نشریه شیمی و مهندسی شیمی ایران
سال چهل و یکم شماره 3 (پیاپی 105، پاییز 1401)

In this study, a specific sequence of oligonucleotides was attached to silver nanoparticles after thiolization in a saline medium. Investigation of this bond was performed using ultraviolet-visible spectroscopy (UV_Vis spectroscopy) by changing the silver nanoparticles' wavelength and thiol oligonucleotide attached to silver nanoparticles. Also, by bond transfer in polyacrylamide gel electrophoresis (PAGE) due to the increase in molecular weight after binding silver nanoparticles to a thiolated oligonucleotide, this bond's accuracy has been investigated. To find the bonds' electronic structure and stability, DFT studies have been performed using the Gaussian 09 program, aiming to see the optimal conditions for the binding of thiolated oligonucleotides to silver nanoparticles. In general, the binding of silver nanoparticles to thiolated oligonucleotides makes the specific adsorption of the sequence to the cell more targeted. Also, it increases the accuracy, precision, and specificity of adsorption. Calculations showed the absorption energy of -54.4 kJ / mol, the transfer of electric charge of 0.129 e after binding the thiolated oligonucleotide to silver nanoparticles, indicating a useful connection between them.

Phytosome technique is a new method for encapsulating natural compounds to increase bioavailability and absorption in the biological environment. Phytosome provides maximum adsorption conditions in target cells due to the use of phospholipids as coatings. This project aims to present a suitable method for encapsulating the polyphenolic enrich extract of Satureja khuzistanica in the phytosome structure by thin-film hydration following ultrasonication and freeze-drying. Phytosome structures were analyzed by particle size, morphology, and time-release mechanism. The results showed the phytosome particle size in the dimensions of 82.2 nm was stable for six months. The release of phytomose structure properly adjusted on Korsmeyer mechanism and release drug transport occurs by diffusion following Fick law (case-I transport).

In this paper, the mechanical properties, thermal conductivity, and thermal stability of graphene oxide/octa(aminophenyl) polyhedral oligomeric silsesquioxane hybrid aerogels with high porosity, high surface area, and ultra-low density were investigated. The combination of properties such as high surface area and porosity, and extremely low density and thermal conductivity have made these aerogels as a great candidate in a wide range of applications including energy storage and conversion devices (like supercapacitors, electrode materials etc.), contaminant absorbers, and thermal insulation. The mechanical properties and thermal stability of the prepared aerogels showed a significant improvement compared to the reported graphene aerogels. Investigation of the thermal conductivity results of the obtained aerogels showed that the contribution of heat transfer through the solid phase, λs, is superior to other heat transfer mechanisms. This superiority is maintained even at higher temperatures. This is attributed to the high self-extinction coefficient of graphene aerogels, which heat transfer through radiation is effectively suppressed. Likewise, the lower average pore size of the obtained aerogels, limits the mean free path of gas molecules at high temperature and thereby reduces the contribution of gas thermal conductivity. Since these aerogels have porosity of above 99.5%, the contribution of solid phase thermal conductivity was also very low. Finally, the influence of raw material content, density and morphology on mechanical properties, thermal stability, and thermal conductivity was investigated and the structure-properties relationship of the prepared aerogels was explained.

In this paper, the possibility of using Metal-organic framework UIO-66 in the propane ODH process at low temperatures was investigated. In this process, Nickel (Ni) was used as the main catalyst with the loading of 5, 15 and 25 (wt%) on support and O2 gas as oxidant. In order to accurately examine and determine the optimal state, the experimental design during the work was assisted. The effect of three parameters such as reaction temperature, Volumetric flow rate (sccm) and Ni loading (wt%) at three levels of -1, 0 and +1 was investigated. For better dispersion of nickel catalyst on the synthesized support, the ultrasonic method was used to synthesize the catalyst. As a result, it led to the top-loading of the catalyst with the form of a monolayer on the support. The catalyst structure was evaluated using various characterization methods including XRD, BET, SEM and EDX. In this study, the synthesized Metal-organic framework UIO-66 has a surface area of 1327.42 m2/g. Ultrasonic-synthesized nickel catalysts, due to their higher specific surface area and better nickel distribution on the synthesized catalyst, 17% by weight of vanadium oxide based on UIO-66 were able to 5.98% conversion and with 55.7% selectivity of propylene at 325 oC.

