Iranian Journal of Chemistry and Chemical Engineering
Volume:42 Issue: 10, Oct 2023

A green and simple method was proposed for the synthesis of silver nanoparticles (AgNPLs) on novel Activated Carbon (AC) using glucose and dextrin as reducers and stabilizers of silver ions. Semecarpus Anacardium (SA) nutshells, an agricultural waste, were used as precursors to prepare low-cost Activated Carbon (AC) with a high surface area by chemical activation with KOH as an activator and different ratios of activating agents to the precursor. Silver nanoparticles (AgNPLs) on AC samples were synthesized using chemical and green procedures. Silver nanoparticles (AgNPLs) on AC samples were synthesized using chemical and green procedures. Surface functional groups in Fourier transform infrared spectroscopy (FTIR) spectra and X-Ray powder Diffraction (XRD) diffractograms including a broad peak in the range of 2θ =15–28◦ and a weak and broad peak in the range of 2θ =40–48◦, confirmed successful synthesis of AC. Also, the reduction of Ag+ to Ag0 and the presence of Ag2O were confirmed by XRD and SEM/EDX analysis. Scanning Electron Microscopes (SEM) reveals that the particles are spherical in shape and the Transmission Electron Microscopes (TEMs) images confirm the particle size distribution of the silver nanoparticles mainly in the range of 1–5 nm. EDX mapping was used to observe the exact distribution of silver nanoparticles on the planar carbon surface. The BET results indicate that the AC synthesized with the activating agent to precursor ratios of 1 has the highest surface area (717 m2/g) and the largest pore volume (0.286 cm3/g). Finally, the resulting Ag-AC was applied to study antimicrobial activity against gram-negative bacteria by risk diffusion and the agar well method. Silver nanoparticles distributed on the activated carbon surface had significant antibacterial properties. The sample from green synthesis with an AgNO3 solution concentration of 0.1 M  showed the most antibacterial effect.

In this study, the ability of Achillea tenuifolia aqueous flower extract was studied to synthesize silver nanoparticles (AgNPs) for the removal of Acid Red 18 (AR18) and Methyl Orange (MO) from aqueous media. UV-Vis spectroscopy, Scanning Electron Microscopy (SEM), energy-dispersive X-ray (EDX), Transmission Electron Microscopy (TEM), Fourier Transform InfraRed (FT-IR), spectroscopy and X-Ray Diffraction (XRD) analysis were used for the characterization of the prepared AgNPs. The effect of different experimental factors, including pH (3-12), adsorbent dosage (0.1-0.9 g), contact time (5-35 min), and initial concentration of dye (30-50 mg/L) was surveyed. Approximately 94% removal of dye was obtained at a pH of 3 for AR18 and 8 for MO, an adsorbent dosage of 0.9 g, a contact time of 25, and an initial concentration of 30 mg/L. The experimental data were better described by the Langmuir isotherm with the coefficient of determination (R2) of 0.9998 and 0.9995 for AR18 and MO, respectively. The maximum adsorption capacity (qmax) of 112.35 mg/g and 90.90 mg/g was obtained for AR18 and MO, respectively. The kinetic study revealed that the system fitted well with the pseudo-second-order kinetic model (R2=0.9992 for AR18, R2=0.9962 for MO). The results of this study demonstrated that synthesized adsorbent is low-cost and eco-friendly, which can be powerfully used for the removal of AR18 and MO dyes from wastewater.

Heavy metals such as copper are known as environmental pollutants and lead to irreversible damage to human health and other living organisms. This study aims to remove copper ions from aqueous solutions using a new adsorbent that includes the carboxylated Multi-Wall Carbon NanoTube (COOH-MWCNT) functionalized with 3-amino-dihydroxy benzo-indeno-furan (MWCNT-f) and in a discontinuous adsorption system. The results showed that MWCNT-f adsorbent can act as an effective adsorbent for the removal of copper ions so the maximum removal efficiency was 90.2% (pH 6, adsorbent mass: 0.3 g, and contact time: 45 min). The kinetic process of copper adsorption onto the mentioned adsorbent was found to fit the Morris-Weber kinetic model. Moreover, the equilibrium adsorption data indicated that Langmuir isotherm covers the equilibrium data with a maximum adsorption capacity of 16.78 mg/g for MWCNT-f. It was found the temperature increase possesses a positive effect on the removal efficiency of ions and it was achieved 95.76% at 50°C. The thermodynamic parameters demonstrated that the adsorption of copper on MWCNT-f, in the studied conditions, was spontaneous and thermosetting. The present study provides a new recyclable and efficient adsorbent for the removal of Cu (II) ions from aqueous solutions

The plant-based extract can be used to synthesize silver nanoparticles (Ag NPs) as a reducing agent. In the present study, Oregano leaves’ extracts were extracted using ethanol to synthesize Ag NPs. The effects of different parameters such as the processing time, temperature, and stirring rate on the mean particle size, concentration, and zeta potential of the synthesized Ag NPs solutions were optimized using Response Surface Methodology (RSM). At the optimum condition, which includes processing time (30.48 min), temperature (70 ºC), and stirring rate (370.530 RPM), Ag NPs were obtained with 33 nm of the mean particle size, 76.109 ppm of concentration, and +17.2 mV of zeta-potential. In this condition, Ag NPs displayed high antibacterial activity against Gram-negative and Gram-positive bacteria. In addition, the maximum antioxidant activity of 11.7% was obtained at optimum synthesizing conditions.

