New Journal of Chemistry最新文献

Due to the increased demand for food supplies, the agricultural sector has been enormously expanded and food production has been enhanced using various agrochemicals. Agrochemicals are known to have adverse effects on human health. Additionally, their extensive use has led to bioaccumulation affecting water quality and aquatic fauna. Taking the problem of bioaccumulation, the present study reports the use of CdS/MAX-phase for the photo mineralization of chlorpyrifos in an aqueous solution. CdS/MAX-phase nanocomposites with different loadings of CdS have been prepared via a simple one-pot thermal decomposition approach at 180 °C for 1 hour. The synthesized CdS/MAX-phase nanocomposites were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS), Raman spectroscopy, and field emission scanning electron microscopy (FE-SEM) techniques. A maximum of 93% degradation of chlorpyrifos under visible light exposure using the nanocomposites was observed in 90 minutes with 3 major intermediates, chlorpyrifos-oxon, 3,5,6-trichloro 2-pyridinol, and pyridine. Studies on the effect of the parameters suggested that the best photocatalytic performance was achieved at pH 7.8 and a dosage of 1 mg mL⁻¹. A detailed investigation of the degradation pathways, mineralization studies, and a comprehensive mechanism supported by LC–MS and scavenger studies have been reported in the present study.

Viscoelastic surfactants (VESs) are critical components of water-based fracturing fluids. However, the challenges related to the large volumes and complex disposal of flowback fluids from conventional VES fracturing fluids remain unresolved. Accordingly, a multifunctional small molecule surfactant gel was successfully prepared in this study. This system exhibits the capacity of in situ gel-breaking and converting it into an oil displacement agent, thus achieving the goal of no fluid return. The gel was composed of erucic acid amidopropyl betaine (EAPB), oleic acid amidopropyl betaine (OAPB), and a thickening agent, and the system was referred to as EOO. On the basis of this gel system, a series of performance parameters have been evaluated through extensive experiments. The research results demonstrated that this gel exhibits good stability, viscoelasticity, sand-carrying capacity, and remarkable self-repairing ability at high shear rates. Additionally, the gel achieves ultra-low interfacial tension and wetting reversal characteristics, both of which are conducive to enhanced oil recovery. Oil displacement and profile control of the gel were evaluated using single and parallel core flooding experiments. The results indicated that the EOO gel increased injection pressure in high-permeability cores and mobilized residual oil in low-permeability cores, thereby expanding the swept volume and enhancing recovery. The small molecule gel developed in this study which can be converted in situ into an oil displacement agent is a candidate for enhanced oil recovery in low-permeability oil fields.

The electrocatalytic urea oxidation reaction (UOR) can serve as an alternative to the anodic oxygen evolution reaction (OER) in water splitting. Therefore, it is of great significance to develop efficient and cheap electrocatalysts to improve the kinetics of the UOR. In this study, a Ni/NiO/NiB@NC-500 composite was prepared by anchoring Ni/NiO/NiB nanoparticles on a nitrogen-doped carbon substrate through a straightforward hydrothermal-pyrolysis method. The optimal Ni/NiO/NiB@NC-500 composite exhibited remarkable activity and stability for the UOR, that is, the current density (j) of Ni/NiO/NiB@NC-500 for the UOR was 264 mA cm⁻² at a potential of 1.67 V. Furthermore, the j retention rate of Ni/NiO/NiB@NC-500 was 84.6% of the initial value after 12 h of chronoamperometry (CA) test. The remarkable performance of Ni/NiO/NiB@NC-500 was ascribed to the following aspects: its hydrophilicity facilitated the adsorption of reactants and products, its porous spongy structure exposed more active sites for the UOR and promoted charge transfer and electrolyte diffusion, and the nitrogen-containing carbon matrix enhanced its electrical conductivity and stability. In addition, the density functional theory (DFT) calculations indicated that the introduction of B significantly reduced the energy barrier of the rate-determining step (RDS) during the UOR.

A series of heterobimetallic (Au⋯Ag interlocking and Au⋯Cu interlocking) [2]catenanes were studied using DFT and TD-DFT methods to explore the relationship between their structures and properties. In order to fully investigate the influence of metal type in these [2]catenanes and compare the similarities and differences between these heterobimetallic and homometallic catenanes, the results were also compared with our previously studied homometallic Au⋯Au interlocking [2]catenane molecules. The results display that the steric hindrance increases with the increase of the number of monomers, and thus the distances between the center and the edge of the rings become longer, demonstrating a trend of outward expansion. As the size of the ring becomes larger, the total weak interaction increases and shows increasingly dispersed distribution. The value of the dispersion interaction energy increases with the overgrowth of the size of molecular systems and correspondingly the energy level of the frontier orbital decreases and the energy gap becomes bigger when two hexamers interlock. Compared with the Au⋯Ag interlocking [2]catenanes, the Au⋯Cu interlocking [2]catenanes present red-shifted absorption spectra, which is consistent with their smaller energy gap. The hole–electron analysis results indicate that the S₀ → S₁ excitations are almost unidirectional charge transfer excitations due to the significant separation of holes and electrons, while for the high-energy excited states, local excitations occupy a dominant position. Through the study of the specific proportion of charge transfer on each fragment in the main transition process, we found that for heterometallic [2]catenanes, the Cu atom in the Au⋯Cu interlocking [2]catenanes has a greater influence on the electronic structure. As for homometallic [2]catenanes, the effects of Au atoms in the two rings are equivalent on the electronic structure.

