نشریه شیمی و مهندسی شیمی ایران
سال چهلم شماره 4 (پیاپی 102، زمستان 1400)

In this study, after the preparation of unsaturated polyester with various ratios of anhydride monomers, the effects of nano silicate on the polymerization, curing behavior, and mechanical properties were investigated. The unsaturated polyester resin was synthesized at various molar ratios of anhydride monomers (maleic/phthalic: 10 to 90%) and propylene glycol. Acid number measurement was used to evaluate polymerization. With an increase in the molar maleic content, the time of polymerization reaction and the acidic number increased. In the next step, the resin was cured with an accelerator and initiator, and styrene monomer. curing behavior was determined using a curing curve and gelation time measurement. The curing curve showed that by increasing the maleic anhydride monomer ratio from 10% to 90%, the curing time decreased by 77%, and the maximum thermogenic temperature increased by 24%. Increasing the maleic content from 10 to 90% resulted in tensile strength changes from 11 to 70 MPa and tensile modulus from 60 to 359 MPa. The impact strength and the heat distortion temperature increased and became plateaued at higher maleic percentages. The nanocomposites were prepared with 50 mol% maleic anhydrides, containing 2, 4, 6, and 8 wt.% of nano silicate. By increasing the amount of nanoclay, the curing time decreased and the maximum exothermic temperature increased. Mechanical properties were evaluated by using Heat Deflection Temperature (HDT), tensile properties, impact strength, and surface hardness tests. The impact strength and the heat distortion temperature also showed an upward trend with an increase in the amount of nano, even in small quantities. By adding 8% nanoclay to the matrix, the impact strength and heat deflection temperature increased by 11% and 13%.

Interaction of penicillamine anticancer drug (pen), with armchair boron nitride nanotube (BNNT) [5,5] is studied at the B3LYP/6-31G(d,p) level of theory. For all complexes, D3-correction was carried out for the treatment of intermolecular interactions exactly. Results have shown that the adsorption of Pen molecule on the studied BNNTs surface is a favorable process. Furthermore, we estimated the strengths of the intermolecular bonds of the benchmark systems by energetic, geometric, topological, and molecular orbital descriptors. Some analyses have been made to explore any changes in the binding characteristics of the drug molecule after its attachment to the nanotubes. The maximum negative values of Ead and Had are observed for Drug@BNNT 5, so, it is known as the most stable complex. Furthermore, HOMO–LUMO analysis indicated that the electron density of HOMO is localized on the Pen drug in all benchmark systems, while LUMO is situated on the BNNT. Moreover, it was found that the energy gap between HOMO and LUMO (Eg) is reduced, which emphasizes the intermolecular bond strength. As a consequence, BNNT can act as a drug delivery vehicle for the transportation of Pen as an anticancer drug within the biological systems.

Nonsteroidal anti-inflammatory drugs are the most commonly used drugs for the treatment of articular, bone, and muscle ailments. The most famous of them are acetaminophen, meloxicam, tenoxicam, promethazine andex. These drugs have approximately the same effects, though there are slight differences, which make some of them more suitable for some patients. In recent years, electrochemical methods have become more prominent due to advances in analytical fields due to their sensitivity, low cost, and relatively short analysis time compared to other methods. In this work, using computational chemistry, which generally solves chemistry problems using mathematical and theoretical principles, the structure of acetaminophen, meloxicam, tenoxicam, and promethazine drugs was optimized using Gaussian 09 software, and the solvation-free energy was calculated. Then the half-wave potential was obtained using physical chemistry relationships, it converts to a half-wave potential. Then, by using a cyclic voltammetry device, the half-wave potential of these drugs was practically obtained and compared with the theoretical values, and the antioxidant properties of these drugs were investigated. The half-wave potential for acetaminophen in the experimental method is 195 mV and in the computational method, 213 mV for meloxicam in the experimental method of 395 mV and in the computational method is 339 mV, for tenoxicam in the experimental method of 355 mV and in the computational method 305 mV, for promethazine in the experimental method 465 mV and in the computational method 423 mV. The more negative the half-wave potential, the more anti-oxidant property. Promethazine has the most antioxidant properties among the drugs studied.