In this study, NiO films were processed on p-type Si by magnetron sputtering technique under the mixture of argon (Ar) and oxygen (O2) gas atmosphere at room temperature and 300 0C. The microstructure, nanoindentation, and electrical properties of the NiO films were compared with the as-deposited and subsequent vacuum-annealed films at 300 0C for one hour. The grain size and phase structure of NiO films were determined by an X-ray diffraction study. The microstructure and morphology of the resultant NiO films were analyzed by Field Emission Scanning Electron Microscopy (FESEM) and transmission electron microscopy (TEM). The results show that NiO films were nanocrystalline with grain size in the range of 14-32 nm. The formation of NiSi2 was noticed at the interface of vacuum-annealed NiO films. Nanoindentation results showed an increment in the hardness of annealed NiO films over as-deposited films at the same temperature. In contrast, Van der Pauw's four-point probe method showed a reduced resistivity of vacuum-annealed NiO films which can be potential candidates for electrical contact applications.

In this study, polyaniline nanocomposite with aluminum oxide (PANI/Al2O3) was synthesized in situ polymerization method and the anti-corrosion ability of nanocomposite was investigated. Products were identified by chemical analysis of Fourier Transform InfraRed (FT-IR) spectroscopy, X-ray crystallography (XRD), and thermal weighing calorimetric analysis (TGA). Also, anti-corrosion properties were analyzed by Open Circuit Potential (OCP)analysis, Electrochemical Impedance Spectroscopy (EIS), and potentiodynamic polarization curves. To investigate anti-corrosion performance, different percentages of nanocomposites (3, 6, 9, and 12 %) were added to industrial paint and applied to steel sheets as a coating. The results of corrosion performance illustrated that the steel sheets coated with PANI/Al2O3 nanocomposites along with the paint, have less corrosion compared to the samples of pure steel sheets and the cases coated with PANI/Al2O3 nanocomposites. Also, the 6 % coating containing PANI/Al2O3 nanocomposite along with paint on steel sheets showed the best anti-corrosion properties. The open-circuit potential analysis results make it clear that the coatings containing PANI/Al2O3 nanocomposite with paint have a higher performance compared to pure paint coatings in 3 wt% NaCl solution. EIS analysis revealed resistance of the coating containing 6 % PANI/Al2O3 along with the paint is more than other samples in 3 % NaCl solution.

Dopamine (DA) is a vital neurotransmitter having key roles in regulating various biological functions in animals and the sensitive and selective monitoring of DA in biological fluid is of high significance. Herein, poly(1-naphthylamine)–graphene oxide (PNA-20GO) nanocomposite containing 20 % GO by weight obtained by the in-situ chemical oxidative polymerization of 1-naphthylamine in the presence of GO was utilized to develop an economical electrochemical sensor for DA by modifying Carbon Paste Electrode (CPE) with prepared PNA-20GO nanocomposite. The electrochemical characterization of the PNA and PNA-20GO was performed with Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopic (EIS) studies. The electrochemical response and charge transfer kinetics were significantly improved for the PNA-GO-modified CPE compared to PNA-modified CPE which was evidenced by the comparatively lower diameter of the semicircle region in the Nyquist plot obtained from EIS studies and better current response for the PNA-GO modified CPE than PNA modified or bare CPE in the corresponding CV curves. The enhanced electrochemical characteristics were credited to the increased surface area and synergistic charge transfer interactions between the PNA and GO. Furthermore, it was observed that PNA-GO modification could trigger the diffusion-controlled electrochemical oxidation of DA over CPE. The demonstrated PNA-GO modified DA sensor could show the linear current response for DA concentration ranging from 1-100 µM. The sensor exhibited high sensitivity (1094 µA/(mM.cm2)) with a low detection limit of 0.23 µM. The present DA sensor could exhibit acceptable stability and selectivity over common interfering molecules like creatine, ascorbic acid, and uric acid.