The widespread use of antibiotics in water has resulted in significant environmental contamination, posing potential health risks. This necessitates the development of efficient methods for their removal from wastewater. This review explores the potential of UiO (Universitetet i Oslo) metal–organic frameworks (MOFs) for the adsorption of dyes and pharmaceuticals from water. UiO MOFs possess exceptional characteristics, including ultra-high porosity and remarkable stability, making them ideal candidates for pollutant adsorption compared to traditional adsorbents. Studies have demonstrated the exceptional performance of UiO MOFs in removing antibiotics from water at various concentrations. This high adsorption efficiency is attributed to their extensive Brunauer–Emmett–Teller (BET) surface area and pore volume, offering numerous binding sites for pollutants. The adsorption affinity between UiO MOFs and antibiotics is governed by various interactions, such as electrostatic interactions, hydrogen bonding, and π–π stacking. These interactions are influenced by the surface charge of the target pollutant and the zeta potential of the MOF surface. Furthermore, the detection mechanisms for antibiotics including, fluorescence quenching, photocatalytic degradation, adsorption, sensing, and other methods, are discussed in this review. Overall, this review emphasizes the promising potential of UiO MOFs as efficient adsorbents for removing antibiotics from water, offering a viable solution for environmental cleanup.

Black carbon (BC) generated from vehicle engine exhaust is a global environmental concern and a freely available carbon source. Herein, onion-like nanocarbon (ONC) isolated from diesel soot (DS) has been surface-functionalized with a small amine named ethylenediamine (en). The amine-functionalized ONC designated as f-en-ONC shows maximum emission at 430 nm under excitation at 350 nm. The aqueous solution of f-en-ONC emits a blue color on UV-light illumination and displays a quantum yield of ∼18%. Among the different tested biomolecules, f-en-ONC selectively detects glutamic acid (GLA) through fluorescence-based quenching. The limit of detection for GLA was found to be ∼ 17.3 μM. Based on spectral overlap studies, UV-visible spectra, and the Stern–Volmer plot, the dynamic quenching mechanism was suggested for the fluorescence-based sensing of GLA. Further, the water-soluble f-en-ONC was used as a bioimaging probe for cancer cells.

Global CO₂ concentrations were reported to exceed 419.3 ppm in 2023, a 51% increase from pre-industrial levels, and emissions will reach 37.4 billion tons. The concomitant rise in global temperature resulting from the increase in atmospheric CO₂ concentration is precipitating a series of unprecedented challenges to global ecosystems. The development of innovative technologies mitigating the effects of climate change is of paramount importance. The solid oxide electrolytic cell (SOEC) represents a promising avenue for future CO₂ resource utilization within the context of electrocatalytic conversion technology. We have employed the exceptional electronic conductivity and redox stability of the La_0.7Sr_0.3CrO_3−δ substrate to enhance the efficacy of the electrolysis process. A series of La_0.7Sr_0.3CrFe_XO_3−δ (LSCF_X, X = 0, 0.025, 0.05, 0.075, 0.1) were prepared by fine-tuning the iron doping at the B-site via glycine liquid phase combustion. The LSCF_0.075 samples exhibited promising results in CO₂ electrolysis, with a CO yield of 5.25 mL min⁻¹ cm⁻² and a current efficiency of 98.12%. This represents a 4.25-fold improvement over the undoped LSC. It is noteworthy that LSCF_0.075 demonstrated exceptional catalytic stability after 50 hours of continuous operation at a high temperature. The industrialization of high-temperature CO₂ electrolysis technology hinges on the development of efficient and stable electrode materials. This study offers promising insights in this regard.

The rotary kiln-electric furnace process represents one of the most efficient industrial pathways for the extraction of nickel from laterite nickel ores. However, the product of this process, a ferronickel alloy, which contains approximately 55–85% iron and 15–45% nickel, necessitates the selective removal of iron before it can be utilized as a nickel source for power battery production. In this paper, an iodination volatilization roasting method was developed and used to separate iron from the ferronickel alloy, and nickel powder was obtained. Thermodynamic analysis and density functional theory (DFT) calculations were applied to elucidate the underlying mechanism. Our findings indicate that, by controlling the reaction temperature, the iodination volatilization roasting process can efficiently volatilize iron and copper, leaving nickel in its metallic state. Specifically, iron and copper volatilization efficiencies reached 96.5% and 97.1%, respectively, while only 8.4% of the nickel was volatilized after 2 hours of roasting at 1000 °C. This mechanistic insight was further supported by experimental roasting data and subsequent characterization of the roasted slags. Moreover, the potential for iodine regeneration within the process was demonstrated through oxidation roasting experiments of FeI₂, confirming the recyclability of iodine in the system. This process provides a route for the high-efficiency separation of Fe from the ferronickel alloy, and Ni in the alloy is obtained in the form of nickel powder.

In this study, we prepared Co and Fe nanoparticles supported on a layered double hydroxide abbreviated as CoNPs@LDH and FeNPs@LDH. The nanostructured catalysts were characterized using inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, infrared spectroscopy (FTIR), X-ray photoemission spectroscopy (XPS), BET surface area analysis and thermogravimetric analysis (TGA) and tested for the oxidation of cyclohexane to KA oil using tert-butylhydroperoxide (TBHP) under solvent-free conditions. CoNPs@LDH appeared to have higher catalytic efficiency than FeNPs@LDH nanocatalysts. Structural analysis revealed that the transition metal nanoparticles are well anchored on the layered double hydroxide, resulting in a fine dispersion of the Co nanoparticles. The CoNPs@LDH nanocatalyst demonstrated a 45.7% conversion of cyclohexane with 95.8% selectivity of KA oil under optimal reaction conditions. Furthermore, the recycling experiment revealed that CoNPs@LDH was a heterogeneous catalyst that could be recycled at least five times without significant loss of catalytic activity. A possible mechanism following the free radical pathway has been proposed.