In this project, based on previous findings, first the magnetic nanoparticles were coated with silicon dioxide particles by core-shell method and from reaction with 3-chloropropyl triethoxy silane and then with organic ligand thiocarbohydrazide (Fe3O4@SiO2-TCH) was functionalized. The Cu ions were then stabilized on magnetic silicate surface. The structure of the prepared nanoparticles as a magnetic organic-metal hybrid was investigated and confirmed using FT-IR, FESEM, EDX, XRD, TGA, VSM and BET instrumental methods. Next, its catalytic activity in the synthesis of a number of 4-aryl-2-amino chromenes was investigated by the three-component condensational reaction of aldehydes, malononitrile and dimedone. The advantages of this method include cheap, safe and reusability of nanocatalyst, easy separation of heterogeneous catalyst from the reaction medium, short reaction time, high efficiency, easy and fast separation of the product and use of non-toxic water solvent, which makes this method in simplicity, be in the scope of "green chemistry".

Sandwich polyoxometalate of [(FeW9O34)2FeIII4(H2O)2]10- (Fe2W18Fe4) was placed into the gallery of Tris(hydroxymethyl)aminomethane modified layered double hydroxide, Tirs-LDH by a simple one-step process based on the anion-exchange method. The structure of Tris-LDH-Fe2W18Fe4 nanocomposite was characterized and studied by FT-IR, XRD, SEM, EDAX and zeta potential analyses. The results confirmed the successful preparation of the nanocomposite. The catalytic activity of the nanocomposite was investigated in the degradation synthetic dyes of MB, MO, congo red and RB. The parameters like as H2O2 values, pH, amount of catalyst, amount of dye, concentration and as well as its catalytic selectivity were investigated. The results showed that the catalytic activity of Tirs-LDH well enhanced by the intercalation of Fe2W18Fe4. Low cost and available precursor, easy preparation, high adsorption, and fast removal of dye make this work outstanding.

In this study, the synthesis and characterization of Sr-Ce-ZnO/HAp nanocomposite in the degradation of rhodamine B under visible light was investigated. Structure of Sr-Ce-ZnO/HAp nanocomposite identified by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy diffraction (EDX) spectroscopy (visible-spectrophotometer) UV-Vis and adsorption/desorption porosimetry were confirmed by BET analysis. Evaluations showed that adopted with metal cations and the presence of hydroxyapatite reduced energy gap, increased surface area, increased adsorption and decreased electron-hole recombination. As a result, it significantly increases the photocatalytic activity of Sr-Ce-ZnO/HAp nanocomposite compared to other prepared nanoparticles. The results also showed that more than 91% of rhodamine B was removed within 90 minutes after the start of the reaction. The first-order reaction constant and the rate constant of 0.023 min-1 were obtained.

In this study, phenylhydrazine and 4-aminobenzoic acid were reacted with co-polymer (methyl methacrylate / maleic anhydride) and in the following, used as a corrosion inhibitor of low carbon steel. The chemical structure of copolymers was identified by spectroscopy of FT-IR and H-NMR, also titration and viscosity test. the amount of thermal resistance synthesized copolymers was investigated by thermal analysis of TGA, DTG and DSC. the results indicated that the thermal resistance of P (MMA-MA) / PhH and P (MMA-MA) / ABA in comparison with the (MMA-MA) has increased. In the following, via electrochemical potentiodynamic polarization tests, EDX and FE-SEM, the effectiveness and inhibition capability of copolymers in hydrochloric acid of 0.5 mol was investigated. The results showed that corrosion rate of co-polymers are (MMA-MA) <P(MMA-MA) /PhH <(P(MMA-MA)/ABA respectively.