One of the newest methods to remove pollutants from water is the use of magnetic chitosan nanocomposites. Here for the first time, we used two phosphoramide compounds, N-Nicontinyl-N', N"-bis (piperidinyl) phosphoric triamide (P1) and N-Nicontinyl- N', N"-bis (4-methyl piperidinyl) phosphoric triamide (P2), in the structure of chitosan-based magnetic nanocomposites for the removal of Cu (II) ions from aqueous solution. The two chitosan/Fe3O4/ phosphoric triamide nanocomposites, NC1 and NC2, prepared using P1 and P2 respectively, were characterized using XRD, EDX, VSM, SEM, BET, and BJH methods. Removal of Cu (II) ions from polluted water was tested in different user conditions: pH (3-11), adsorbent dosages (5-25mg), and contact time of adsorbent with aqueous solutions (5-600 min). AAS (Atomic Absorption Spectroscopy) results showed that with increasing pH from 3 to 9, the amount of removal of Cu(II) ion increased, and with increasing pH from 9 to 11, the removal rate decreased. Heightening the contact time until 451 minutes also enhanced the removal efficiency up to 97.44%; After this time, the reduction of the removal amount was observed probably due to the desorption phenomena. Similarly, with the increasing amount of adsorbent (from 5 to 25 mg), the removal of Cu(II) ion increased too. Using Response Surface Modeling (RSM) the different conditions were transformed into RSM parameters and a second-order quadratic model was built to minimize the number of runs (36 runs) and also predict responses. A good correlation (with R2 = 0.9237) was found between the experiment and the statistical model, for removing Cu(II) ions from the aqueous solution using these adsorbents.

Defective MOF-801 (Zirconium-fumarate metal-organic framework) was de novo synthesized using environmentally friendly ultrasound-assisted synthesis. The effect of the modulator on the crystallinity, morphology, density of missing linkers, pore volume, and the specific surface area (BET) of synthesized MOF-801 was studied using two modulators, acetic acid, and formic acid, in different quantities. The MOF-801 sample (MOF-801-100FA) was applied to investigate the adsorptive removal of two cationic dyes viz Crystal Violet (CV) and Methylene Blue (MB) from an aqueous solution in a single system. MOF-801-100FA was found to be more effective in removing MB dye than CV dye. The maximum equilibrium adsorption capacity was 30.4 mg/g and 18.9 mg/g with MB and CV dyes having an initial concentration of 50 mg/L. Langmuir and Freundlich isotherm models were the best fit for adsorption data based on linear regression analysis. The best kinetic model for the adsorption was pseudo-second-order kinetics (R2 = 0.9975 for CV dye and 0.9998 for MB dye). The effect of dye concentration, contact time, MOF dose, and pH of dye solution on the adsorption of dyes was also investigated. The study showed that defective MOF-801-100FA is an efficient adsorbent for the removal of CV and MB dyes from aqueous solution.

The study examines the possibility of removing Methyl Orange (MO) from aqueous solutions using crude bentonite. SEM-EDX (scanning electron microscopy) and XRD (X-Ray Diffraction) analyses were performed to characterize the material. Batch experiments were performed on the adsorption process to study the effect of contact time, pH, concentration, and temperature. The results indicate that the equilibrium reaches after 2 h of contact. The MO adsorption followed the Langmuir-Freundlich and Baudu models with a maximum adsorption capacity of 308 mg/g. The adsorbed capacity of the material is best at pH=3. The adsorption capacity increases with temperature.  In addition, the Central Composite Design (CCD) in Response Surface Methodology (RSM) and Artificial Neural Network (ANN) were used to evaluate the simultaneous interactions of independent variables. The results suggest that the initial concentration was the dominant parameter in the adsorption process. The monolayer model with two energies derived from statistical physics can be adapted to interpret the adsorption data. Physical adsorption forces were predicted to be responsible for the removal of the dye. This study provides new information on the adsorption mechanisms of pollutants commonly found in water.

The present study investigates the impacts of the extract of Trachyspermum leaves on mild steel corrosion in 0.1M hydrochloric acid (HCl) while highlighting its inhibitory mechanisms. The effects of mild steel corrosion in solutions of HCl were examined using gravimetric and galvanostatic polarization techniques, along with EIS analyses. The EIS data shows the highest coating undamaged index (83 %) after 100 hours of immersion. According to the results, the maximum inhibitory effectiveness corresponding to the minimum corrosion rate could be observed at the highest desirable level of inhibitor concentration equal to 100 ppm, while the corrosion rate decreases with an increase in the extract concentration. The adsorption study promotes that Langmuir isotherm with -31.85kJ/mol in room temperature with R2=0.95 best describes the metal surface interaction with the Trachyspermum leaves extract with the best exposure time for the Trachyspermum to adsorb to the metal surface at all concentrations. SEM, AFM, IR, and XRD showed good coverage of Trachyspermum on the surface of mild steel. Based on the polarization results, the inhibitors can play the role of a mixed inhibitor, which is confirmed by the computational data. The chemical potentials of thymol, cymene, and terpinene are -6.55, -6.91, and -6.49 eV respectively.

