Vida Haji Aghaei; Narges Ajami
Abstract
In this paper, graphitic carbon nitride (g-C3N4) was prepared by direct pyrolysis of melamine and then used to synthesize P-doped graphitic carbon nitride nanosheets with ultrasound in phosphoric acid. This simple method helps increase the trapping of light, change the electronic property of g-C3N4 and ...
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In this paper, graphitic carbon nitride (g-C3N4) was prepared by direct pyrolysis of melamine and then used to synthesize P-doped graphitic carbon nitride nanosheets with ultrasound in phosphoric acid. This simple method helps increase the trapping of light, change the electronic property of g-C3N4 and prevent charge recombination in the as-prepared photocatalyst. The useful features of this method to prepare P-doped g-C3N4 nanosheets are its simplicity, short synthesis time, economical and environmentally friendly. The present study demonstrates the ability of phosphoric acid to synthesize P-doped g-C3N4 nanosheets with ultrasound, which leads to an increase in photodegradation of Tartrazine under visible light.
Soghra Fathalipour; Sima Pourbeyram; Sanaz Lotfi; Rasul Bulgar
Abstract
Silver nanoparticles (Ag NPs)-reduced graphene oxide was prepared through the in situ nucleation of Ag NPs on reduced, modified GO (rMGO). Glycine was used as a green reducing as well as modifier agent for GO to obtain rMGO. Nucleation of Ag NPs on rMGO was carried out at 80 ◦C at aqueous media. UV-Vis, ...
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Silver nanoparticles (Ag NPs)-reduced graphene oxide was prepared through the in situ nucleation of Ag NPs on reduced, modified GO (rMGO). Glycine was used as a green reducing as well as modifier agent for GO to obtain rMGO. Nucleation of Ag NPs on rMGO was carried out at 80 ◦C at aqueous media. UV-Vis, FT-IR, and XRD techniques confirmed the reduction, modification, and synthesis of Ag NPs. Meanwhile, the morphology of rMGO and rMGO-Ag nanocomposite was investigated with SEM and TEM images. The synthesized nanocomposite showed excellent catalytic behavior for the reduction of 4-nitrophenol (4-NP) by NaBH4. The electrocatalytic behavior of Ag NPs on rMGO for electroreduction of H2O2 was investigated by cyclic voltammetry (CV). In the optimum condition, H2O2 was determined with a detection limit of 9.4 µM and sensitivity of 0.52 µAµM-1. In addition, with the investigation of MIC data of nanocomposite, it was distinguished that this compound has excellent antibacterial activity.
Hamid-Reza Zare-Mehrjardi
Abstract
Acridine orange supported on multi-walled carbon nanotube (MWCNT) is used for modification of carbon-paste electrode. The studies show that acridine orange efficaciously immobilized in the matrix of the electrode by applying nafion/MWCNT composite under the ultrasonic condition. The results of voltammetric ...
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Acridine orange supported on multi-walled carbon nanotube (MWCNT) is used for modification of carbon-paste electrode. The studies show that acridine orange efficaciously immobilized in the matrix of the electrode by applying nafion/MWCNT composite under the ultrasonic condition. The results of voltammetric experiments demonstrate that the prepared electrode has an effective response to DA and AA and a relatively big anodic peak separation (nearly 368 mV) is obtained for these compounds. Good sensitivity and selectivity and very low detection limit (0.03 µM) makes the modified electrode very effective in the manufacture of simple devices for the concurrent detection of dopamine in the presence of ascorbic acid in clinical and pharmaceutical preparations.
Aida Esmati Arze Olia; Javad Feizy
Abstract
In the present study, a novel sorbent-based microextraction method was developed for the quick extraction of ochratoxin A from food samples. The extraction was performed based on graphene-reinforced fabric phase sorptive extraction (FPSE) followed by HPLC-FLD analysis. Chromatographic separations were ...
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In the present study, a novel sorbent-based microextraction method was developed for the quick extraction of ochratoxin A from food samples. The extraction was performed based on graphene-reinforced fabric phase sorptive extraction (FPSE) followed by HPLC-FLD analysis. Chromatographic separations were performed on a C18 column with H2O: ACN: acetic acid (49:49:2, v/v/v) as mobile phase at a flow rate of 1.0 mL/min and with fluorescence detection (λex= 333 nm and λem= 447 nm). The effect of graphene in the sol solution, extraction time, ionic strength, solvent extraction volume, desorption time, and desorption solvent type and volume were evaluated to obtain the maximum extraction efficiency. The optimum condition was obtained at pH=7, 40 mg of graphene per 10 mL of sol solution, 40 min for extraction time and 20 min for desorption time, the best solvent for desorption was 1 mL of ACN: HOAC (95:5 V/V) and extraction volume was 10 mL. The method showed a linear range of 2.0-17.5 ng/mL with a correlation coefficient greater than 0.97. The limit of detection and limit of quantification were found 0.49 ng/g and 1.49 ng/g, respectively with absolute good recoveries (67.7-104.0%) and low relative standard deviations. In addition, ochratoxin A was quantified with the developed method in wheat and chickpea samples and the results indicate the effectiveness of the presented method.
