Chemical Papers最新文献

In this study, tin oxide based-dispersive solid-phase extraction (SnO₂-DSPE) method followed by flame atomic absorption spectrophotometry (FAAS) was developed for the extraction and sensitive determination of copper at trace levels in domestic and synthetic wastewater samples. Several important parameters including pH and buffer solution volume, adsorbent amount, sample volume, mixing type/period, eluent concentration/volume were optimized to obtain high signal-to-noise ratio and extraction yield for the analyte. Under the optimum SnO₂-DSPE-FAAS conditions, a 45-fold enhancement in detection power of conventional FAAS system was achieved by the developed method. Limit of detection (LOD) and limit of quantification (LOQ) values were calculated as 2.9 and 9.6 µg/L, respectively. Recovery experiments were carried out on the spiked domestic and synthetic wastewater samples in order to control the applicability of the developed method. Excellent percent recovery results (74.8–113.3%) were attained for the spiked samples. According to these results, SnO₂ nanoparticles synthesized by microwave-assisted method can be used as sorbent material for the preconcentration of copper at trace levels. To the best our knowledge, this is the first study for the preconcentration of copper in wastewater samples by SnO₂-DSPE method.

With their global widespread adoption, smartphones have appeared as optimum platforms for standalone sensors, due to having both optical and electrochemical sensing capabilities and other inherent functionalities such as having integrated software, enabling on-site or real-time analysis, in a cost- and time-efficient manner. In this review, we covered studies reporting the recent advances in the use of smartphones in the development of colorimetric, fluorimetric, and electrochemical sensing systems for the analysis of diverse ionic species. We mentioned materials and reagents used in the design of these sensors, their working mechanisms, the instrumentation and data processing systems, their particular analytical performance parameters such as detection limit, and their implementation to the analysis of real samples, highlighting the main recent advances in the field, and also particular advantages, disadvantages and limitations associated with these sensors developed based on smartphone technology.

Researchers are looking into alternate energy sources due to the exhaustion of fossil fuels, energy crisis, and environmental challenges, although supercapacitors (S_c) are promising energy storage devices due to their efficient specific capacitance (C_s), extended cycle life, and enhanced power delivery. The NiMnO₃ and Mo-doped NiMnO₃ electrode material was successfully created using a practical and effective hydrothermal process. The physical characterization of Mo-doped NiMnO₃ demonstrated that Mo doping altered the shape of NiMnO₃ material. Electrochemical investigation of Mo-doped NiMnO₃ exhibited substantial C_s of 684 F/g obtained at current density (C_d) of 1 A/g. The observed outcomes demonstrate an energy density (E_d) value of 11.11 Wh/kg, a significant increase in ion diffusion efficiency, and outstanding power density (P_d) of 171 W/kg at 1 A/g. Furthermore, fabricated Mo-doped NiMnO₃ exhibited low impedance and remarkable 50-h cycling stability after 2500th cycles. The exceptional specific capacitance and extended cycle life of Mo-doped NiMnO₃ electrodes make it a potential material for next-generation supercapacitors.

The sulfate radical anion (SO₄^●–)-initiated oxidation of the herbicide metazachlor (MTZ) was investigated in aqueous and gaseous phases using the density functional theory at the M06-2X/6-311++G(3df,3pd)//M06-2X/6-31+G(d,p) level of theory. Three oxidation mechanisms, including abstraction (Abs), addition (Add), and single electron transfer (SET), were explored to elucidate mechanisms and kinetics. Most oxidation reactions were thermodynamically favorable and spontaneous in Both phases. The overall rate constant at 298.15 K was significantly higher in the gas phase (1.51 × 10¹³ M⁻¹ s⁻¹) compared to water (4.50 × 10¹⁰ M⁻¹ s⁻¹). In water, the degradation process was non-selective, involving various Add and Abs-reactions with similar apparent rate constants k_app ranging from 2.34 × 10⁹ to 2.53 × 10⁹ M⁻¹ s⁻¹ and corresponding branching ratio (Γ) being between 5.20 and 5.63%. In contrast, the gas-phase degradation was highly selective, with the Abs-H24 pathway showing the highest rate (1.08 × 10¹³ M⁻¹ s⁻¹ of k_app and 71.76% of Γ). Temperature-dependent analysis revealed that reaction rates increased with temperature in water (283–323 K), extending MTZ lifetimes from microseconds to hours, but decreased in the gas phase (253–323 K). Notably, abstraction reactions involving methyl and methylene groups predominantly followed a proton-coupled electron transfer mechanism. Ecotoxicology predictions indicate that degradation products from Add reactions exhibit reduced acute and chronic toxicity, as well as lower bioaccumulation, developmental, and mutagenic potential compared to MTZ. These findings highlight the efficacy and potential of SO₄^●–—based advanced oxidation processes for MTZ removal across different phases.