In this research, the nanocomposite of perlite@CoO@reduced graphene oxide (PC-RGO) was successfully synthesized fabricated, and characterized by XRD, FT-IR, and SEM images. Diffuse Reflectance Spectroscopy (DRS) was used to find the photocatalytic ability of this nanocomposite. In addition, photocatalytic degradation of hazardous compounds (methylene blue) by the prepared nanocomposite under LED irradiation was reported. The effects of pH, contact time, dye and adsorbent concentration and temperature are all taken into consideration. The adsorption kinetics results are adjusted to best fit the pseudo-second-order model. The experimental data are analyzed by Langmuir isotherms. The best results found in the adsorption experiments were pH 11, 10 ppm methylene blue, 0.1 gr adsorbent, and 60 minutes of contact time. The results of experiments show that as-prepared nanocomposite can be applied as a low-cost, accessible photocatalyst and adsorbent for the removal of organic pollutants from water.

In this research, the adsorption of Mg (II) was studied in a batch system by using zeolite, and the influence of effective parameters on the adsorption, such as initial pH, adsorbent dosage, contact time, initial Mg (II) concentration and temperature were investigated. Also, the surface characteristics and structure of the adsorbents were respectively obtained by SEM and FT-IR. The pH experimental results showed that the maximum adsorption efficiency of Mg (II) ion occurs at pH=7. By increasing the contact time between the adsorbent and solution, adsorption efficiency was raised, and after 60 minutes, equilibrium is reached. Results showed the adsorption efficiency decreased by increasing the initial concentrations of Mg (II) in the range of 50-250 ppm in solution, and the effect of adsorbent dosage showed that adsorption efficiency increased by increasing the adsorbent dosage from 0.5g to 2.5g. In addition, the higher adsorption of Mg (II) was observed at higher temperatures, which proves the endothermic behavior of the adsorption process. Thermodynamic parameters were investigated in three temperatures 25, 35, and, 45°Ϲ. The negative value of the Gibbs free energy (ΔG˚) showed that the adsorption process was spontaneous. Positive value enthalpy (ΔH˚) indicated that the adsorption process was endothermic, and positive value entropy (ΔS˚) can be attributed to the increased randomness at the interface of the adsorbent and the solution. The experimental results for the effect of exposure time were examined for the kinetic study with three different models: Pseudo-First order, Pseudo-Second order, and Intra-Particle diffusion. Among these models, the best fit was observed for pseudo-second-order. The study for initial concentration of Mg (II) in the solution was studied by Langmuir, Freundlich, Temkin, and Dubnin-Radushkevich isotherms, and the best fit for the adsorbent was observed by Langmuir isotherm and the Langmuir maximum sorption capacity was found to be 4.77 mg/g at 45°C.

In this study, it was tried to improve separation properties in the nanofiltration membranes by introducing Fe3O4 and GO nanoparticles. The different concentrations of nanoparticles with a constant total concentration were provided. The effect of increasing these nanoparticles was investigated in terms of pure water flux, Na2SO4 rejection, and anti-fouling properties. The characterization of fabricated membranes was done by Fourier Transform InfraRed spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM) analysis. The filtration performance of membranes by the water contact angle, porosity, water content, and salt rejection was evaluated. The results revealed that by increasing Fe3O4, the pure water flux increased from 12 L/m2h in a neat membrane to 48 L/m2h in 0.375:0.125 of Fe3O4:GO nanoparticles. Also, the highest Na2SO4 rejection (61%) was observed in M4 for Fe3O4:GO=0.125:0.375. Furthermore, the best antifouling properties were observed in 0.5 wt.% iron oxide nanoparticles with FRR% of 83%.