Coastal area construction provides the biggest challenges in the country's development. Mechanical strength and durability are the two main challenges in coastal areas when compared to conventional construction. The proposed study explores the effect of recycled melamine powder and  poly (vinyl-co-ethylene) copolymer on workability, setting time, aggregate-to-cement adhesion, and the effect of moisture and saline water on concrete mechanical properties. Portland cement was sieved and dried sand, and aggregate was mixed in the ratio of 1:2:4 (cement: sand: aggregate) by weight. The three constituents were manually mixed with 40-45 wt. % tap water, based on cement content, until a homogenous mixture was visibly observed. Cylindrical samples with continuous tampering to avoid voids were cast in standard molds of 4”x 8” (100 x 200 mm) dimensions. The molds were covered and left for 24 hours for setting. Unmolded concrete samples were cured for 7 and 28 days in tap water. The concrete samples were dried and stored for further testing. The same concrete samples were prepared with an additional 1 wt. % and 3 wt. %, based on the cement content, of melamine and poly(vinyl-co-ethylene) copolymer. The samples were subjected to water slump height, water permeability, compressive strength and flexural tests, and carbonation tests. The results showed a 10 % and 16 % decrease in slump height for 1 % and 3 % loadings, respectively for both polymers when compared to controlled samples. Reinforced concrete showed less water penetration for both polymers due to their hydrophobic nature. Higher compressive and flexural strengths and low carbonation depth were obtained for reinforced concrete irrespective of the polymers used in this research.

A continuous-flow synthetic platform utilizing a microchannel reactor was developed here to realize the gram-to-kilogram scale-up synthesis of 2,2’-diallylbisphenol A (DABPA) via thermal Claisen rearrangement with high efficiency and safety. The optimal reaction temperature of this thermal rearrangement was confirmed firstly by differential scanning calorimetry and then the classical batch synthesis was carried out to find that large quantities of reaction heat were accumulated, which not only promoted the formation of many by-products but also would bring various uncontrollable risks such as bumping. Thus a simple continuous flow synthetic platform was constructed which employed a microchannel as the reactor. The optimal working temperature of this reactor and the flow velocity of the reactant were screened and established. Compared with the conventional batch method, the utilizing of a flow reactor avoided a large amount of reactant staying in the reaction mixture and minimized the accumulation of reaction heat, which not only enhanced the safety of the reaction process but also prevented the formation of many by-products, delivering a practical strategy for the scale-up synthesis of DABPA.

The extraction of keratin from natural feathers has been studied for its use in various cosmetics and drug delivery applications. There are various reducing agents to dissolve the hard keratin such as sodium dodecyl sulfate and 2-mercaptoethanol, in the present work, a novel extraction methodhas been developed using sodium sulphite, sodium bisulphite, and sodium dodecyl sulfate in the presence of urea, 2-mercaptoethanol, Ethylenediaminetetraacetic acid (EDTA), and thiourea. To increase extraction yield, the weight of feathers, time of incubation, pH, and temperature were investigated using a Central Composite Design and Mixture plan for Optimization. With the present process, we evaluated the apport of keratin treatment and extraction techniques utilizing sodium sulphite, sodium bisulphite, and sodium dodecyl sulfate in the presence of urea, 2-mercaptoethanol, Ethylenediaminetetraacetic acid (EDTA), and thiourea. The percentage yield and keratin concentration were measured using UV-Vis absorbance, Bradford, and Biuret assays. Then, the protein profile and their functional groups were characterized using Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) and Fourier Transform Infrared Spectroscopy (FTIR). The purpose was to compare the different procedures in terms of keratin protein quality and quantity, as well as their cost-effectiveness, and to determine the optimum conditions for the keratin extraction process. The results proved that the yield of white chicken feathers keratin (81.2 %) increased using sodium sulphite (1M), sodium bisulphite (0.1 M), and Sodium Dodecyl Sulfate (0.1 M).  The highest protein production was measured at 80°C in 10 h with 5 g of feathers at pH 10. This process of keratin extraction can be used from the laboratory to industrial production with high recoverability and stable properties.