The ring opening due to nucleophilic addition reactions of  to   have been investigated using B3LYP method. 6-31G basis set has been employed for optimization of the structures. Presence of Nickel atom leads to the increase of positive charge on carbon atoms adjacent to the oxygen atom in relative to 5- oxaporphyrin. An intermediate is initially formed by nucleophilic attack to one of the aforesaid carbon atoms which is then directly converted to the helical open-ring complex, [ (BNü)] by passing through a transition state. In the latter products the helical ligand composes a structure in which the Nickel ion is trapped between planar and tetrahedron coordination, which has been confirmed with experimental work. Even though the most positive center for the nucleophile to attack is Nickel atom in , it has been shown that such addition does not lead to a stable intermediate. A NBO analysis has been performed aiming to investigate the relative stabilities of all species involved in the process. A key point is the fact that interaction of nucleophile with Nickel atom of , decreases interaction of the porphyrin ring with Nickel, which can be translated as an effective perturbation in the complex planar structure and thus formation of an unstable species [Nü(OP)]. Another point from such analysis has determined that connection of nucleophile to oxo-carbon in , diminishes strength of C-O bond in the intermediate. Weakening of this bond becomes profound in transition state species, which then leads to the open chain helical product. These key points and all other NBO findings have been corroborated by the results obtained from molecular orbital calculations.

In this paper, nanocrystals of zeolitic imidazolate frameworks (ZIF-8) were synthesized by solvothermal synthesis method, and their modification was conducted using molybdenum (Mo) promoter. The aforementioned modifications were carried out by two methods, including loading of Mo in ZIF-8 structure and also impregnation of ZIF-8 with Mo. Adsorption isotherms of CO2 and CH4 were determined according to the pressure decay method in the temperature and pressure ranges of 298-328 K and 1-4 bar, respectively. The obtained results indicate that presence of Mo promoter causes obvious changes in structural properties of the ZIF-8 nanocrystals, such as surface area, pores volumes, as well as, adsorption properties. Moreover, CO2 adsorption of the modified nanocrystals was obtained less than that of the parent ZIF-8. On the other hand, CO2/CH4 selectivity value of the modified ZIF-8 nanocrystals by impregnation has increased by 85% compared to non-modified ZIF-8.

Recently, the acid gas reactive absorption process by solvent used in the acid refining processes, comprehensively. In this experimental study, the carbon dioxide absorption process performed by a hybrid solvent, glycerol - potassium hydroxide in a packed tower. The effect of various factors, such as potassium hydroxide concentration (0.2-0.8 molar), glycerol concentration (4-12% wt.), and gas flow (2.3 and 1.7 l/min) at 35 ° C, 10% vol.  CO2 concentrate and atmospheric pressure have been investigated. CO2 absorption percentage, overall gas phase mass transfer coefficient and volumetric molar flux have been selected as responses. The results show that increasing the concentration of glycerol and potassium hydroxide in the mentioned operating conditions can decrease the outlet CO2 concentration. Percentage of carbon dioxide absorption by this hybrid solvent at a flow rate of 1.7 l/min, 12% wt glycerol, and 0.8 M potassium hydroxide, was 94.28%. Also, the maximum overall mass transfer coefficient based on the gas phase and volumetric molar flux in the mentioned conditions, 0.96 kmol/ m3.h.kpa at 0.8 M potassium hydroxide, 12% wt of glycerol, and the gas flow 2.3 l/min was obtained 0.96 kmol/m3.h.kPa and 67.65 kmol/m3.h.

The presence of heavy metals in the environment, especially in the water create many health problems. Effective technology for the removal of heavy metals using different  methods that are attractive from an economic standpoint, the availability and high power in remove the rest of their advantages. The aim of this study is to investigate the uptake of heavy metals (Cd and Pb) by the Suaeda aegyptiaca of the aquatic environment in the area is available as an absorbent. An experimental study was performed by dried Suaeda aegyptiaca of Jiroft (south of Iran) as absorbents. Batch experiments were performed at room temperature on a synthetic sample. The effects of absorbent dose, contact time, initial concentration of heavy metals absorption isotherms were determined and discussed. The results of the Suaeda aegyptiaca plant leaves absorb more lead than cadmium but with more energy will be absorbed. Readily available plant leaves in area and inexpensive absorbent according to the results of this method can be as a practical method to remove heavy metals from industrial waste water can be used.

In this work, adsorptive separation of propane/ propylene mixture using Cu-MOF-74 metal-organic framework was studied. For this, a fixed-bed adsorption column was designed and constructed to investigate the performance of the synthesized adsorbate under continuous flow condition. Then, the adsorption and desorption of propane/ propylene mixture (25/75) at 303 K and 3 bar was experimentally measured. By using Aspen Adsorption™ software and employing experimental isotherm data of propane and propylene, the separation process in the fixed-bed adsorber was simulated. After validation of simulation results by using experimental breakthrough curves, vacuum pressure swing adsorption (VPSA) process was simulated in order to estimate the important parameters such as product purity, recovery and productivity. Obtained results show that the software could predict the experimental data with the high accuracy and capability. Moreover, by using Cu-MOF-74 it is possible to separate propylene from propane with productivity of 2.36 mol/kg.h and propylene purity up to 99.5%.

