and pressure, the molecular diffusion coefficient of ethane gas in the solvent increases, but the effect of increasing pressure on the gas diffusion in the solvent is greater than the effect of temperature. The effect of temperature and pressure interaction on the molecular diffusion coefficient of ethane gas, although small, is present and affects the gas diffusion in the solvent.

Flow patterns of six liquid-liquid systems, including chloroform/butyl acetate/ethyl acetate/kerosene/butanol/octanol-water, in a numbered-up microfluidic set-up were studied in this work. Three distinct flow regimes were observed in the parallelized microfluidic device: slug flow, droplet flow and parallel flow. A uniform flow distribution with non-uniformity less than 10% indicates the high quality of microchannels and successful numbering-up procedure in the scaled-out microfluidic device. By flow pattern analysis, a parallel flow regime with complete phase separation was chosen as the desired flow regime for calcium ion separation. Chloroform-water system and DCH18C6 crown ether were identified to obtain the maximum extraction efficiency of calcium. In these conditions, the effects of crown ether concentration ([CE]), the concentration of calcium ion ([Ca2+]) and pH were studied in order to optimize the extraction efficiency using the Box-Behnken method. The extraction efficiency of more than 60% was achieved in three sequential microchips under optimized conditions within only 3.5 seconds. An excellent improvement was also observed in calcium separation efficiency using EMIM NTf2/n-butyl acetate mixture as the organic phase. Therefore, more than 95 % extraction efficiency was achieved within 1.6 seconds using ionic liquid–cosolvent mixtures utilizing a microfluidic cascade.

In this report, mixed matrix membranes which are supported by polyethersulfone and sulfonated polyethersulfone prepared for dehydration of isopropanol. The prepared membranes are composed of a porous sublayer from polyethersulfone/sulfonated polyethersulfone and a composite top layer of poly(vinyl alcohol) and titanate nanotubes. In fact, hydrothermally-synthesized titanate nanotubes are dispersed in poly(vinyl alcohol). Moreover, the sulfonated polyethersulfone are used to investigate the effects of the porous sublayer on mass transport and the separation performance of the membranes. Next, the ability of the prepared membranes were studied for pervaporation separation of 90 wt% aqueous isopropanol mixture at 50 . The obtained results indicate that the thickness and chemical properties of the support have had a significant influence on pervaporation results. Totally, decreasing the difference between hydrophilicity of top layer and support has resulted in formation of an ideal interface between the layers. Furthermore, the presence of sulfone groups in interface, formation of hydrogen bounds among hydroxyl groups of poly(vinyl alcohol) and sulfone groups of the sublayer are responsible for enhanced compatibility between the layers. As a result, selective separation of water through the membranes was obtained. In addition, the results indicated that the support led to existence of an additional mass transport in isopropanol dehydration as well as requiring the physical support for the resultant membranes. The obtained results showed that when 4 wt% titanate nanotubes were dispersed in poly(vinyl alcohol) which was supported by sulfonated polyethersulfone the flux and separation factor were about  0.29 kg/m2 h and 4828, respectively.

Plasma technology is one of the newest methods used for energy production and waste treatment. The addition of plasma technology to gasification has created a new method for waste management. However, the plasma gasification process is one of the complex thermochemical processes in which many reactions occur simultaneously, therefore it is very difficult to study the theory of this process. Therefore, having approximate and simulated results before launching and implementing the proper system of this process for biomass waste is essential in order to reduce operational costs and time. In order to study this complex process, a model based on the minimization of Gibbs free energy in Aspen Plus software environment has been developed. The created model, that is based on thermodynamic equilibrium, was evaluated with the results reported in scientific sources, which gained the necessary credibility to study important operating parameters such as temperature, equilibrium ratio and vapor ratio on syngas components. The effect of equivalence ratio on the components of the gas product was investigated and it was concluded that the parameter is very effective in the plasma gasification process, the increase of which causes the process to proceed rapidly towards combustion. The highest amount of hydrogen production for steam as a gasifying agent was obtained at a temperature of 900°C which is much more than the amount of hydrogen produced for the air. Also, the equivalence ratio showed the greatest effect on the value of the lower heating value of syngas compared to the temperature parameter. The effect of temperature was significant up to about 800°C and after this temperature, the effect decreased.

The present study aimed to experimentally investigate the heat transfer in Fe3O4 / water ferrofluid in a channel with a square cross-section, ​​0.8 m × 0.01 m × 0.01 m in dimension under the influence of uniform heat flux in a laminar flow regime in the presence of a local external magnetic field. Local Nusselt number investigated with different volume fractions (0.5 and 1 vol.%) in the presence of magnetic field and under the influence of some heat fluxes (30, 86.7, 229.95, 433.65, 573.51 Watts). The heat flux is applied evenly to all surfaces of the duct. The effect of heat flux, local magnetic field, and volume fraction of Ferro-particles on Nusselt number are investigated simultaneously and separately. Under the external local magnetic field, the Nusselt number increased 1.33 times. Under the influence of an external local magnetic field compared to pure water, the Nusselt number increased 1.36 times. These maximum values ​​occurred in 1 vol.% and the lowest applied heat flux of 30 Watts. These results show that usage of Fe3O4 particles and externally applied magnetic fields have a synergistic effect on increasing the Nusselt number.