Maryam Akhondi; Daryoush Afzali; Ali Mostafavi
Abstract
In this study, iron oxide/cellulose acetate nanocomposite was prepared by electrospinning method and its performance was evaluated for removal of arsenic. Here, oleic acid coated magnetite nanoparticle was synthesized by co-precipitation method and was impregnated in cellulose acetate solution. This ...
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In this study, iron oxide/cellulose acetate nanocomposite was prepared by electrospinning method and its performance was evaluated for removal of arsenic. Here, oleic acid coated magnetite nanoparticle was synthesized by co-precipitation method and was impregnated in cellulose acetate solution. This magnetite impregnated polymer solution, was electrospun to form nanocomposite polymer fiber. The cellulose acetate/iron oxide nanocomposite membrane was characterized by SEM and FTIR. The magnetic properties of composite nanofibers were characterized by using vibrational sample magnetometry analysis. The nanocomposite was used to remove arsenic ions from aqueous solution. Batch adsorption experiments were carried out to study the sorption behavior of arsenic ions as a function of pH, contact time and initial concentration. Experimental results showed that the maximum capacity of the cellulose acetate-iron oxide nanocomposite membrane for removal of arsenic from low concentration is 0.36 mg/g at pH 9. For better investigation of the adsorption mechanism, two isotherm models, Langmuir and Freundlich were tested. Based on the isothermal results, adsorption data were fitted well to Langmuir isotherm. The reusability of the nanocomposite membrane was confirmed for several adsorption and desorption processes by acid-alkali treatment.
Amir Hossein Saeidnejad; Rooholla Moradi
Abstract
Evaluation of plant responses under different environmental conditions is a principal step towards a better understanding of their function and performance. In this investigation, cumin (Cuminum cyminum), which is known as an important medicinal plant, was examined under three different growing conditions ...
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Evaluation of plant responses under different environmental conditions is a principal step towards a better understanding of their function and performance. In this investigation, cumin (Cuminum cyminum), which is known as an important medicinal plant, was examined under three different growing conditions including natural habitat, field and greenhouse conditions in order to clarify the effects of growing conditions on essential oil properties. Essential oil (EO) content was higher in natural habitat samples, but the composition of EO was varied along the three samples extracted from the above three conditions. Overall, 17 compounds were detected and the key component in all samples was thymol, with the highest amount of 18.03% in natural habitat samples. Cuminaldehyde, γ-terpinene, α-thujene and limonene were other substantial compounds of the EO. Some elements were not detected in all samples such as p-cymene which was not extracted from the EO of natural habitat sample and acetoxylinalool which was not observed in greenhouse sample analysis. Regards to phenol content, natural habitat samples showed the highest amount and the lowest value was obtained on field sample. Radical scavenging activity of EO was also higher in natural habitat samples and with respect to phenolic content analysis, it could be considered as a substantial advantage rather than the others. To sum up, results indicated some advantages of natural habitat samples, although field samples also showed superiority in some parameters.
Hassan Karami; Foroozandeh Taala; Mohammad Ali Karimi; Reza Behjat-Manesh Ardakani
Abstract
In this work, sub-micro and nanometer sized Mg and Mg/carbon composites as anode materials of Mg-air batteries is prepared by using an innovative rotary ball mill. Characterization of the prepared samples is performed by dynamic light scattering, scanning electron microscopy, transmission electron microscopy ...
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In this work, sub-micro and nanometer sized Mg and Mg/carbon composites as anode materials of Mg-air batteries is prepared by using an innovative rotary ball mill. Characterization of the prepared samples is performed by dynamic light scattering, scanning electron microscopy, transmission electron microscopy and, X-ray diffraction techniques. The effects of milling time and amount of carbon additive are evaluated on the sizes of Mg particles in different samples, the discharge capacities and also other electrochemical performances of both primary and secondary magnesium air batteries. An aqueous solution of 2 M Magnesium Chloride and 3 M Sodium Chloride and an organic solution of 0.2 M I2 in Dimethyl Sulfoxide are used as electrolytes in primary and secondary Mg-air batteries, respectively. The Mg sample T6 with average particle size of 170 nm and the Mg/carbon composite sample T13 with average particle size of 35 nm show the highest discharge capacities in both primary (333.1 and 418.6 mA.h g-1) and secondary (354.4 and 433.9 mA.h g-1) Mg-air batteries, respectively. The cycle life test was examined on all constructed rechargeable Mg-air batteries over 30 cycles.