Propylene is one of the most important building blocks in petrochemical and polymer processes. The demand for propylene is growing faster than that for ethylene; therefore the current production is not in line with the forecast market demand for olefins. In this paper, oxidative dehydrogenation has been used in order to obtain propylene from propane, and oxygen was used as the oxidant. Molybdena-containing catalysts with nominal loading 5, 10, and 15 wt% were supported on titanate Nanotubes. Also, for the sake of comparison, Degussa TiO2 P25 supported molybdena catalyst (5 wt%) was elaborated. All catalysts were prepared by incipient wetness impregnation method and were calcined at 500°C. Analysis by FT-IR, XRD, Raman, BET, TEM, and TPR was done. The results show that the main characteristics of the titanate nanotube were confirmed by FT-IR, and the presence of H2Ti5O11.H2O was confirmed by XRD technique. Moreover, no evidence of the existence of Na-O-Ti bond was observed, and an important bond for the existence of the stable phase of the titanate nanotubes, Ti-O-H, was detected by Raman spectroscopy. TEM micrographs exhibited the layered structure of the prepared sample. The phase of the titanate nanotubes supported molybdena catalysts altered during calcination, in order to do that anatase phase was observed in all the samples. However, the rutile phase was detected along with the anatase phase in Degussa TiO2 P25 and 15 wt% supported molybdena catalyst. Calcination led to BET-specific surface area loss. The crystalline phase of molybdenum oxide of higher loading shows a higher maximum reduction peak by H2-TPR profile. As compared to titanate nanotubes, in the identical molybdena loading lower specific surface area as well as inferior catalytic activity and lesser lifetime was observed for TiO2 P25 support. However, increasing molybdena loading on the titanate nanotubes led to catalytic performance deterioration. The highest yield is for MoTNT-10 with a selectivity 31% and conversion 21.4%.

The oxidative desulfurization (ODS) process is a promising complementary process to the hydrodesulfurization (HDS) to remove refractory sulfur compounds of liquid fossil fuels such as benzothiophene (BT), dibenzothiophene (DBT), and their alkyl derivatives. Vanadium oxide has different oxidation states which may result in unique catalytic properties. In this study, the γ-alumina-supported vanadium oxide catalysts were prepared by incipient wetness impregnation and used as an oxidative desulfurization catalyst. The catalyst samples were characterized by N2 adsorption-desorption, X-Ray Diffraction (XRD), Fourier-Transform InfraRed (FT-IR) spectroscopy, and Energy-Dispersive X-ray Spectroscopy (EDS). The oxidative desulfurization was conducted at 80 °C and 1.0 atmosphere with tert-butyl hydroperoxide to DBT (O/S) molar ratio of 5.0 in the presence of 0.03 g catalyst per 3.0 g of model fuel containing 500 ppmw S (as DBT). A comparison of catalysts containing 2, 3, and 6 wt.% vanadium revealed that the best catalytic activity was achieved for 6 wt.% vanadium on the γ-alumina with 100% conversion of DBT after only 5 min of the reaction. In addition, the effect of O/S mole ratio on the desulfurization efficiency was investigated and the best result was obtained at O/S=5.

Graphene Oxide (GO) 2D (two-dimensional) material, comprised of sp2 hybridized carbon atoms and has properties and applications in various fields such as medical, environmental, and other industries. The present study aims to synthesize GO using four different methods and characterize them by FT-IR, CHN, XRD, Raman, SEM, and EDS techniques. Finally, evaluated their antibacterial activities of them. For this purpose to synthesize GO, four methods of modified Marcano (KMnO4, H2SO4/H3PO4), Hummers methods (KMnO4, NaNO3, H2SO4), modified Hummers (KMnO4, H2SO4) and the Brodie method (KMnO4, H2SO4, HNO3) were compared. As well as, the antibacterial activities of all four methods were evaluated for gram-positive (S. aureus and M. luteus) and gram-negative (E. coli and V. harveyi) bacteria by disk diffusion method. The results of this research showed that Marcano’s method excluding the NaNO3, increasing the amount of KMnO4, and performing the reaction in a 9:1 mixture of H2SO4/H3PO4 improves the efficiency of the oxidation process. Marcano’s method provides a greater amount of hydrophilic oxidized graphene material as compared to Hummers’ method or two methods with additional KMnO4. The average size of the synthesis of GO with Marcano’s method was estimated by the Debye-Scherrer equation as around 19.7 nm. The results of this research showed that synthesized GO with four different methods did not have any antibacterial activities.

