Journal of the Iranian Chemical Society最新文献

Supercapacitors are one of the most unique energy storage devices with high efficiency. Supercapacitors are known as renewable sources and replace batteries. This research presents the making of a new generation of supercapacitors in a simple method with high specific capacity and the property of maintaining specific capacity in long and multiple cycles based on polyaniline and carbon cloth fibers with graphene oxide. This nanocomposite is characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, ultraviolet–visible spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and thermogravimetric analysis. The electrode made of this nanocomposite has a specific capacity of 420 F g⁻¹, and after 1000 cycles, it retains more than 83% of the specific capacity, which reaches 348.6 F g⁻¹ at a current density of 1 A g⁻¹. The improvement of retention of specific capacity in the presence of graphene oxide compared to the absence of graphene oxide is more than 10%. This electrode, by maintaining its specific capacity in many cycles, has obtained a significant advantage over other electrodes. These results show that the electrode based on carbon cloth fibers/polyaniline/graphene oxide (CFs/PANI/GO) nanocomposite can be a high-performance and environmentally friendly electrode.

The Pt/HZSM-5-(KCC-1, KIT-6, and SBA-3) catalysts were successfully used for the isomerization reaction of n-heptane. These catalysts were used to optimize this process at response surface methodology combined with central composite design. The effects of temperature, contact time, and flow rates of n-heptane and hydrogen, as some important variables, on the response (reaction rate) were studied. The analysis of variance gave a significant quartic model with good accuracy for estimating the reaction rates for these catalysts. The optimum conditions were obtained for the Pt/HZSM-5-SBA-3 catalyst at a temperature of 350 °C, contact time of 6 h, an H₂ flow rate of 20 cc min⁻¹ and an n-C₇ flow rate of 2 cc h⁻¹ with a reaction rate of 5.7 mol g⁻¹s⁻¹. The modeling results also showed that both the power law and Langmuir–Hinshelwood models agreed with the data obtained from catalytic performance (R² > 0.9). The results show that the Pt/HZSM-5-SBA-3 catalyst has the lowest activation energy (13.64 kJ mol⁻¹) and the highest reaction rate. The reaction order for hydrogen is in the range of − 0.03 to − 0.25 and that for n-C₇ is 0.88–1.19.

This study aimed to enhance the permeability and antifouling properties of the polymer membrane of polyethersulfone (PES) through the modification with TiO₂–AgBr–Ag–SBA-15. The hydrothermal process is used to create silica nanoparticles (SBA-15), which involved the use of tetraethylorthosilicate as a precursor and a copolymer Pluronic P123 (as a mold and the structure maintainer after solvent exiting). Then, SBA-15 nanoparticles are added to the preparation solution of TiO₂–AgBr–Ag, resulting doping nanoparticles (TiO₂–AgBr–Ag–SBA-15) were incorporated into the casting solution to achieve weight percentages of 0.4, 0.6, 0.8 and 1 in the final membranes. The nanoparticles were characterized using FESEM, FT-IR, XRD, XPS and EDX. Meanwhile, the membrane properties were studied using FESEM, FT-IR, CA, AFM and membrane performance tests. The hybrid membranes exhibited a less hydrophobic surface, which consequently resulted in water permeability. Moreover, the antifouling properties were notably improved, resulting in a considerable improvement in permeability without compromising the membrane's ability to remove unwanted substances. At 3.5 bar pressure, the pure water flux of the 0.8 wt% PES/TiO₂–AgBr–Ag–SBA-15 membrane was two times higher than that of the pristine membrane. Flux recovery rate of 1 wt% PES/TiO₂–AgBr–Ag–SBA-15 membrane can reach 90%, and the antifouling performance is excellent.

This work presents a comprehensive study of the UV–Visible and fluorescence properties, as well as the redox behavior of the [Au^III(Salen)]Cl complex in acetonitrile. The [Au^III(Salen)]⁺ complex exhibited intriguing fluorescence and phosphorescence characteristics on an indium tin oxide (ITO)-coated glass plate when excited at wavelength λ_exc ~ 260 nm, with fluorescence emission observed at λ_ems ~ 437 nm and phosphorescence at λ_ems ~ 520 nm. The origin of fluorescence emission was attributed to the intra-ligand charge transfer effect, commonly known as the "Push–Pull" effect. The electrochemical behavior of [Au^III(Salen)]⁺ on a glassy carbon electrode (GCE) revealed a remarkable one-step three-electron reduction process, leading to the reduction of [Au^III(Salen)]⁺ to Au(0). Furthermore, the reduction of [Au^I(Salen)]⁻ to Au(0) resulted in the removal of gold metal from the SalenH2 ligand. The electrochemical results suggested a mixed diffusion-adsorption redox process occurring at the GCE surface, indicating the involvement of both diffusion and adsorption during redox reactions. The cyclic voltammogram demonstrated the non-reversibility of the electrochemical redox reactions. Overall, the redox behavior of the [Au^III(Salen)]Cl complex proved to be intriguing, opening up avenues for further exploration and potential applications of this complex in various fields.

