کاربردهای شیمی تجزیه
Mehdi Hosseini; Ebba Adnan Azooz
Abstract
The process of interesterification is one of the most important alternative ways of hydrogenating oils, which is of particular importance by providing the possibility of changing the functional, physical and chemical properties of oils in a favorable way. In this work, a pyrrolidinium-based acidic ionic ...
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The process of interesterification is one of the most important alternative ways of hydrogenating oils, which is of particular importance by providing the possibility of changing the functional, physical and chemical properties of oils in a favorable way. In this work, a pyrrolidinium-based acidic ionic liquid, N-methylpyrrolidinium bisulfate ([Mpyr][HSO4]), was synthesized and characterized, and its catalytic performance was evaluated in the interesterification (glycerolysis) of triglyceride oils. Common analyzing techniques such as Fourier Transfer Infra-red (FTIR) and Nuclear Magnetic Resonance (NMR) techniques were used to catalyst characterization, structure and different bonds evaluation in catalyst structure. The catalytic activity of [Mpyr][ HSO4] during interesterification process of soy oil as raw material of triglycerides and glycerol reagents was investigated. For evaluation of interesterification procedure, the effects of several important parameters such as reaction time and temperature, molar ratio of oil: glycerol and catalyst dosage were investigated. The results obtain showed that the catalyst of [Mpyr][HSO4] is suitable for the interesterification (glycerolysis) of triglyceride oils and it has a conversion of about 97.5%. A simple and accurate titration method was used to evaluate the rate raw materials conversion into ester. Furthermore, in order to reuse the catalyst, the catalyst can be reused up to seven times.
کاربردهای شیمی تجزیه
Negar Gholhovallahi; Ali Sheibani
Abstract
Ion mobility spectrometry is an analytical technique with main advantages such as high sensitivity, fast response and simplicity. The purpose of this work was to determine of mesalazine in different pharmaceutical samples using ion mobility spectrometry with a positive corona ionization source. After ...
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Ion mobility spectrometry is an analytical technique with main advantages such as high sensitivity, fast response and simplicity. The purpose of this work was to determine of mesalazine in different pharmaceutical samples using ion mobility spectrometry with a positive corona ionization source. After obtaining the best instrumental parameters (injection temperature: 230 ºC, cell temperature: 180 ºC, drift voltage: 6800 V, corona voltage: 2400 V, flow rate of drift gas: 600 mL/min and flow rate of carrier gas: 300 mL/min) the linear dynamic range was 1.0–70.0 ng with a determination coefficient, R2=0.9881. The relative standard deviation values were lower than 6.0% (n=5) for the examined range (10.0–60.0 ng) of the drug. The limit of detection and limit of quantitation were 0.3 ng and 1.0 ng, respectively. The capability of the developed method was evaluated for the determination of mesalazine in tablet, capsule, and suppository as pharmaceutical samples. Satisfactory recovery results were obtained in the range of 98.0–103.8%.
کاربردهای شیمی تجزیه
Mohammad Radi; Ensie Bekhradinassab
Abstract
In this study, the catalytic performance of commercial molecular sieves (MS) was enhanced through a systematic acid modification process using hydrochloric acid (HCl) at varying molar concentrations (0.25, 0.5, and 1.0 M). The influence of acid strength on the structural, morphological, and elemental ...
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In this study, the catalytic performance of commercial molecular sieves (MS) was enhanced through a systematic acid modification process using hydrochloric acid (HCl) at varying molar concentrations (0.25, 0.5, and 1.0 M). The influence of acid strength on the structural, morphological, and elemental properties of the catalysts was rigorously evaluated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDX). Analytical results revealed that acid treatment facilitated the selective removal of extra-framework cations and induced framework dealumination, effectively modulating the Si/Al ratio and increasing surface acidity. The EDX analysis suggested an optimal Si/Al ratio of 4.5 for the 0.5 M HCl-treated sample, which maintained framework integrity while maximizing active site accessibility. The catalytic efficiency was assessed through the esterification of oleic acid for biodiesel production. The MS-0.5 M catalyst exhibited superior performance, achieving a free fatty acid (FFA) conversion of 87.57% under optimized reaction conditions (methanol-to-oil ratio of 20:1, 3 wt% catalyst, and 95 °C). In contrast, higher acid concentrations (1.0 M) resulted in structural degradation and a subsequent decline in catalytic activity. This study demonstrates that precisely controlled acid modification is a robust analytical approach for developing high-performance, stable, and cost-effective heterogeneous catalysts for sustainable biofuel synthesis.
کاربردهای شیمی تجزیه
Farzaneh Marahel; Seyed Mehdi Dardari; Zohreh Saadati; Marjan Sheibani
Abstract
This study explores the potential of shrimp shell-derived biochar@starch/CoFe2O4NPs for heavy metals and toxic pollutants removal from aqueous environments. The adsorption of Cd(II) ion was studied under the various conditions, including pH, time, adsorbent dose, and temperature. The adsorption process ...