In this study, the performance of titania-silica catalysts with different loadings of titania was investigated in the photocatalytic degradation of Rhodamine B (RhB) dye pollutants under ultraviolet radiation. Moreover, two synthesis methods, i.e., dry and wet impregnation, were compared. It was shown that photocatalytic degradation of RhB was higher on the catalyst prepared via wet impregnation. To further improve the photocatalytic activity of the titania-silica, oxides of different metals including tungsten, bismuth, cerium, vanadium, iron, copper, silver, nickel, and zinc were used as promoters. The materials were characterized by Fourier-Transform InfraRed (FT-IR spectroscopy), X-Ray Diffraction (XRD), and N2adsorption–desorption to characterize the catalysts and find their structure-function relationships. It was found that the photocatalytic degradation of RhB over the titania-silica catalyst synthesized by wet impregnation containing 3 wt.% of tungsten oxide could achieve 98% after 240 min at reaction conditions of pH=6, initial RhB concentration=10 mg/L, catalyst dosage= 1 g/L, and temperature of dye solution= 25 ℃.

In this study, we have tried to provide a suitable catalyst for the oxidation of cyclohexane to obtain valuable products such as cyclohexanone and cyclohexanol. The magnetic ZrFe2O4/SiO2-NH-MnTCPP nanocomposite has been introduced as a heterogeneous catalyst for selective oxidation of cyclohexane to cyclohexanol with 100% selectivity and 36% conversion. Two methods have been used for this oxidation, reflux and solvothermal assisted by industrial microwave. The mesoporous ZrFe2O4 with nano cauliflowers structure was synthesized via the solvothermal route and to protect it in chemical media, a layer of SiO2 was deposited on the surface of nanoparticles via the wet method. Then, to modify with manganese tetrakis(4-carboxyphenyl) porphyrin (Mn-TCPP) was immobilized on nanocomposite to prepare ZrFe2O4/SiO2-NH-MnTCPP nanocatalyst. The characterization of all samples was done by Fourier Transform InfraRed (FT-IR) spectroscopy, X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-ray spectroscopy (EDX), Vibrating Sample Magnetometer (VSM) and nitrogen adsorption and desorption isotherms (BET). The catalytic activity of this magnetic nanocomposite in oxidation of cyclohexane was also evaluated by the GC-Mass instrument. Significant advantages of this catalyst include remarkable activity, separation from the reaction medium by the external magnetic field, adequate heat and reaction stability, reusability up to 5 times, and the selectivity in the oxidation of cyclohexane to cyclohexanol with appropriate productivity.

In this study, the effect of biochar catalyst on the pyrolysis process of light (LDPE), heavy (HDPE), and mixed polyethylene was investigated. For this aim, 30 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 decreased 11.96 and 16.08 wt% for HDPE and mixed polyethylene, but not for LDPE, indicating an increase in heavy vapor cracking. The amount of wax produced in the presence of a catalyst has increased 5.94 and 3.59 wt% for HDPE and mixed polyethylene excluding LDPE. The amount of liquid product obtained was increased for all three samples in the presence of biochar catalysts (from 12.30 to 16.69, from 38.21 to 46.19, and from 4.47 to 16.97 wt% for LDPE, HDPE, and mixed, respectively). Biochar increased the propane content for all three samples. This was due to the increase in cracking and conversion of heavy molecules to propane. Ethane content for LDPE decreased while for HDPE increased. This is indicating more breakdown of HDPE molecules and reaction of molecules with each other and with ethane to other products such as propane. Liquid product analysis showed that biochar catalysts tended to reduce compounds such as alcohols, indicating a tendency to deoxidize. In addition, biochar also caused the breakdown of larger and smaller aromatic molecules. The catalyst analysis indicated the presence of a coke layer on the catalyst, which contained more aromatic and oxygenated compounds.

A green protocol for the preparation of 4,5-diphenyl-2(R)-oxazoles from the reaction of benzoin, carboxylic acids, and ammonium acetate is described. This process is accomplished without the use of any organic solvent or catalyst. By this method, aromatic acids carrying electron-withdrawing groups reacted faster with higher yields. However, the reaction has generality for those with electron-donating groups and ortho-substituted ones. Even aliphatic carboxylic acids also provided the corresponding oxazoles in appropriate yields. Extraction of the product is simply achieved by the addition of water to the reaction mixture.