Diabetes is a complex metabolic disorder that can cause changes in the composition and function of saliva. Therefore, it seems that the study of saliva composition in patients with diabetes will help in its diagnosis, prognosis, and complications. The present study aimed to compare the saliva’s lysozyme and glycosylated lysozyme levels of patients with type 2 diabetes (T2D) in comparison with healthy individuals. Lysozyme and glycosylated lysozyme levels of salivary samples were measured using ELISA method. The results of this study showed that salivary lysozyme levels were lower in T2D patients. Meanwhile, the salivary glycosylated lysozyme levels were higher in T2D patients compared to control (p≤ 0.001). Salivary lysozyme levels in patients with long-term diabetes (more than three years) were significantly lower than those of T2D patients having the disease for three years. Also, salivary glycosylated lysozyme levels were significantly higher in patients with long-term diabetes (more than three years) than in patients with short-term diabetes (less than three years). In conclusion, the results of this study demonstrated that the salivary lysozyme level in patients with T2D was lower than in healthy individuals. Also, the salivary glycosylated lysozyme level of the T2D patients was higher than healthy individuals. Increased duration of T2D affliction also appears to be associated with increased salivary glycosylated lysozyme levels. Moreover, the increase of salivary glycosylated lysozyme was greater in patients with T2D than in healthy individuals. These findings indicate the important role of salivary glycosylated lysozymes in diagnosing and predicting the complications of diabetic patients.

A pioneering approach for the spectrophotometric inquisition of microscale amounts of iridium (III) under aqueous conditions has been explored using a novel benzopyran derivative, 3-hydroxy-2-(4-methoxyphenyl)-4H-chromen-4-one (HMPC) as a ligand, hence, employing complexation as a basis of reaction between the two. The spontaneous complexation between iridium (III) and HMPC is manifested by the expeditious formation of a pale yellow complex at pH 4.87 in which the metal-to-ligand ratio [M:L] is estimated as 1:2. The complex absorbs paramountly at 423-430 nm and is markedly stable. For ensuring the formation of a stable complex, optimal conditions have been fixed concerning the parameters regulating its formation. Accordingly, the system shows coherence to linearity between 0.0-1.7 µg/mL of iridium (III). The molar attenuation coefficient and Sandell’s sensitivity are 6.824×104 L/mol cm and 0.00281µg Ir (III) cm-2, respectively at 425 nm. Statistical parameters including RSD, correlation coefficient (r), and detection limit are respectively, 0.2169%, 0.9999, and 0.0123 µg/mL. As a check for flexibility and usability of the method, intervention concerning complexing agents and cations of prime analytical importance has been carried out indicating the majority of these do not induce any interference during determination. The accomplished studies serve as proof of the versatility, flexibility, and sensitivity of the method. Keeping in view the aforesaid characteristics of the complex, it was subjected to numerous biological investigations and has been satisfyingly found to possess anti-cancerous, bactericidal, and antioxidant properties thus expanding its novel utility domain in the therapeutic world. Quantum chemical parameters (DFT and MEP), based on analysis of electronic properties of the complex in its most stable least energy conformation, are used to better understand the chemistry of the produced complex.

In this research, a simple, rapid, and reliable method was developed for isolating and quantifying the primary preservative compound (sodium benzoate (NaB)) and some water-soluble vitamins such as ascorbic acid (C) and five vitamin B compounds, including thiamine hydrochloride (B1), riboflavin-5-phosphate sodium (B2), nicotinamide (B3), pantothenic acid (B5), pyridoxine hydrochloride, (B6) in multivitamin syrup. An ODS column (temperature 35 °C) and a UV detector were used. The mobile phase was pH 3.0 phosphate buffer-methanol at a flow rate of 1.0 mL/min in a gradient elution approach. The analytes mentioned above were separated in 40 min. Method validation was reached by evaluating the detection limit (LOD) and quantification limit (LOQ), accuracy, and instrument precision. The data obtained in real sample analysis agreed with the declared values. The data obtained for under stress multivitamin syrup sample (forced degradation) confirmed no interference effects in the quantification of analytes.

This study aims to find the well-coated Dunaliella Salina Microcapsule (DSM) and use it as a supplement for sago bagea cookies. DSM formulas will be produced from the encapsulation of maltodextrin and Arabic gum by spray drying method, and their morphologies will be analyzed using a Scanning Electron Microscope (SEM). The best formula is chosen based on wrinkles that appeared and agglomeration on the particles of the produced microcapsules. Based on the SEM result, it is obtained that F3 is the well-coated microcapsule due to its less-wrinkled surface with no agglomeration. F3 will be used to fortify sago bagea cookies with ratios of 10%, 20%, and 30%. In this study, four sago bagea cookie formulas were made (Control, DSM 10%, DSM 20%, and DSM 30%). These formulas will be tested by sensory evaluations to determine the preferred cookies, which will be analyzed further for their nutritional values. Based on the sensory analysis, DSM 10% will be chosen due to panelist preference, with the highest overall acceptability score of 3.94 ± 0.71. DSM 10% will be analyzed on its omega-3 fatty acids (docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)) and nutritional compositions. In conclusion, the analysis showed DSM 10% has a higher content of DHA (4.705 mg/g to 7.305 mg/g), EPA (15.18 mg/g to 20.18 mg/g), ash (0.71% to 0.77%), fat (13.84% to 15.56%), protein (2.72% to 3.89%), crude fiber (1.33% to 1.34%) and total energy (456.28kcal/100g to 467.16kcal/100g) but lower in moisture (2.52% to 1.80%) and carbohydrate (80.21% to 77.98%) than control.