Recently, optimization methods have been extensively applied in phase equilibrium calculations. Among these methods, Particle Swarm Optimization (PSO) can be used to calculate the interaction parameters of activity coefficient models in equilibrium systems. In this study, based on the particle swarm optimization, the interaction parameters of 5  activity coefficient models (2-suffix Margules, 3-suffix Margules, Wilson, NRTL and UNIQUAC) have been calculated for 20 ternary extraction systems (water + carboxylic acids + organic solvents) including 126 tie-lines. The values of binary interaction parameters of these models along with the root mean square deviations (RMSD) are reported. The mean values of RMSD of the systems in the order of the mentioned models have been calculated 0.0294, 0.0041, 0.0114, 0.0016 and 0.0034, respectively. The results show that all models except 2-suffix Margules model have relatively good accuracy. By comparing the RMSD values in literature and the values determined by PSO for NRTL and UNIQUAC models, the RMSD values of the models improved from 0.0124 and 0.0181 to 0.0016 and 0.0034, respectively.

In this paper, the molecular diffusion coefficient is calculated by obtaining experimental data of gas diffusion in stagnant solvent and using mathematical models based on Fick's second law. The purpose of this paper is to calculate the ethylene diffusion coefficients in n-methyl pyrrolidone (NMP) solvent at initial pressures of 600, 800 and 1100 kPa and temperatures of 278.1, 298.1 and 328.1 K using two available models. Although similar to previous researches, the experimental results from both models showed that the diffusion coefficients increase with increasing temperature, the type of dependence on temperature as DAB = A.Tn has been different from the researchers' point of view. To examine, the experimental results were compared with the predictions of Wilke-Chang model, in which n = 5.65, and Diaz model, in which n =8.5. The dependence of the molecular diffusion coefficient on temperature in the two experimental models is different, and the prediction of the Diaz model had better agreement to the experimental data of this study.

In this research the separation of methane and carbon dioxide gases by using the Nano composite membrane including poly ether block amide and poly vinyl alcohol as polymers with multi wall carbon Nano tubes is investigated.  The results of many studies show that the combinations of polyether block amide have great efficiency in making the polymeric membranes for separating gas. However, efforts are doing to improve the permeability and selectivity of such membranes.  In this study made membrane was made by using the solution molding and combining the percentage of 80 to 20 for polyether block amide/poly vinyl alcohol and carbon Nano tube with the amount of 0.5,1 and 2 percent of weight is used. Morphology and structure of the membrane made by TGA, FE-SEM, XRD and FTIR were checked.  Measuring the amount of permeability of the built membranes was done by using constant pressure-variable volume method.Total results showed that with the increase of pressure up to 8 bars, the amount of permeability of carbon dioxide and methane gases increases and the maximum amount of permeability for carbon dioxide and methane gases respectively are 4w6 and 36.44 bar.  The amount of selectivity for binary gases of carbon dioxide- methane increases with the increase of the amount of nanoparticle and the maximum amount in membrane contains 2percent of carbon nanotube and 8bar pressure with the amount of 11.69.

This work deals with the modeling of dynamic viscosities of several fatty acid esters (FAEs) and biodiesels based on the friction theory (FT) along with a perturbed hard-dimer-chain equation of state (PHDC EOS). The model used three molecular parameters (ε, σ, m) and liquid density as well, all of which were estimated from the PHDC EOS. The PHDC EOS could predict the density and isothermal compressibility coefficients in 278.15-393.15 K range and pressures up to 210 MPa with the average absolute relative deviations (AARDs) of 0.52% and 4.77%, respectively. Then, the proposed FT-based model has been employed for predicting the dynamic viscosities of several FAEs and biodiesels in 293.15-393.15 K and pressures up to 200 MPa. The model predicted 892 experimental data points for dynamic viscosities of 10 FAEs and 3 biodiesels with the AARD of 1.70%.