Vanadium redox flow batteries (VRFBs) with large energy storage capability are one of the most important electrochemical technologies in the world. The specific design of these batteries has made it possible to increase the storage capacity to very high values. Hence, this technology is referred to as the electricity supplier of cities in the not too distant future. In this article, fabrication, development, and the simulation of VRFBs in order to take an important step towards achieving technical knowledge of this promising storage technology, have been considered. In this regard, first, the designed cell structure was introduced and the method of material selection and initial preparation for the battery startup were described. In addition, the governing equations of the system were presented. Then, experimental and numerical investigation of the system performance was followed by simulation validation. Evaluation and analysis of cyclic performance, system efficiency, effect of current density, electrolyte concentration, pressure distribution and electrolyte velocity distribution were among other items of interest in the present work. The model predictions were validated with an average error of 4.92% against experimental data of charge and discharge cycles at current densities of 40 and 60 mA/cm2. The results obtained from cyclic performance of the battery clearly indicate that the average coulombic efficiencies of the system at current densities of 40, 50, and 60 mA/cm2 are 90.25%, 92.45%, and 94.35%, respectively. Moreover, the storage capacity of 133 mA. h with a pressure drop of 2400 Pa were obtained for the electrolyte concentration of 1 mol/L and the volumetric flow rate of 40 mL/min, which indicates the proper hydrodynamic and kinetic performance of the designed system.

In this paper, the thermodynamic equilibrium analysis of dry reforming of methane was performed by Aspen Plus software in order to increase the selectivity of hydrogen, elimination of carbon and adjust the H2/CO ratio. Equilibrium calculations were performed using Gibbs free energy minimization method. The effect of CO2/CH4 molar ratio (0-6), pressure (0.5-20 bar) and reaction temperature (300-1100 K) on equilibrium conversion rate, products selectivity and carbon formation were evaluated. The results showed that increasing the temperature and decreasing the molar ratio of CO2 / CH4 has positive effect on the rate of hydrogen selectivity, so that at the molar ratio of less than one CO2 / CH4 and temperature range above 1000 K, the rate of hydrogen selectivity reaches 100%. In contrast, with increasing pressure at constant temperature, the rate of hydrogen selectivity decreases, indicating the negative effect of the pressure on the rate of hydrogen selectivity. Carbon is the main by-product of dry reforming of methane, which must be removed in order to optimize operating conditions. At the ratio of CO2 / CH4 =1-6, with increasing the temperature and especially in the temperature range of 300-1000K, the amount of carbon formation decreases, but with increasing pressure, the amount of carbon production has an upward trend. On the other hand, with increasing the temperature, the conversion rate of carbon dioxide first decreases and then, with further increase in temperature, increases. In addition, the adjustment of H2/CO ratio of the syngas was performed for using in various processes, which can be achieved to the desired value by changing the CO2/CH4 ratio and pressure.

The adequate understanding of sustained combustion and performance control in liquid propulsion engines requires sufficient knowledge about combustion chamber conditions, a series of chemical reactions that occur in the combustion chamber, and the thermo-physical variables based on the chemical reactions. For this purpose, after studying the governing equations and simulating the combustion chamber in different equivalence ratios, the distribution of temperature, chemical reaction rate, and mass fraction of chemical species are presented as the foundation for the challenges of the combustion chamber and related systems design. The simulation results desirably predict and justify many properties related to hydrogen-oxygen and methane-oxygen propellants. For methane-oxygen propellant due to the production of carbon monoxide at high ratios of fuel to oxidizer, a decrease in specific impulse, temperature, and chemical reaction rate of propellant is observed in the combustion chamber. The maximum temperature in the combustion chamber and the areas near the injectors for this propellant is much higher than the hydrogen-oxygen propellant at the equivalence ratio equal to one. Higher temperatures can cause serious harm to the combustion chamber wall, propellant transmission system, and injectors. Improving the nozzle design can also convert the thermal energy of the combustion gases into kinetic energy and velocity and can increase the specific impulse.

The purpose of this article is to design a biological reactor or fermenter equipped with image processing technology in real time with the possibility investigating the volume and number of bubbles in the bioreactor container  that allows instant and precise control for the growth of microorganisms. In the aforementioned biological reactor, optimal conditions are provided for the growth of microorganisms such as fungi, bacteria, and yeast, and the cultivation of animal and plant cells is easily done in it. The use of this bioreactor allows microorganisms to grow for more than ten generations before being transferred to the production stage. In addition to controlling the volume of air bubbles, the parameters of temperature, CO2, engine speed, amount of oxygen and pH and other parameters are constantly being controlled. In biological reactors, measuring the bubbles created in the container is very important. This importance can be seen from the fact that it causes the creation of various generations of cells in the biological reactor, because the created bubbles are responsible for delivering oxygen to the existing microorganisms, as well as stirring the environment and homogenizing it. In the previous models, it was not possible to measure the amount of air in the container and control the homogeneity of the environment now, and this weakness is overcome with the help of this method. In this article, in the first step, with the help of the camera, moment-by-moment images are recorded as input data, in the second step, the images are processed, and in the last step, the processed images are created with the help of neural networks as output. The volume and amount and dispersion ratio of the bubbles in the container and the simulation results show the efficiency of the proposed method.