Journal of the Iranian Chemical Society最新文献

Bio-adsorbents with high adsorption efficiency, sustainability, and reusability are desired in wastewater treatments. Herein, a covalently cross-linked green macroparticle hydrogel biocomposite (AM-AC/CMC-Ca) as a bio-adsorbent was prepared through an acrylamide (AM) reaction with a polysaccharide carboxymethyl cellulose (CMC)-modified activated carbon (AC) and further Ca(II) cross-linking polymerization, with efficient removal of Safranin T (ST) cationic dye. FESFM/EDX, XRD, FTIR, BET, and TGA were used to limit the structure and characteristics of the biocomposite. The effects of the concentration for both AM, CMC, AC, and Ca(II) cross-linked on swelling behavior were studied, which yielded that the maximum swelling ratio (SR%) in distilled water was 3500%. The ST dye adsorption capacity was evaluated, and the results illustrated that (AM-AC/CMC-Ca) biocomposite prepared under the optimized conditions displays a super strong adsorption efficiency of 1558.52 mg/g and almost 100% removal efficiency within 1 h adsorption time at pH 7.6 and 25 °C. They decrease slightly with the decrease in pH 3, and the zero-point charge was determined to be 4.2. The pseudo-first-order, pseudo-second-order, chemisorption, and intra-particle diffusion kinetic models were useful to test the experimental result, the second order exhibited the best fit for the kinetic studies. The equilibrium result was assessed using the Freundlich, Langmuir, and Fritz–Schlender isotherm model, and the Freundlich isotherm best refers to the uptake of ST dye, which suggests that the adsorption of dye in this study onto biocomposite is heterogeneous with multilayers. Thermodynamic parameters indicated that the adsorption of ST dye onto the biocomposite was spontaneous (ΔG < 0), and endothermic (ΔH > 0). Additionally, the biocomposite showed high reusability and regeneration, maintaining an 88.8% removal capacity for ST dye after 6 cycles.

Nanosized materials are increasingly being recognized as inherent components in the development of energy storage devices and other state-of-the-art dielectric applications. In this work, nickel oxide (NiO), cobalt oxide (Co₃O₄) and NiO–Co₃O₄ nanocomposites in different compositions (10%, 20%, 30% and 40%) were successfully synthesized through hydrothermal method, optimizing concentrations of the precursors, and X-ray diffraction confirmed single-phase polycrystalline NiO and Co₃O₄. SEM images showed that distinct morphologies for each material and FTIR spectra reveal Ni–O and Co–O. UV–visible analysis shows a plasmon peak at 307 nm for NiO and excition absorption at 282 nm for Co₃O_4. NiO–Co₃O₄ nanocomposites displayed band gaps ranging from 2.37 eV to 2.67 eV. Dielectric properties showed a decrease in εʹ with frequency, attributed to Maxwell–Wagner and hopping models. AC conductivity increased with frequency due to Co₃O₄ content and oxygen vacancies. The study suggests potential applications in supercapacitors, spintronics, high-frequency devices and ultra-high dielectric materials.

The development of hydrogen fuel vehicles is a critical issue in the face of increasing energy demands, depletion of fossil fuels, and the urgent need to reduce greenhouse gas emissions. Hydrogen, as a clean energy carrier, holds great promise for zero-emission vehicles. Magnesium hydride (MgH₂) is considered a promising material for hydrogen storage due to its high storage capacity (7.6 wt% and 102 g/L) and non-toxic nature. However, its practical application is limited by slow hydrogen sorption kinetics and thermodynamic stability. This study hypothesizes that adding copper oxide nanoparticles (CuO-nano) supported on high surface area activated carbon (AC) can enhance the sorption properties of MgH₂. AC derived from jute waste was used as a promoter in the ball-milled AC/MgH₂/CuO composite. The results from thermogravimetric analysis (TGA) indicate significant improvements in hydrogen adsorption and desorption rates at standard temperature and pressure. According to TGA analysis the dehydrogenation onset temperature of the ball-milled composite decreased significantly from 400 (fresh MgH₂) to 250 °C with the AC/CuO additive. The AC/MgH₂/CuO (AMC) composite sample exhibited a hydrogen desorption rate of 90% within 10 min at 250 °C. These findings suggest that the addition of AC/CuO effectively enhances hydrogen adsorption and desorption performance. This finding opens a new pathway for the development of efficient hydrogen storage materials.

Thiamine detection has been developed using Copper-Metal Organic Frameworks (CuMOF) and Rhodamine B-complexed Graphene Oxide (RhGO), facilitating both direct and indirect fluorescence-based sensing of thiamine. Both these methods are less cumbersome and sensitive fluorometric methods which are developed from less expensive materials. CuMOF offered the oxidation route of thiamine to thiochrome, which is a fluorescence compound; through which thiamine was detected conveniently by measuring thiochrome. On the other hand, rhodamine B bound graphene oxide–RhGO, released rhodamine B upon interaction with the thiamine through the competitive binding against the rhodamine B located on the graphene oxide, which allowed us to develop a facile sensor for thiamine in DMF. Moreover, the sensitivity of the sensor was improved through the encapsulation effect with cucurbit[7]uril (CB[7]). The limits of detection (LOD) for CuMOF and RhGO with CB[7] were determined to be 48.39 × 10^–8 M and 68.33 × 10^–8 M, respectively. The sensing ability of RhGO was effectively utilized in commercially available thiamine drugs, and its performance was evaluated against other hydrochloride drugs such as metformin, ciprofloxacin, and cetirizine demonstrating its suitability for real-time sample analysis. This approach provides a practical solution for both analytical and pharmaceutical laboratories. Overall, two different detection methods for thiamine have been developed with good selectivity and sensitivity.