A sensitive electrochemical method for the detection of trace heavy metal ions such as lead Pb (II) and cadmium Cd (II) using a Carbon Graphite Electrode (CPE) chemically modified by a dolomite powder was applied. Firstly, local Moroccan dolomite was deeply characterized  in order to understand its chemical composition and morphological structure. The performance of this sensor is revealed by three electrochemical methods Square Wave Voltammetry (SWV), Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS). The effect of preconcentration time, concentration effect, media pH, and interference ionic response to the electrochemical response of the working electrode were all investigated under various experimental settings. The SWV determination coefficient (R² (Pb (II)) = 0.8385 and R² (Cd (II)) = 0.9307) is lower than the cyclic voltammetry result (R² (Pb (II)) = 0.989 and R² (Cd (II)) = 0.977), showing the latter's superior predicting ability. Even in the presence of interfering ions, the suggested electrochemical sensor exhibits good repeatability and selectivity, with detection limits of 0.10113 μM and 0.22227 μM for Pb2+ and Cd2+, respectively. These values ​​obtained from the calibration curves of the substances studied reveal that the developed sensor showed excellent electroanalytical performances for the detection of heavy metal ions. According to Atomic Absorption Spectroscopy (AAS), the prepared electrode from CPE-dolomite showed a highly sensitive capacity toward cadmium detection with a content of 178.43 mM after mineralization of the electrode immersed in CdSO4 solution. The same electrode was used to reduce the lead in which the resulting solution was analyzed involving a value of 125.23 mM.

Contamination of soil, water, and air with heavy metals is an environmental issue and of particular importance due to its toxicity, persistence, and mobility in soil. For a better understanding of the environmental behavior and risks associated with heavy metals, modeling their fate and transport is prioritized as an efficient tool. In the present research, the transport of the heavy metals cadmium (Cd), nickel (Ni), and zinc (Zn) in two disturbed and undisturbed loamy soils with the initial concentrations of 50, 100, and 150 mg/L was simulated using CXTFIT and Hydrus-1D as analytical and numerical models, respectively. The results showed that both the models can simulate the transport of heavy metals and describe the BreakThrough Curves (BTCs) with a coefficient of determination (r2) of higher than 0.9 and a root mean square error (RMSE) of less than 0.06. However, the analytical CXTFIT model showed a better fit to the BTCs compared to the numerical Hydrus model. Also, the models showed better efficiency in the disturbed soil than undisturbed soil. With the increase in the concentration of all the three heavy metals, the retardation factor (R) decreased and indicated a trend as Zn>Ni>Cd. The hydrodynamic dispersion coefficient (D) in the undisturbed soil was estimated to be higher than in the disturbed soil and followed the trend of Cd≥Zn≥Ni. The evaluation of the results showed that despite the better performance of the CXTFIT model, there is no major difference between the two models.

This study focused on developing a new membrane-type by incorporating magnetic iron oxide nanoparticles (Fe3O4) into a polyethersulfone (PES) matrix to create a Fe3O4/PES membrane. The synthesized membrane was characterized using various techniques, including SEM, Map, 3D images, TEM, XRD, and FTIR, to determine its structure and properties. The membrane's performance was evaluated by examining parameters such as water contact angle, membrane pore size and porosity, water content, Pure water flux (PWF), and salt rejection. The results showed that the Fe3O4/PES membrane outperformed the pure PES membrane regarding water flux and salt rejection. The membrane with a Fe3O4 concentration of 0.01wt.% had the highest flux value of 16.35 (L/m2h), while the virgin membrane's flux value was only 2.81 (L/m2h). Furthermore, the salt rejection of the modified membrane increased from 60% to 90% compared to the pure PES membrane.  It was observed that the Fe3O4 nanoparticles, which had a positive charge of 3-7 nm, tended to agglomerate and increase in size when the Fe3O4 concentration was increased, leading to a negative surface charge. By using fewer Fe3O4 nanoparticles, the Fe3O4/PES membrane achieved similar performance as other research, making it a more cost-effective option.