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This study explores the potential of shrimp shell-derived biochar@starch/CoFe2O4NPs for heavy metals and toxic pollutants removal from aqueous environments. The adsorption of Cd(II) ion was studied under the various conditions, including pH, time, adsorbent dose, and temperature. The adsorption process was best described by the Langmuir isotherm and pseudo-second-order kinetic models, indicating monolayer adsorption and chemisorption-dominated interactions. The maximum adsorption capacity was determined to be 56.6 mgg-1 at 298 °K. Thermodynamic results indicated that the process was spontaneous and exothermic. The calculated thermodynamic parameters, such as ΔG°, ΔH° and ΔS° for Cd(II) ion uptake on the adsorbent surface, come out to be -3.45 kJ mol-1, -17.06 kJ mol-1 and -41.26 J mol-1. K-1, respectively. The removal efficiency Cd(II) ion from actual water samples higher reached 90.0 %, although the efficiency decreased with increasing salt concentration. These findings demonstrate that shrimp shell-derived biochar modified with starch/CoFe2O4NPs is a sustainable, low-cost, and environmentally friendly adsorbent with significant potential for Cd(II) ion remediation in contaminated water systems.
کاربردهای شیمی تجزیه
Mohammad Bagi; Masoumeh Tabatabaee; Ali Sheibani
Abstract
Fluoride impurities in industrial zinc sulfate electrolytes adversely affect the zinc electrowinning process by promoting zinc deposition on the aluminum cathode, thereby reducing process efficiency and product quality. In the present study, zirconium oxide (ZrO2) has been used as an adsorbent to remove ...
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Fluoride impurities in industrial zinc sulfate electrolytes adversely affect the zinc electrowinning process by promoting zinc deposition on the aluminum cathode, thereby reducing process efficiency and product quality. In the present study, zirconium oxide (ZrO2) has been used as an adsorbent to remove fluoride of zinc sulfate solution during the industrial electrolysis process of zinc production. The effects of five operational parameters, including ZrO2 dosage, temperature, contact time, stirring speed and pH were systematically evaluated to optimize the fluoride removal process. The initial concentrations of zinc sulfate and fluoride in the electrolyte were 210 g/L and 453 mg/L (ppm), respectively. Under the optimum operating conditions (ZrO2 dosage of 2.0 g/L, temperature of 90 °C, contact time of 20 min, stirring speed of 200 rpm, and also pH 7), more than 90% of the fluoride was removed from the zinc sulfate electrolyte. Moreover, under industrial operating conditions demonstrated that the fluoride concentration could be reduced to below 55 mg/L (adsorption capacity=200 mg/g), significantly alleviating operational problems associated with zinc electrowinning. These findings demonstrate that ZrO2 nanopowder is an efficient and practical adsorbent for fluoride removal from industrial zinc sulfate electrolytes and has considerable potential for industrial application.
کاربردهای شیمی تجزیه
Roostam Jamali Eslami; Mehdi Hosseini
Abstract
Hot springs are natural geothermal systems enriched with dissolved minerals and nano/micro-sized particles that may contribute to their traditional therapeutic properties. In the present study, mineral nanoparticles (MNPs) were isolated for the first time from the Baktar hot spring located in western ...
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Hot springs are natural geothermal systems enriched with dissolved minerals and nano/micro-sized particles that may contribute to their traditional therapeutic properties. In the present study, mineral nanoparticles (MNPs) were isolated for the first time from the Baktar hot spring located in western Iran, and their physicochemical characteristics as well as antibacterial activity were investigated. Structural analyses using FTIR, XRD, XRF, ICP-MS, and TGA revealed that the particles mainly consist of silicate- and metal oxide-based minerals containing high levels of SiO2 (54.07%), Al2O3 (15.2%), CaO (7.19%), and Fe2O3 (5.45%). ICP-MS analysis also demonstrated the presence of several trace and heavy metals, including Sr (685.9 ppm), V (139 ppm), Cr (105 ppm), Zn (85 ppm), and Cu (63 ppm). XRD analysis estimated an average crystallite size of approximately 49.7 nm. The antibacterial activities of heated and unheated MNPs were evaluated against Staphylococcus aureus ATCC 43300 and Pseudomonas aeruginosa using disk diffusion and minimum inhibitory concentration (MIC) assays. The inhibition zone diameter for unheated MNPs reached 19.0 ± 0.50 mm against P. aeruginosa, whereas lower activity was observed against S. aureus (9.32 ± 0.15 mm). Both heated and unheated particles exhibited an identical minimum inhibitory concentration (MIC) of 150 μg/mL. The results suggest that naturally occurring mineral nanoparticles isolated from the Baktar hot spring possess promising antibacterial properties, supporting the potential role of geothermal mineral systems in balneotherapy and biomedical applications. This study represents the first comprehensive analytical investigation of naturally occurring mineral nanoparticles isolated from the Baktar hot spring and provides new insights into the relationship between their elemental composition, physicochemical characteristics, and antibacterial properties.