Effective removal of pollutants from industrial effluents in order to restore these waters to the cycle, and also from the environmental point of view is very important. BTEX is an indicator of Volatile Organic Compounds (VOCs). In this study, the BTEX adsorption method was applied to the MOF-199 nano-absorbent. the MOF-199 was initially synthesized by hydrothermal method and characterized by XRD, FE-SEM, and BET analyses. Adsorption test was performed under NPT conditions and HPLC technique was used for analysis, which confirmed the experimental results of absorption. The equilibrium adsorption isotherms were plotted at 298 ° K. According to the results, the BTEX adsorption isotherm with MOF-199 can be detected with Langmuir isotherm as well as Freundlich isotherm. by comparing the values of the maximum adsorption capacity (qmax) of compounds, the amount of MOF-199 adsorption capacity for benzene and xylene was 108.695 (mg/g), and for ethylbenzene and toluene, 107.526 and 83.333 (mg/g) was obtained, respectively.

Polyvinylidene fluoride (PVDF) and poly(vinylidene fluoride--chlorotrifluoroethylene) (PVDF-CTFE) hollow fiber membranes were fabricated via a wet phase-inversion method and the fabricated membranes were used for CO2 absorption with 1 M monoethanolamine solution in a gas-liquid membrane contactor system. Both types of hollow fiber membranes have a sponge-like structure close to the inner surface of the membrane and a finger-like structure close to the outer surface of the membrane but, the sponge-like structure of PVDF-CTFE membrane is thicker than PVDF membrane. The overall porosity of PVDF and PVDF-CTFE membranes were measured as 75.49 % and 69.51%, respectively. The critical Entry Pressure of water (CEPw) of PVDF-CTFE membrane is 9.5 bar and CEPw of PVDF membrane is 7 bar. The contact angle of water with PVDF-CTFE hollow fiber membrane surface is higher than PVDF membrane, which indicates higher hydrophobicity of this membrane. The maximum CO2 absorption flux of 7.20×10-3 (mol m-2 s-1) and 4.4×10-3 (mol m-2 s-1) at the liquid phase flow rate of 300 (ml min-1) was achieved for PVDF and PVDF-CTFE hollow fiber membranes, respectively. The results of the long-term CO2 absorption experiment showed that the CO2 absorption flux of PVDF membrane decreased by about 85% and reached 6.6×10-3 (mol m-2 s-1), 20 h after the beginning of the process. The CO2 absorption flux of PVDF-CTFE membrane decreased by about 15% and reached 8.8×10-3 (mol/m2.s), 70 h after the beginning of the process.

In this study, the hydrodynamic behavior of a conical fluid bed containing hydrophilic titanium oxide P25 nanoparticles and the formation of agglomerates were investigated. The particles with an initial diameter of 21 nm were fluidized by nitrogen and airflow at different superficial gas velocities. The size of the agglomerates during fluidization was determined by laser imaging and microscope electron diffraction (SEM) in the range of 40- 250 μm. According to laser images, the average size of agglomerates fluidized by nitrogen gas and airflow was 112 and 131 μm, respectively, while the average size of the complex agglomerates at the end of fluidization with nitrogen gas and airflow were 75 and 95 μm, respectively. The dynamical analysis of the bed showed that the size of the final agglomerates is highly dependent on the fluidization time. Due to the strong attractive forces between the nanoparticles, the size of the primary agglomerates was in the range of approximately 220-120 μm, which, with the continuation of fluidization, was broken down into smaller particles in the range of 145-100 μm. Young's modulus was calculated by fitting the displacement curve obtained from atomic force microscopy to 144 kPa, which corresponded to the Hertz model (141 kPa). The results indicated that increasing the gas velocity and applying airflow can partly increase the mean sphericity of particles (0.82-0.86). According to the experiments, fluidization time had a significant effect on the reduction of particle sphericity (0.58-0.75), which was affected by the failure of large agglomerates with sharp edges. The results showed that the initial agglomerates were fragile and have porosity above 80%, whereas the ultimate porosity was less than 50% with a relatively smooth surface. Unlike particle fluidization in cylindrical fluidized beds, the results of this study can help reduce particle agglomeration and achieve uniform particle size distribution.