Gel propellants have the advantages of both liquid and solid propellants and present a promising future for the aerospace industry. Many gel propellants have shear-thinning behavior, which complicates their behavior in propulsion systems, especially the atomization process. On the other hand, the toxicity of many gel propellants makes the study of their dynamic behavior difficult. In the present work, non-toxic gel simulants were first prepared using a variety of gelling agents. Next, a gel simulant with a behavior similar to UDMH's basic gel fuel was selected from the prepared simulants. The dynamic behavior of the selected simulant gel was studied by different shear-thinning fluid models, and the most suitable rheological model was chosen. Eventually, the simulant gel dynamic behavior was simulated in a pressure swirl injector using the selected rheological model, and the results were compared to the experimental data. The results indicated that the simulant gel made from 0.85 wt.% of HPMC gelling agent is very similar to the basic UDMH gel in terms of dynamic behavior and power law index. Furthermore, among the rheological models, the Carreau-Yasuda model was able to predict the selected gel simulant behavior in a wide range of shear rates. A comparison of the experimental tests and numerical simulation of the gel simulant flow inside the swirl injector revealed that using the calculated constants of the Carreau-Yasuda model can predict the simulant gel dynamic behavior and the functional characteristics such as mass flow rate, discharge coefficient, and spray cone angle with less than 6% error.

Dimethyl aminoethyl azide (DMAZ), as a novel liquid fuel, is a good candidate for use in the upper stage of space rockets. One of the new features for the liquid fuel with conventional liquid oxidizers AK27 and nitrogen tetroxide (NT) is the dry mass estimation of tanks and thickness used for the tanks of DMAZ/AK27 and DMAZ/NT bipropellants through simple relations instead of complex relations. The oxidizer to fuel (O/F) ratio, as an important parameter, was applied for the estimations. In other words, the summation of the dry mass of tanks and bipropellants was calculated at certain values of O/F ratios. Moreover, the application of this simple method was developed for liquid fuels monomethyl hydrazine (MMH) and unsymmetrical dimethyl hydrazine (UDMH) with the liquid oxidizers. RPA software was used to find the optimum O/F ratio. The results showed that at a combustion chamber pressure of 15 bar, exit pressure of 0.001 bar, operation time of 480 seconds, and 7kN thrust, the lowest and the highest dry masses belong to NT/DMAZ and NT/MMH propellant tanks, respectively. Also, NT/MMH and AK27/DMAZ have the lowest and highest summation masses, respectively.

Phase Change Materials (PCMs) have recently found a wide range of new application opportunities. In this study, PCMs microcapsules have been synthesized with urea–formaldehyde polymer shell. The microcapsules have been characterized by FT-IR, SEM, TEM, and DSC analysis. Then, the thermophysical characteristics of the MEPCM suspension including the thermal conductivity, and viscosity have been measured at different particle concentration (2, 5 and 10 wt%) and different temperatures from 25 to 50 °C. New correlations are developed to predict the thermophysical characteristics of MEPCM suspensions. This work provides a practical and efficient synthetic strategy for the preparation of MEPCMs, which is expected to present a promising future in the field of energy storage.

The need for drinking water is increasing daily, and many research works have been carried out on converting seawater into drinking water. Natural conversion solar desalination systems were popular for producing fresh water, but the main constraint is their low yield. This paper discussed the performance variation of single slope solar still with four new different combinations proposed in this study with an objective to improve the solar still yield, i) With Insulation-Without Dish (WI-WoD), ii) Without Insulation-Without Dish (WoI-WoD), iii) Without Insulation-With Dish (WoI-WD) &  iv) With Insulation-With Dish (WI-WD). The still was made up of stainless steel with an area of 0.25m2. The insulation was carried out with two layers of materials: the inner layer with thermocol and the outer layer with plywood. The bottom of the still was not insulated, and the solar concentrator dish was used to focus solar radiation on increasing the still water temperature, which led to an improved yield of the system. These experiments were conducted under the climatic conditions of 13o 8’ 58.05” N, 80o 11’ 32.38” E, at Chennai, Tamilnadu, India. This study found that WI-WD produced the highest yield compared to other combinations. The WI-WD combination produced a 25.49% higher yield as compared to the conventional still (WI-WoD). The energy and exergy efficiency analysis were carried out for the WI-WD combination, and the values obtained are 30.06 and 1.6%, respectively. The WI-WD combination produced higher energy and exergy efficiencies compared to conventional still. The results state that the maximum hourly exergy destruction in basin liner, saline water, glass cover, and dish concentrator are observed as 716.53, 53.82, 82.99, and  3836 W/m2, respectively.

We report the modeling and simulation results of thin film InP/GaAs dual-junction solar cell devices. The photovoltaic devices of varying device thickness in a range of 1-5 µm were modeled and optimized by modulating hole and electron concentrations in p-and n-doped active layers, respectively, and the thickness of the n-and p-regions in the devices. Our findings show that, with an increase in the thickness of active layers, the efficiency of solar cells increases which resulted in efficiency values in a range of 31.8%-36.4% under 1 sun of AM1.5G at 300 K. Furthermore, the optimized solar cells were further investigated under different working temperatures, black body temperatures, and solar spectra. For the working temperature range of 300 K-373 K, the efficiency of the device degraded with the increase in temperature. In the black body temperature range of 2000-8000 K, the device exhibited an enhancing trend of efficiency when temperature increased and the highest efficiency of 31.9% was achieved at 6500 K. Due to their lightweight, low cost with much thinner device structure, and higher energy conversion efficiency, the thin film solar cells demonstrated here have advantages over conventional Si or other semiconductors-based solar cells for applications in photovoltaic, thermal photovoltaic, and space power.