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The SO₄^●– degradation of metazachlor is highly efficient, with rapid rates in gas and water but follows distinct temperature-dependent mechanisms.

The environmental contamination through heavy metals has been considered to be a serious concern among researchers due to its far-reaching impact toward the environment. Among other heavy metals, cadmium in water is considered a perilous environmental challenge due to its persistence and toxicity, necessitating a cost-effective remediation approach. The adsorption of cadmium using cellulose-based biopolymeric beads was investigated in the current study. The cellulose has been derived from rich husk; a promising source of natural polymer due to its chemical composition. This study integrated both the batch adsorption studies and artificial neural network (ANN) for enhanced prediction and accuracy. The structural and chemical behavior of the prepared biosorbent has been characterized through SEM, FTIR, and EDX analysis. The optimum parameters identified from the batch studies include pH = 6.0, adsorbent dosage = 2.5 g/L, contact time = 50 min, temperature = 303 K, and initial cadmium concentration = 1 mg/L. The Langmuir model is the best fit with a q_e of 154.24 mg/g, while kinetic studies specified pseudo-second order with an R² value of 0.9688. The thermodynamic study revealed that the process is exothermic and spontaneous. The ANN model has demonstrated strong prediction accuracy with an R² of 0.9941. The study revealed a higher desorption capacity of 94.57% for HNO₃. The regeneration study states that the adsorption–desorption efficiency has declined after the 4th cycle. These findings highlight rice husk as an efficient and sustainable source for cadmium removal, presenting a solution for addressing heavy metal pollution in wastewater treatment.

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Synthetic plasticizers are endocrine disruptors found in most consumer products, including cosmetics, that disrupt the functioning of the endocrine systems, and phthalates are a key one. The globe is looking for substitutes for these phthalates due to their adverse effects. Therefore, the present study aimed to develop an alternative to phthalates using biopolymers. The combination of naturally derived polysaccharides and a non-ionic surfactant (Tween) was identified as an alternative for phthalate as it exhibited gelling and surface-active properties, which are the essential properties of a plasticizer. The various concentrations of both the polysaccharides (sodium alginates and gellan gum), cross-linking agent (CaCl₂), and the non-ionic surfactant (Tween 80) were screened based on the viscosity. The best combination (GTC) (gellan gum (0.27%), Cacl2 (1.5%) and Tween 80 (0.01%)) was selected, which exhibited viscosity (11.1 mPas) equivalent to dibutyl phthalate (DBP), which is around 12.0034 mPaS, with an excellent gelling property of the combination. In vitro, analytical characterizations and biological evaluations were carried out for the final formulation. The intermolecular H–bond between gellan gum and Tween 80 was confirmed by FTIR. The amorphous nature of the final composition studied by XRD and DSC analysis reveals its enhanced solubility due to the surface active properties of the optimized composition. The FRAP, ABTS, and DPPH assay proved its dose-dependent antioxidant activity. Moreover, the alternative demonstrated cell viability, enhanced migration, and no apoptosis even at high doses of 2000 µg/ml of GTC tested, representing its safety. In comparison, only 17% of cells were viable at a dose of 1000 µg/ml for DBP, which exhibited cytotoxicity even at low doses in L929 fibroblast cell lines. The alternative’s biodegradation and forced degradation studies proved its positive impact on the environment. Altogether, the developed alternative exhibited similar physicochemical properties as phthalates while having negligible cytotoxicity and potential antioxidant activity, which is necessary for most consumer products, mainly cosmetics. Hence, it can be utilized safely for cosmetic applications. However, further in vivo studies are warranted to identify its systemic effects.