Graphene aerogels are ultralight 3D graphene structures with a density of about 10 mg/cm3, unique electrical properties, and high compression capability. In order to produce them, first graphene hydrogel is produced, then the liquid in the graphene hydrogel is replaced by air so that the volume and structure of the gel do not change. For graphene hydrogel drying, special drying methods such as freeze drying or super-critical drying, or the newest drying method, which is ambient pressure drying using ice templating are needed. In this study, graphene aerogels were produced by ambient pressure drying without the need for special apparatus or specific pressure and temperature with a density of 10.6 g/cm3 and the preparation parameters were optimized. It was found that for the preparation of graphene aerogels with higher porosity and lower density, it is appropriate to select the initial concentration of graphene oxide 4 mg/ ml, the gelation time of 7 h, and the ice templating time of 48 h. It was also found that the lower-density aerogels were more compressive. As the stresses on the specimens increased, their electrical conductivity increased and their electrical resistance decreased. Their thermal conductivity was also measured as 0.029 W/m.K, which is in the range of good thermal insulation. The adsorption capacity of diesel oil, petroleum, edible oil, and ethanol by graphene aerogels was measured 88.5, 59.6, 42.6, and 55.2 g/g, respectively. Regarding the methylene blue adsorption, it was observed that the highest adsorption occurs in the first 15 minutes, so the graphene aerogels can be used as adsorbent of methylene blue and other dyes with similar structures from water and industrial effluents.

In this research, two different kinds of Carbon nanostructures (nanoporous graphene and multi-walled carbon nanotubes) were used for preparing silica nanohybrids with the sol-gel method and their Pickering emulsions properties were evaluated in order to the selection of the preferred Carbon nanostructure in preparing the related silica nanohybrid for Chemical Enhanced Oil Recovery (C-EOR). Therefore, we have prepared different carbon structures nanohybrids with SiO2 nanoparticles with different weight percentages. The samples were characterized with X-Ray Diffraction (XRD) Field Emission Scanning Electron Microscopy (FE-SEM) and Thermal Gravimetry Analysis (TGA). Pickering emulsions of these nanohybrids were prepared with n-Octane as oil model, suitable anionic surfactant (such as SDBS) and 2-Propanol as alcoholic co-surfactant at pH=7 in ambient temperature and with distilled water. Stability of the mentioned Pickering emulsions was controlled for one month. Emulsion phase morphology was investigated using optical microscopic imaging. Evaluation results demonstrated that the best samples are 70% Nano porous Graphene/SiO2 (both methods) and 70% MWCNT/ SiO2 Nano hybrid (method 2). Contact angle measurement results showed that the 70% Nanoporous Graphene/SiO2 Nano hybrid (method 2) is more effective for improvement of the stone reservoir wettability alteration from oil-wet to water-wet. Interfacial tension results indicate that the maximum amount is related to the injection of water and the minimum amount is related to the injection of Nano fluid of 70% Nano porous Graphene/SiO2 Nano hybrid (method 2). This result indicates preference of 70% Nano porous Graphene/SiO2 Nanohybrid (method 2) for decreasing the interfacial tension in comparison to the other samples. Therefore, 70% Nano porous Graphene/SiO2 nanohybrid (method 2) Pickering emulsion can be used for C-EOR.

A silicon substrate was developed for use in thermoacoustic motors as heat exchangers. Acetylene gas (C2H2) as a carbon source of argon gas (Ar) as a carrier gas for hydrogen gas (H2) is used to recover nanoparticles and iron nanoparticles as a catalytic source for carbon nanotube array growth. The reaction was carried out in a 48 cm long quartz tube and the gases were injected with a specified flow rate. Increasing the growth time from 10 to 30 min, there was little change in the diameter distribution and density of the synthesized carbon nanotube arrays. However, the thickness of the arrays increased from 15.62 to 16.76 μm. Carbon nanotubes grown at 30 min had better growth. The thicknesses (lengths) of the carbon nanotube arrays synthesized at temperatures of 750 and 800 °C were 75.42 and 60.98 μm, respectively. In general, the samples synthesized at optimum growth time and temperature of 30 min and 750 °C on the layered silicon substrate (with iron nanoparticles) by magnetic sputtering were quite desirable for use as a thermocouple converter.