Majid Haji Hosseini
Abstract
The rapid expansion of a supercritical solution (RESS) process has limited commercial applicability due to the extremely low solubility of polar drugs in supercritical CO2 (sc CO2). To overcome this major limitation, a modified process of rapid expansion of supercritical solution with solid cosolvent ...
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The rapid expansion of a supercritical solution (RESS) process has limited commercial applicability due to the extremely low solubility of polar drugs in supercritical CO2 (sc CO2). To overcome this major limitation, a modified process of rapid expansion of supercritical solution with solid cosolvent (RESS-SC) is proposed. Here, the RESS-SC is examined for clozapine using menthol solid as a cosolvent to reduce particle size and to increase drug solubility. In addition, the effect of extraction pressure and extraction temperature was investigated on the size and morphology of precipitated particles of clozapine. The properties of the micronized clozapine were assessed using scanning electron microscopy (SEM) and powder x-ray diffraction (XRD) techniques. In this study, the average particle size of clozapine was reduced from 29.15 (before RESS-SC) to 3.15 μm (after RESS-SC).
Pouran Pourhakkak; Shokoufeh Omidi; Mahdi Yarahmadi
Abstract
In this research, the results of two existing methods for synthesizing gold nanoparticles, i.e., the green and environment-friendly method and the usual chemical method called Turkovich, were compared and analyzed. In the green method, the extract of the aerial parts of the medicinal plant Mentha pulegium ...
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In this research, the results of two existing methods for synthesizing gold nanoparticles, i.e., the green and environment-friendly method and the usual chemical method called Turkovich, were compared and analyzed. In the green method, the extract of the aerial parts of the medicinal plant Mentha pulegium was used as a regenerating agent, and both methods, SEM, TEM, UV-VIS, EDX, and DLS, investigated the properties of the synthesized gold nanoparticles. The results indicated that the green synthesis of gold nanoparticles by extracting the aerial parts of the Mentha pulegium plant was smaller and more stable than the Turkevich method. SEM and TEM results show that the morphology of all nanoparticles is spherical. The size of nanoparticles synthesized by sodium citrate is 10.3 nm, and the size of nanoparticles synthesized by Mentha pulegium plant extract is 9.6 nm. The UV-VIS results show almost absorption in the region of 526 nm for gold nanoparticles synthesized by sodium citrate and absorption in the region of 421 nm for gold nanoparticles synthesized by Mentha pulegium plant extract. The synthesized gold nanoparticles had antibacterial activity against different bacteria.
Mahnaz Ghereghlou; Jalil Afshar; Seyed Hossein Mousavi
Abstract
Measuring preservative concentrations in food is crucial due to their potential health implications. Therefore, it is necessary to develop a reliable and validated analytical method for monitoring. This study focuses on the validation of a simple, sensitive and precise analytical approach using HPLC-DAD ...
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Measuring preservative concentrations in food is crucial due to their potential health implications. Therefore, it is necessary to develop a reliable and validated analytical method for monitoring. This study focuses on the validation of a simple, sensitive and precise analytical approach using HPLC-DAD to concurrently assess sodium benzoate and potassium sorbate. The validation process resulted in exceptional outcomes, demonstrating strong linearity (R2 > 0.999), precision (RSD < 5%), and accuracy (recovery values ranging from 90.77% to 100.55%). Additionally, the method exhibited low limits of detection and quantification (0.8 and 2.65 mg L-1 for sodium benzoate, and 0.14 and 0.47 mg L-1 for potassium sorbate, respectively). The effectiveness of the validated method on different food metrics was shown by analyzing 110 samples of Olivier salad, dairy products and ketchup sauce from Mashhad, Iran. Comparison of the results with Iran's national standards revealed that the preservative concentrations in most samples were within the acceptable limits set by Iranian regulations.
Alireza Mohadesi; Rasool Roohparvar; Nahid Yaghoobi
Abstract
The use of additives is a standard method in both electrowinning and electrorefining of copper. They have multiple roles in the electrodeposition of copper. They are diffusion barriers and/or complexing agents for copper. In addition, they can perform other important roles as well. Thiourea has been ...
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The use of additives is a standard method in both electrowinning and electrorefining of copper. They have multiple roles in the electrodeposition of copper. They are diffusion barriers and/or complexing agents for copper. In addition, they can perform other important roles as well. Thiourea has been extensively used as an additive in industrial copper electrorefining processes. The effect of thiourea on anode passivation, nodule formation in the cathode, and polarization of copper reduction has been investigated. In this study, we reviewed the most important studies conducted on the mechanism of thiourea effect in the copper electrorefining process, as well as the methods of determination and monitoring thiourea in real samples of copper refinery.