In this paper, the thermodynamic equilibrium of the methanol steam reforming process (MSR) for hydrogen production was studied by Gibbs free energy minimization method. The effect of operating parameters such as temperature and steam/methanol ratio in feed stream (Steam/Carbon) on product distribution was evaluated. In order to investigate the amount of undesirable by-product in the equilibrium state, the side-reactions progress in the hydrogen-rich stream were analyzed in the certain operating range (temperature: 300-600 K and Steam/Carbon: 0.1-3). The optimum conditions were determined for maximizing methanol conversion, high hydrogen production yield and minimizing undesirable products such as CO and DME. In order to investigate the effect of presence of methane in the reaction medium on the hydrogen production yield and products selectivity, two separate thermodynamic analyses were performed assuming the presence or absence of methane in the product stream. In the presence of methane (case 2), the maximum hydrogen yield was about 10%. The results showed that in the absence of methane in the reaction medium, the suitable operation conditions limit for obtain the highest hydrogen yield and decrease of undesirable by-products were 450-600 K and a Steam/Carbon ratio above 1.5.

In this work, the effect of zeolite catalyst on the pyrolysis process of polyethylene terephthalate (PET) 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 amount of gas produced in the presence of catalysts increased 8 wt%, which indicates an increase in the cracking reaction rate. The amount of wax produced in the presence of catalyst has decreased 10 wt%. The amount of liquid product obtained was increased in the presence of zeolite catalysts (from 23 to 26.5wt%). zeolite increased the propane content, which indicates an increase in cracking and conversion of heavy molecules to propane. Ethane levels increased, indicating further breakdown of heavy molecules of polyethylene terephthalate and the reaction of molecules with each other and with ethane and conversion to other products such as methane. Liquid product analysis showed that zeolite catalysts tended to reduce acidic compounds, indicating a tendency to deoxygenate or convert acids to other compounds. In addition, zeolite has also converted compounds with more than one benzene ring to compounds with one ring. Therefore, zeolite catalysts simultaneously deoxygenate and molecularly breakdown heavy compounds in the liquid product.The catalyst analysis indicated the presence of a coke layer on the catalyst, which contained more aromatic and oxygenated compounds.

The use of membrane reactors to distribute one or more components through the membrane (also known as side-feeding strategy) is an efficient method for controlling reactions pathways and achieving the highest performance. In this study, an optimization of three types of membrane reactor and a conventional tri-reformer was carried out to maximize H2 yield subject to produce the proper syngas for the next common processes, including methanol, Fischer-Tropsch, and dimethyl ether (DME) direct synthesis. In this regard, a sensitivity analysis was performed to identify significant parameters affecting H2 yield in O2, CO2, and H2O membrane reactors. A comparison between these configurations under optimal conditions shows that O2 side-feeding strategy was the most favorable strategy in terms of CH4 conversion, H2 yield, and catalyst lifetime due to no formation of hot spot temperature. Also in this strategy, the H2 yield was increased by 8% and 10% compared to the conventional tri-reformer to produce suitable syngas for the methanol and DME direct synthesis processes, respectively.

In this paper, Ti3C2TX (Mxene) was produced using 40% hydrofluoric acid (HF) from a precursor of Ti3AlC2. The Ti3AlC2 Max phase was synthesized by the mechanical method and then placed in a high-temperature furnace. To this aim, titanium carbide (TiC), titanium (Ti) and aluminum (Al) with atomic ratio of 2:1:1 were used due to the low heat capacity to increase the purity of Ti3AlC2. The parameter of different hours of ball milling was studied. To investigate the effect of different milling time on Ti3AlC2, and synthesis of Ti3C2TX, field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Raman spectroscopy, were used. The results showed that changing the milling time significantly affected the synthesis quality of the Ti3AlC2 sample. After 9 h milling, the particle size was < 38 μm and in the X-ray diffraction spectrum, all the peaks of the sample were formed according to its standard pattern, and the peak (002) is located at 2𝜃 = 9.14 degrees, which is the main peak indicates the best quality of Ti3AlC2. Also, the structural and morphological analysis results showed that Ti3C2TX MXene was produced in an entirely layered structure, and due to etching, the interlayer distance increased from 0.968nm to 1.019nm. It can be expressed that due to the change of 2𝜃 = 9.14 for the Ti3AlC2 to 2𝜃 = 8.67 for the Ti3C2TX MXene was synthesized with good quality.