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This study involves the preparation of sodium alginate poly grafted (fumaric acid-polyacrylic acid)/graphene oxide, SA-g-p(FA-AA)/GO hydrogel to explore its potential as a promising adsorbent for water treatment mainly chromium (VI) and lead (II) removal. Prepared adsorbent was characterized by FTIR, TGA, XRD, FESEM, and TEM techniques for exploring the chemical structure, thermal stability, crystallography, surface area and morphology, as well as pore size and distribution of SA-g-p(FA-AA)/GO, respectively. The average size of the prepared nanoparticles was observed to be 78.48 nm. The TEM images exhibit a predominantly spherical shape and heterogeneous. Effect of different physiochemical parameters such as pH, temperature, adsorbent dosage, and contact time was explored for maximum metal adsorption. The results of the study revealed that the maximum adsorption capacity of SA-g-p(FA-AA)/GO (0.045 mg g⁻¹ for Cr (VI) and 22.371 mg g⁻¹ for Pb (II)) was achieved under optimized conditions, i.e., adsorbent dose of 0.05 g at 25 °C for pH of 2, 4.5 when contact time of 5 and 100 min was used for Cr(VI) and Pb(II), respectively. Data fits best to the pseudo-second-order kinetic equation revealing the multilayer adsorption of Cr (VI) and Pb (II) ions on the heterogeneous adsorbent surface. Thermodynamically, the process of Cr (VI) and Pb (II) adsorption was non-spontaneous, exothermic and feasible revealing the potential of the prepared adsorbent to be used as an efficient adsorbent for metal removal.

The catalytic efficacy of ruthenium (Ru)-exchanged montmorillonite, a well-established heterogeneous catalyst, was systematically explored to synthesize diverse bis(indolyl)methanes. The developed methodology consistently yielded the desired products with satisfactory to excellent yields, while notable advantages of the proposed approach encompassed minimal reaction times and solvent-free conditions. Furthermore, the method was characterized by its procedural simplicity, facile catalyst synthesis, ready accessibility of the starting materials from commercial sources, and the potential for catalyst recyclability.

In this research, a Fe₃O₄/Al₂O₃/CuO magnetic nanocomposite (NC) was prepared by co-precipitation method for photocatalytic activity and identified using VSM, TEM, FE-SEM, EDX, XRD and DRS techniques. Based on the TEM analysis, the structure of NC was observed as nanorods. Also, the presence of CuO was confirmed by EDX and XRD analyses. Using the DRS spectrum results, the energy band gap of Fe₃O₄/Al₂O₃/CuO NC was determined as ~ 2 eV. The synthesized compound was used as a photocatalyst for the degradation of methylene blue under sunlight irradiation. The reaction process was investigated by ultraviolet–visible spectroscopy. According to the obtained results from MB degradation about 95 percent of MB (10 mg/L) was decomposed after 25 min under sunlight irradiation. Furthermore, even after five cycles, the rate of MB degradation could still exceed 90 percent. Also, based on the obtained results, the synthesized NC can be recovered and reused in the photochemistry process. Additionally, based on the results, the Fe₃O₄/Al₂O₃/CuO NCs show high performance photocatalytic activity toward the degradation of MB under solar radiation.

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In the present study, the integration of magnetic dispersive micro-solid-phase extraction (MD-µSPE) with hollow fiber liquid-phase microextraction (HF-LPME) prior to gas chromatography–mass spectrometry (GC/MS) was developed to preconcentrate and determine trace amounts of chlorpyrifos pesticide. Azolla filiculoides fern biomass was loaded by magnetite nanoparticles to prepare magnetic adsorbent (azolla@Fe₃O₄). The structural characteristics of the produced magnetic nanocomposites (MNCs) were investigated by FESEM, TEM, VSM, FTIR, EDX, and XRD methods. In the proposed MD-µSPE/HF-LPME method, the adsorption/desorption variables in MD-µSPE step were optimized by Taguchi fractional factorial design. After chlorpyrifos adsorption in the optimized condition of MD-µSPE (V_sample = 50 mL, contact time = 15 min, solution pH = 3, adsorbent mass = 0.05 g, ionic strength = 0.01 mol L⁻¹, and eluent type = ethanol), 2.0 mL of the desorbed ethanolic solution was added to 16 mL of 10% (w/v) NaCl aqueous solution for the next HF-LPME method and the final analysis was performed by GC/MS. The developed method showed a limit of detection of 0.05 μg L⁻¹, a limit of quantification of 0.5 μg L⁻¹, a dynamic linear range of 0.5–1000.0 μg L⁻¹, preconcentration factors between 700 and 1050, and a repeatability (RSD%) of 6.9%. The suitability of the MD-µSPE/HF-LPME method was confirmed by measuring chlorpyrifos in real samples with relative recoveries in the range of 97.0–108.5%. The results showed good accuracy and precision of the developed MD-µSPE/HF-LPME method for the preconcentration and determination of trace amounts of chlorpyrifos in the aqueous samples.

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Graphene oxide-activated carbon (GO–AC) composite with different ratios of GO and AC (0.5/0.5, 0.3/0.7 and 0.1/0.9) were synthesized via direct chemical bonding of them using hydrogen peroxide as a chemical linker and used for selective removal of diclofenac sodium (DCF) and ibuprofen (IBP) from aqueous solutions. The adsorbents' surface morphology, composition, and physicochemical structure of the adsorbents were characterized by FE-SEM, FTIR, BET and XRD analysis. The synthesized composite with a ratio of GO and AC (0.1/0.9) was the most suitable among the synthesized adsorbents for both DCF and IBP adsorption. The optimal working conditions for DCF removal were at pH of 2, contact time of 40 min, initial concentration of 100 mg/L, and temperature of 293 K. For IBP removal, the optimal operating conditions were at pH of 2, contact time of 60 min, initial concentration of 20 mg/L, and temperature of 293 K. The highest adsorption capacities of 0.1/0.9 composite for DCF and IBP were 833.33 and 238.095 mg/g at 298 K, respectively. Isotherm, kinetic, and thermodynamic characteristics were assessed to analyze the adsorption process. The synthesized adsorbent displays high removal efficiency by simple recyclability with low-cost reagent and high selectivity for drug pollutants such as DCF and IBP in single and binary systems.