Graphical Abstract

A method for the analysis of trace nitrogen trifluoride impurities in high-purity carbon tetrafluoride (≥ 99.999%) by gas chromatography equipped with a flame ionization detector is described. A 10-port valve and three columns have been used in this instrument system, which can completely separate nitrogen trifluoride and carbon tetrafluoride. In the best analytical conditions, the quantification limit was estimated at 16.62 ppb for an injected sample volume of 1 mL. Furthermore, this method can be completed by one sample injection without the need to vent some of the main component-high-purity carbon tetrafluoride through the valve switch, which is more accurate and simple.

In this study, the catalytic activity of an oxovanadium(IV) unsymmetrical salophen complex immobilized on chloro-functionalized silica-coated CoFe₂O₄ magnetic nanoparticles CoFe₂O₄@SiO₂@CPTMS@VO(salophen-OH), in which salophen-OH = 4-[(E)-{(2-[(E)-2-hydroxybenzylidene)amino]phenyl}imino)methyl]benzene-1,3-diol was explored in the oxidation of alcohols and hydrocarbons. This heterogeneous nanocatalyst showed high activity and selectivity in oxidizing various primary and secondary alcohols to the equivalent aldehydes and ketones with 30% H₂O₂ as a green oxidant in polyethylene glycol (PEG) as an eco-friendly solvent at 80 °C. Furthermore, the above catalyst demonstrated significant catalytic efficiency in the alkene epoxidation and alkane hydroxylation using tert-butyl hydroperoxide (tert-BuOOH), and the corresponding products were achieved in good to excellent yields in acetonitrile at ambient temperature. This magnetic nanocatalyst can be easily separated from the reaction mixture utilizing an external magnet and reused up to five times without significant activity loss. Moreover, the recovered catalyst’s structure was scrutinized using Fourier transform infrared (FT-IR), vibrating sample magnetometry (VSM), and X-ray diffraction (XRD) techniques, which confirmed that the structure of the catalyst remained unaltered post-recovery.

Two new complexes of europium (III) and erbium (III) were synthesized from diaminodiphenylether bridged spacer in 1:1 molar ratio of ligand and metal salt, whereas the ligand was synthesized in 1:2 molar ratio of diaminodiphenylether and aldehyde. The synthesized complexes were structurally analyzed through nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), energy-dispersive X-ray diffraction (EDX), UV–visible and photoluminescence spectroscopy. In both synthesized complexes, the metals were found in coordination to nitrogen and oxygen atoms of the azomethine (HC = N) and hydroxyl (–OH) groups as evident by FTIR and NMR spectral results in both synthesized complexes. Molar conductivity data for Eu(III) and Er(III) observed in the range of 129–135.5 Ω⁻¹cm² mol⁻¹ determined that both complexes were 1:2 electrolytes. The presence of characteristic peaks for Eu, C, O and N was clearly identified in energy-dispersive X-ray diffraction, which confirmed its successful synthesis. Furthermore, the luminescence behavior of the complexes was investigated in the solution state with dichloromethane (DCM). Upon excitation at 274 nm, both complexes exhibited two emission bands centered at 379 nm to 399 nm and 519 nm for Eu(III) and Er(III). Consequently, the good emission properties illustrated that the synthesized complexes featured their potential as promising cost-effective luminescent materials.

Graphical abstract

By considering the importance of heterogeneous catalysts with separation and recycling ability from the reaction environment and ring opening of epoxide as a regularly essential conversion in organic synthesis, tetraaza macrocyclic complexes of Cu(П), Fe(IП) and Cr(Ш) were grafted on the acylated multiwalled carbon nanotubes (MWCNTs) to produce new nanocomposites as heterogeneous catalysts. Then the nanocomposites were applied in the regioselective ring-opening reaction of epoxystyrene with different alcohols to obtain β-alkoxy compounds. For the characterization of tetraazamacrocycle and nanocomposites, FT-IR, TGA, XRD, FE-SEM and Raman were employed. Results showed that the complexes were successfully grafted on the functionalized MWCNTs. Ring-opening reactions took place at high yield and favorite time, especially for the shorter chain alcohols. In the best case, nanocomposite containing Fe(Ш) (MWCNTs-C (=O)–TAM·Fe^III) accomplished the ring opening of epoxystyrene by methanol (100%) within 15 min at 50 °C, and after 3 recycling test, there are negligible changes in its catalytic performance.

Until now, there have been many reports on the regulation of inorganic metal ions on the catalytic activity of nanozymes, but few reports on the regulation of anions (such as NO₂⁻) on enzyme activity. In this work, a copper-molybdenum doped carbon dots (Cu, Mo-CDs) with peroxidase-like (POD) activity was synthesized by simple one-step microwave digestion method. The Cu, Mo-CDs + NO₂⁻ system can promote 3,3′,5,5′-tetramethylbenzidine (TMB) oxidizing to blue oxidative product (oxTMB) due to the formation of ∙NO₂ free radical. While Hg²⁺ was introduced into the system, the POD-like activity of Cu, Mo-CDs + NO₂⁻ system was inhibited due to the strong interaction and the electron transfer between Cu, Mo-CDs and Hg²⁺. The formation of ∙NO₂ and the electron transfer capability of Cu, Mo-CDs + Hg²⁺ were confirmed through ESR spectra and FMN experiments. The bioenzyme-free colorimetric assay based on Cu, Mo-CDs nanozyme is used for detection of NO₂⁻ and Hg²⁺, showing lower detection limit (LOD) of 1.63 µg/L for NO₂⁻, 0.13 µg/L for Hg²⁺, respectively and good recovery from 90.79 to 108.90%. The work paves a new way to design a nanozyme-based colorimetric protocol for traces NO₂⁻ and Hg²⁺ residues in food analysis.