Polycaprolactone/Zn(II) metal-organic framework composites (PCL/x%ZIF-8, x=10, 30, 50) were prepared by the simple solvent evaporation method. To investigate the structure of the obtained compounds infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), scanning electron microscope (SEM), and EDS map analysis of zinc element were used. FT-IR spectra and XRD diffraction patterns confirmed the presence of ZIF-8 into the polymer matrix. SEM images showed the distribution of ZIF-8 nanoparticles in composite films. The as-prepared composites were more effective for adsorbing various oils (sunflower oil, olive oil, and motor oil) than the pure polymer film owing to the synergistic effect of polycaprolactone and ZIF-8 nanoparticles. The PCL/50%ZIF-8 composite exhibited the highest efficiency for motor oil adsorption (9.5 g g-1). Then, the antibacterial effect of these nanocomposites against E. coli bacteria was investigated. Furthermore, the results of antibacterial tests showed that PCL/50%ZIF-8 nanocomposite has a significant antibacterial effect against E. coli. As a result, these nanocomposites have the potential to be used in the field of removing some pollutants and thus water purification due to their strong antibacterial effect and hydrophobic properties.

Organic matter in oily sludge is a pollutant and must be removed before sludge is released into the environment. In this research, the separation of hydrocarbons from the sludge of reservoirs in Shahid Haj Qasem Soleimani Rafsanjan and Sirjan oil depots has been investigated. All possible states with equal proportions of solvents were investigated using shaker and mixer to select a combination of solvents and the desired method. The results showed that the solvents had effective extraction and the shaker method was more suitable than the mixer for the separation of hydrocarbons. Therefore, the effect of temperature and the number of extraction steps were examined for optimal samples and compared with the conventional Soxhlet method. The Shaker method showed a high separation of hydrocarbons at 55°C and 5 extraction steps. The chloroform had the highest hydrocarbon extraction (95.8%). After these experiments, dissolution effect of the extracted hydrocarbons on the quality of gasoline and gas oil of Kerman oil depot was examined. The results showed that the mixing of separated hydrocarbons had a negative effect on the quality of gasoline but key quality control tests have shown that it is possible to dissolve these hydrocarbons in gas oil.

Collection and burning of excess gas in flare are recognized as one of the tools for safety and pressure control in oil, gas and petrochemical processes. Nevertheless, these gases are usually of high thermal value and might be used as feed in other industrial plants to produce value-added products, while burning them causes greenhouse gas emissions, air and noise pollution and unpleasant odor and somehow wasting economic resources. Various methods have been proposed for the recovery and reuse of flare or associate gases: pressure increasing and well injection, LNG or CNG production, chemical products or liquid fuel production and power generation. For choosing, the right process is required to examine various parameters that in most studies only the two main factors of gas volume and distance to the market have been addressed. However, there are other important factors in the process of recovery and utilization of associated and flare gas that must be considered. In this study, hierarchical analysis of different methods of recovery and application of flare gas is classified and investigated. The results show that among these methods the process of generating power or electrical energy is more important.

Process industries are often exposed to hazardous chemicals and operating units are subject to different temperatures and pressures. Depending on different operating and environmental conditions, Accident assessment and modeling in the field of process industry safety will be of great help in understanding and dealing with the accident. Of all the process equipment, tanks have the most potential risks due to the accumulation of large volumes of chemicals. The purpose of this study is to model and assess the risk of LPG pressure vessels in different scenarios such as explosion and ignition with different weather conditions. Therefore, appropriate control strategies and safety measures can be suggested with it. Three spherical LPG tanks related to Isfahan Oil Refinery were modeled, For comprehensive modeling of scenarios, reservoir rupture in different weather conditions was investigated And its intensity was obtained. Based on the available data from previous incidents and the availability of its recurrence rate, the degree of risk was estimated. Individual and collective risk curves of rupture of these reservoirs were placed in the warning area. Finally, suggestions were made to reduce this risk.