Antimicrobial resistance is a critical global health concern, necessitating innovative therapeutic strategies. Nanosponges, porous and biocompatible nanostructures, are widely used to enhance antimicrobial agent efficacy, yet their direct antimicrobial potential in drug-free formulations remains largely unexplored. This study investigates the antimicrobial and antibiofilm properties of drug-free nanosponges synthesized via emulsion solvent evaporation and solvent methods. Nanosponges were tested against ten clinically relevant pathogens as well as their ability to inhibit biofilm formation and eradicate preformed biofilms in Staphylococcus aureus (MRSA). The drug-free nanosponges exhibited low-to-moderate antimicrobial activity against the common pathogens assessed in this study, while also demonstrating significant antibiofilm efficacy. Despite their negative zeta potential, nanosponges effectively disrupted biofilms, likely through electrostatic interactions and matrix penetration. Nanosponges with higher ethyl cellulose content and optimized β-cyclodextrin-to-diphenyl carbonate (β-CD:DPC) ratios exhibited enhanced biofilm inhibition. This study is the first to evaluate the antimicrobial efficacy of drug-free nanosponges synthesized via these methods, highlighting their potential as standalone antimicrobial agents. By reducing reliance on conventional antibiotics, drug-free nanosponges offer a promising approach for infection control and biofilm-related infections. These findings provide new insights into nanosponge-based antimicrobial strategies beyond drug delivery.

Graphical Abstract

Graphene has been widely studied due to its unique structure and exceptional performance. Various methods are available for preparing graphene, and the electrochemical exfoliation method is chosen for its environmentally friendly, ease of operation, and strong controllability. However, the process of electrochemical exfoliation preparation is influenced by various factors, which still shows challenges of slow exfoliation speed and low yield. In this study, high-purity flexible graphite paper and a saturated calomel electrode (SCE) were used as a three-electrode system, using yield, interlayer spacing, and defect degree as evaluation criteria to explore the influence of electrolytic voltage and electrolyte concentration on graphite electrochemical exfoliation. Using dispersion state, settling time, and defect degree as evaluation criteria to examined the impact of dispersant type on the quality of graphene. The research demonstrated that electrochemical exfoliating at 10 V cell voltage with a bipolar distance of 2 cm in a 0.20 M Na₂SO₄ solution at pH 7 and room temperature, followed by a 10 min ultrasound dispersion in a C₂H₅OH medium at a liquid–solid ratio of 1444:1. The efficiency of graphene production is 59.8%, with low defect levels (I_D/I_G = 0.355), large interlayer spacing (d = 0.350 nm), and a few layers (approximately 4 layers). In addition, the graphene dispersed in a N,N-Dimethylformamide (DMF) medium with a liquid–solid ratio of 1512:1 exhibits the highest level of stability.

Carbon fiber exhibits weak interfacial adhesion with the matrix due to its nonpolar nature, which subsequently limits the mechanical strength of the resulting composites. This research examines the chemical surface modification via oxidation, reduction, and silane functionalization to enhance the fiber-matrix adhesion in carbon fiber-reinforced polymer composites. Carbon fiber was treated using HNO₃ and H₂SO₄:HNO₃ mixture, followed by reduction and silane functionalization with tetraethyl orthosilicate (TEOS). The presence of hydroxyl (–OH) and silanol (–SiOH) groups on TEOS-grafted fiber was confirmed by Fourier transform infrared spectroscopy. This modified fiber, along with epoxy matrix, was used to fabricate the composite using hand lay-up along with compression molding. The resultant composite was investigated for tensile strength, Young’s modulus, and impact strength. The CFRC-4 composite (sample modified with HNO₃ and TEOS) showed highest tensile strength and stiffness, depicting improved interfacial adhesion. Moreover, based on experimental data, the artificial neural network (ANN) model was developed to predict the mechanical performance. At a specific hidden layer size, the optimal performance of stress and strain was precisely predicted by ANN. The experimental validation along with data-driven modeling was combined in this hybrid methodology, providing deeper knowledge of the relation between surface chemistry and composite performance. This approach enables the faster prediction of material characteristics for cutting-edge engineering applications and future research work.

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In the present work, the inhibition performance of sulfaguanidine (SG) as a corrosion inhibitor of iron was investigated mathematically via regression and statistical analysis and theoretically via quantum chemical calculations. Four models were proposed, including a linear model (LM), a linear model with interaction (LIM), a quadratic model with interaction (QIM), and a kinetics model (KM). Among the mathematical models, the QIM was the most accurate one, with a 0.9943 correlation coefficient. The kinetics model demonstrated a correlation coefficient of 0.9954. These models showed that the effect of temperature on the corrosion was more significant than the effect of inhibitor concentration. On the other hand, quantum chemical calculations indicate that the difference between HOMO–LUMO (ΔE) was 0.199 eV, which indicates a high reactivity of SG. The strong adsorption is due to a donor–acceptor bonding connection between the Fe surface and the SG molecules, which has been studied in more detail.