Eco-friendly colorimetric sensors have wide applications in environmental science for simple, convenient, and fast detection of various analytes. In this work, a colorimetric sensor based on unmodified silver/silver chloride nanoparticles (Ag@AgCl NPs) was used for simple and fast detection of mercury (II) (Hg2+) ions. The fruit extract of Syzygium cumini was used as a reducing and capping agent for the biosynthesis of Ag@AgCl NPs. The synthesized nanoparticles were characterized by UV-Vis spectroscopy, Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction (XRD), and Fourier-Transform InfraRed (FT-IR) spectroscopy to verify the production, morphology, crystallinity, and surface functionalities of the synthesized Ag@AgCl NPs. The brown-yellow solution of the Ag@AgCl NPs synthesized by fruit extract of S. cumini became colorless in the presence of Hg2+ ions. In this procedure, the calibration curve had two linear range (first range from 1.0 to 5.0 μM with R2=0.9941 and second range from 7.0 to 111.0 μM with R2=0.9905). Also, the selectivity of the green synthesized Ag@AgCl NPs was studied to transition, alkali, and alkaline earth metal ions. The proposed method provides fast, simple, sensitive and selective detection and determination of mercury (II) in water samples.

A simple, green, precise, and sensitive method to determine trace amounts of Methyl parathion in aqueous solutions was used. In situ solvent formation microextraction based two components solvent system containing organic and aqueous phases. The organic phase contains hydrophilic ionic liquid namely 1-hexyl-3-methylimidazolium chloride [Hmim][Cl] and the aqueous phase contains an analyte of Methyl parathion. After mixing of two phases, the maximum mass transfer of the analyte from aqueous to organic phase was occurred and finally separation of phases use counter ion namely lithium bis(trifluoromethansulfonyl) imide. By adding of counter ion, hydrophilic ionic liquid [Hmim][Cl] caused anion exchange converted to hydrophobic ionic liquid [Hmim][NTF2] and phase separation was possible. Analyte enriched in organic phase after thermal desorption by using gas chromatography-flame photometry detection was determined. Effective parameters on extraction such as pH of the aqueous phase, amounts of ionic liquid, and the amount of counter-ion was evaluated and optimized. Figures of merit such as precision in the form of percent Relative Standard Deviation (RSD) for 7 replicate measurements equal to 1.2%, quantity Limit of Detection (LOD) of 0.39 µg/L, enrichment factor of 125, and linear range of 10-150 µg/L were obtained. Finally, the method was used successfully to determine amounts of methyl parathion in different aqueous and saline samples.

In this research, a simple, rapid, and effective microextraction technique, named “narrow-bore tube dispersive liquid-liquid microextraction” is introduced for the extraction and preconcentration of palladium from aqueous samples, followed by its UV/Vis spectrophotometric determination. To perform the extraction, a solution of palladium and cetylpridinium chloride surfactant was poured into a glass narrow-bore tube. p-dimethyl aminobenzilidene rhodanine (PDR), heptanol, and ethanol were used as the complexing agent, extraction solvent, and dispersing solvent, respectively. The effective parameters affecting micro-extraction efficiency; including type and volume of extraction and dispersing solvents, pH of the sample solution, concentration of surfactant and ligand, sample volume, and injection time were investigated and optimized. Under the optimized conditions, the calibration curve was linear in the range of 40-1300 µg mL-1 for Pd, and reproducibility (as relative standard deviation) was better than 5.5%. The limit of detection of the method was calculated to be 6.4 µg mL-1 with an enrichment factor of 37.5. The method was applied successfully for the extraction and determination of palladium in two mineral and tap water samples.