In the current study, fabrication and characterization of a biodegradable skin patch with controlled release of sodium diclofenac was reported. Gelatin and polyvinyl alcohol were considered the main part of the patch, and nanochitosan was selected as an agent for improving physical and mechanical properties and controlling the drug release.  Furthermore, diclofenac sodium was loaded into the polymer as a pain relief agent. The total weight percent of the polymer was selected as 5%. Different samples with weight ratios of gelatin to polyvinyl alcohol of 0.1, 0.25, 0.5, 1, 1.5, 3, and 4.5 were fabricated. The sample's appearance characteristics with a ratio of 3 were the best; therefore, this sample was considered for further characterization. Then different percentages of nanochitosan were added to the polymer substrate. The tensile strength test results showed that the highest strength is obtained in the presence of 1% by weight of nanochitosan. Afterward, different amounts of drugs were added to the gelatin/polyvinyl alcohol/nanochitosan sample. The samples' different properties were examined using the tensile test, drug release test, scanning electron microscopy, swelling test, degradation test, and thermal degradation test. The results showed that good interaction between the components and the uniform distribution of nanoparticles within the samples was achieved. Measurement of drug release rate in samples over 8 hours showed that the release rate was faster at the beginning of the test; furthermore, the drug's maximum loading was 95%. This study's findings can be a preliminary step to prove the potential of gelatin/polyvinyl alcohol/nanochitosan/diclofenac sodium compound as a pain relief skin patch.

Despite considerable progress in computational methods for calculating interactions between small molecules and proteins, estimation of the geometry of protein-ligand complexes and their binding free energies remains as a challenging task in the structure-based drug design. For an accurate description of these interactions requires the inclusion of quantum mechanical contributions using an extended atomic orbital basis set. For this purpose, some semi-empirical quantum mechanical methods have been developed that are much less expensive than more accurate “ab initio” and “density functional theory” methods.Currently, the application of fast and efficient semi-empirical quantum mechanical methods for calculating electronic properties of large molecules and biological systems becomes a routine task. In this contribution, the development of these methods and their successful applications in different fields – especially in biomolecular interactions – are reviewed.

The anaerobic digestion process is associated with biogas production, so pressure will be an important parameter affecting process. How the produced biogas discharge will be affected on system type as well as operating pressure, both of which affect the anaerobic digestion process, quality and quantity of produced biogas. In this research, effect of how produced biogas discharge by the laboratory scale anaerobic digestion system on the biogas production process with an industrial approach has been investigated in three methods.  In all methods, after injecting feed into the digester, system was subjected to a relative vacuum about   -0.1 barg per feed mass unit. First method system was batch, for second and third methods with respect biogas output were considered semi batch and continues, respectively. Other operating conditions such as temperature, mixing, type and amount of feed were same for all three methods.  For feed and digested, moisture, dry and organic matter and ash were measured and elements analysis were done. Production biogas analysis was also performed to measure the average relative composition of biogas.The results of products analysis and measurements show that volume of produced biogas in the third method compared to the second and first methods increased by 9.64% and 15.53%, respectively. These characters were shown increasing of methane volume share in compare of total biogas production 2120.22% and 21.31%, respectively. The four steps in the anaerobic digestion process are performed continuously in balance with each other uniformly. The gradual release of biogas produced and low pressure of system make the process conditions uniform and susceptible to the activities of microorganisms, especially methanogenic. Therefore, the gradual discharge method of produced biogas and its low pressure due to  lack of accumulation in the digestion tank during anaerobic digestion process has best results in terms of produced biogas and  methane  volume.

This study demonstrated a new approach of odorous gas treatment in a wet scrubbing-oxidation system with in situ generation of ferrate(VI), in which gaseous H2S could be quickly absorbed by aqueous alkaline solution and rapidly oxidized by liquid ferrate(VI) generated through electrochemical synthesis in situ. Ferrate(VI) ion production in alkaline solution (NaOH) was studied and the results showed optimum temperature for producing ferrate(VI) ion in 14 molar electrolyte solution was 50°C, and increasing voltage in rang of 1 to 10 V leading to more ion production. From ferrate(VI) self-decomposition test, it was found that 80% of ferrate ion was decomposed in 100 minutes and the increase in the temperature from 23°C to 80°C result in self-decomposing of 57% of ferrate ion. In the second part of tests, in situ generated ferrate(VI) has been used to H2S removal. The effect of temperature, ferrate ion solution concentration and gas containing H2S flow rate on H2S removal efficiency was investigated and these results were found: the optimum temperature for H2S removal was 50 °C in the test conditions, at increasing of ferrate ion concentration from 0.6 to 1.65  , 98% of H2S was removed from the gas, as well as at increasing the solution by 1 , 95% of H2S was removed.