Solar thermal (ST) collectors could only generate thermal power, while photovoltaic thermal (PVT) systems could provide both electricity and thermal power. However, the PVTs outlet temperature is usually not high enough for use in many applications such as space heating. Therefore, a new system called PVT system and ST collector in series (PVT-ST) is inducted to generate thermal power with higher outlet temperature and electricity. This paper explores the potential and feasibility of using PVT-ST under relatively hot and dry weather conditions in four cities of Tehran, Abadan, Baghdad, and Basra. To this end, the yearly performance of the system in terms of the first and second laws of thermodynamics is numerically evaluated. Moreover, the effects of the working fluid mass flow rate, in both laminar and turbulent regimes, on the module performance are investigated. Additionally, a comparative study is made between the PVT-ST, single PVT, and single ST systems. The working fluid regime analysis reveals that optimal thermal and electrical efficiency can be obtained in a turbulent regime. While the turbulent regime reflects better electrical exergy, the thermal exergy is dramatically decreased by raising the mass flow rate. Considering the mass flow rate of 0.0304 kg/s (turbulent regime) in July, the thermal efficiencies of the single ST, PVT-ST, and single PVT systems are 85.7%, 78%, and 72.9%, respectively. However, regardless of the mass flow rate, the PVT-ST system has the highest thermal exergy, peaking at 14.56 W/m2 at the lowest mass flow rate (laminar regime), which is double the thermal exergy of the single PVT. Finally, the annual study of the system performance in different cities illustrates that the maximum thermal power and exergy can be produced in Basra, averaging 375.72 and 1.46 W/m2. However, the maximum electricity production, with  an average of 77 W/m2 belongs to Baghdad.

This study aims to improve power for stirrer vessel equipment by involving the parameters like diameter of solid particles; tank diameter, height, and density of slurry are varied with weight percentage. The above parameters affect Zwietering's mass ratio, the kinematic viscosity of the slurry, Reynolds' number, Froude's number, impeller diameter, and just suspension speed. In the metaheuristic technique, the Ant Colony Algorithm is among the best algorithms for solving nonlinear problems. From ACO among propeller, Paddle, and Rushton impeller, the Rushton impeller has more power value of 8856.70W. In sensitivity analysis by keeping ants constant by varying iterations and by keeping iterations constant varying ants the Rushton impeller has a higher power value when compared with the propeller impeller and paddle impeller

Delamination is a severe threat to the wide use of composite laminates in primary structural applications. Delamination grows under fatigue loading and leads to structural failure. Very few studies exist on mixed-mode delamination on carbon fiber however glass fiber was not studied under mixed mode. The objective of this paper is to investigate fatigue delamination growth under mixed-mode loading in Glass Fiber Reinforced Polymer (GFRP). A mixed-mode bending fixture was developed and fabricated. Fatigue delamination growth tests were performed for different mixed-mode loading using that fixture. With the help of a Scanning Electron Microscope, micro examinations of the crack surface were carried out. The results showed a high growth rate for the case with more contribution of mode I. The Fractographic investigation performed on the different samples showed the existence of mode-I and mode-II features and broken fiber’s confirming fiber bridging during delamination growth. The fractographic features varied systematically with mode shift.

Wax and asphaltene precipitations cause many problems and high costs in the petroleum industry; therefore, the significance of studying these depositions' behavior is considerable. Evaluating the asphaltene effect on wax precipitation can help find the behavioral trends of waxes and prevent them from precipitating. In this paper, Iran Asmari reservoir Dead Crude oil (IADC) and asphaltene from this oil were used for the experiments. The extracted asphaltene was analyzed by FT-IR analysis. The pour point and wax precipitation content were determined according to the ASTM-D97 Standard test and modified UOP 46-64 method, respectively, and Wax Appearance Temperature (WAT) was measured via differential scanning calorimetry (DSC). At low asphaltene concentrations (0 and 0.057 wt %), adding asphaltene decreased the pour point and wax precipitation content. At asphaltene concentrations of 0.057 wt %, the least wax precipitation content and pour point were measured. A rise in pour point and wax precipitation content was observed at more asphaltene concentrations (0.057-20 wt %). The wax appearance temperature of IADC (36.5 °C) has been decreased in asphaltene-free IADC (25.1 °C). By changing the asphaltene concentration from 0 to 0.1 wt %, the behavior of wax precipitation changed intensely, and this behavior varied gently by increasing the asphaltene concentration from 0.1 to 20 wt %.