Walnut leaf has good antioxidant, antifungal and antimicrobial properties. In this study, a walnut leaf from different regions of Iran was collected and then its extract was analyzed by high-performance liquid chromatography-mass spectrometry (HPLC-MS). Antimicrobial properties of walnut leaf extract were evaluated by gram-positive bacteria of Staphylococcus aureus (ATCC29737) and Bacillus subtilis (ATCC 6633), gram-negative bacteria of Escherichia coli (ATCC10536) and Candida albicans yeast (ATCC10231) and by some linear multivariate calibration techniques, the peaks potentially responsible for the antimicrobial activity were indicated. The results of these techniques were displayed as regression graphs, which peaks with negative regression coefficients cause antimicrobial properties. Independent component regression was preferred to exhibit the potential antimicrobial active compounds in samples because of simplicity, better interpretation of regression coefficients, and its high repeatability. Finally, High Performance Liquid Chromatography -Mass Spectrometry (HPLC-MS) was used to indicate the structure of chemical components, which were responsible for antimicrobial activity.

One of the main challenges in the development of electric vehicles is their long charge time. Therefore, shortening the charge time of a lithium-ion battery (LIB) is a critical issue in this field. The charging process of the LIB is carried out by a constant current-constant voltage charger. The fast charge may affect the performance of LIB and accelerate its degradation. Herein a model is presented which can predict the charge time of LIB accurately in different C-rates so that the coefficient of determination is more than 0.99 in the modeling of five various LIBs. This indicates very good conformity between the experimental results and predictions of the proposed model. Since the constant voltage step in the charging process of the LIB continues as long as the current reduces to a certain value, if the current of this step is not detected correctly, an overcharge will occur. In the case of a perturbation in the LIB system, the current may not drop with a logical procedure, which can lead to an overcharge and capacity loss of LIB. Therefore, it is possible to limit the charge time in both constant current and constant voltage steps by accurate estimation of LIB charge time. This method can prevent further deterioration of LIB during fast charging.

Purification of alcohol is one of the research that is ongoing today. Meanwhile, liquid-liquid extraction is one of the most important methods of purification. Therefore, in this study, the purification of different alcohols was investigated by extraction using dibutyl ether solvent. Thermodynamic modeling of liquid-liquid equilibrium (LLE) of dibutyl ether+ alcohol+ water system was investigated at different temperatures. For this purpose, UNIQUAC and NRTL thermodynamic models were used and intermolecular interaction parameters were considered as a function of temperature. These parameters were obtained by optimizing an objective function. The objective function was considered as the mean-square deviation of the experimental data and the results of the models. The results of the modeling show the high accuracy of both models in estimating the composition of the component in different phases. The root means square deviation for UNIQUAC and NRTL models were 0.0191 and 0.0112, respectively. Moreover, the results show that dibutyl ether for the separation of heavier alcohols has a higher distribution coefficient and selectivity.

The main focus of the current work is to study the effect of phosphorous (PhS) and blast furnace slag (BFS) on the rheological behavior of blended cement. Two blended cement is developed, one with PhS and the other with BFS with 10, 20, and 30% of slags in a laboratory ball with to be well homogenized. The w/c ratio was considered 40%. Portland cement was used as the blank sample. Rheology of the produced blended cement as well as Portland cement was well fitted with the Bingham model. The viscosity of cement shows a constant trend but in the produced blended cement it increased with an increase in the usage amount of slag so that BFS samples show higher viscosity than PhS samples. Results showed that the rheology depends on the type and usage amount of slag. In a constant amount of slag, the BFS samples showed higher amounts in the main rheological parameters compared PhS. The plastic viscosity showed a decrease in the first 5 to 10 min and then an ascending trend was observed due to the progress of hydration in the samples.

In this study, machine learning tools were used to investigate the effect of various factors on the waste of caustic soda (NaOH) and alumina (Al2O3) and increasing carbonate (Na2CO3) pollution in the first stage of the Bayer process. The parameters studied in this paper are the concentration of Na2Oc, Na2Ou, Na2Ot and Al2O3 in the output solution to the wet grinding unit. The investigated factors included mass flow rate and chemical analysis of various compounds in bauxite and lime consumed, flow rate and chemical analysis of sodium alumina solution in a daily basis for 3016 days. In this study, Fourier Online Gradient Descent (FOGD) and Nysgd were used to model the process. The results show that the FOGD method has more accuracy and speed of learning than the NysGD method. These results indicate that each of these methods can model the process with high precision.