Enhancing the efficiency of electron transfer and augmenting the utilization rate of peroxymonosulfate (PMS) pose challenges for advanced oxidation processes (AOPs). A high-performance bimetallic-doped catalyst (MnCo/CeO2) with an appropriate concentration of oxygen vacancies (OVs) was successfully designed using a straightforward synthesis strategy. It primarily activates PMS through non-radical pathways. Systemic characterization, experiments, and theoretical calculations have demonstrated that reasonable OVs and the Mn/Co bimetallic doping strategy effectively modulated the surface spatial electron structure and greatly improved interfacial electron transfer processes (ETP). Ultimately, MnCo/CeO2 exhibits a remarkable ciprofloxacin (CIP) removal efficiency of 93.71% (k = 0.03501 min−1) within 50 min (after 5 cycles, 89%), which is 5.03 times faster than that of traditional CeO2 (k = 0.00696 min−1), and the possible degradation pathway as well as toxicity of intermediate products were identified using LC-MS, Fukui function analysis, and toxicity evaluation. This work proposes a feasible strategy for designing bimetallic-doped metallic oxide catalysts, which have great application potential for the degradation of organic contaminants under actual harsh environmental conditions.
Opened multiwalled carbon nanotubes (O-MWCNT) were prepared by unzipping MWCNTs using Hummers' method and decorated with CuO to form a nanohybrid (O-MWCNT/CuO) through a simple co-precipitation technique, aimed at developing a novel electrochemical sensor. The O-MWCNT/CuO composite was used to modify a glassy carbon electrode (GCE) for the sensitive detection of the antipyretic drug acetaminophen (ACT) in various matrices. O-MWCNT/CuO was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible spectroscopy, cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS), which confirmed the successful formation of the nanocomposite as well as its electrical conductivity and catalytic properties. The sensor demonstrates a wide linear detection range (0.005–1450 μM), with a low detection limit (LOD) of 7.2 nM and excellent sensitivity of 0.019 μA cm−2 μM−1. Additionally, the sensor demonstrated good stability (maintaining performance over 65 cycles) and selectivity in various co-interfering compounds. Notably, the electrochemical sensor was applied for the detection of ACT in environmental water samples, pharmaceutical formulations, human biological fluids, and fenugreek plant extracts, achieving good recovery rates (97.37–100.20%) with relative standard deviations (RSD) ranging from 1.0% to 3.3%, using the standard addition method. The novelty of this work lies in the development of a highly sensitive, stable, and selective GCE-modified sensor for ACT detection, with promising applications in real-world sample analysis.
Herein, an ultrasonication approach was used to anchor In2S3 quantum dots (QDs) onto oxygen-doped graphitic carbon nitride (O@g-C3N4), resulting in a novel heterojunction catalyst. Characterization techniques validated the successful incorporation of In2S3 into the O@g-C3N4 matrix, with transmission electron microscopy (TEM) indicating the existence of In2S3 QDs measuring 6.62 nm. The photocatalyst (0.24 g L−1) effectively degraded 15 mg L−1 of metronidazole (MDZ) via persulfate (PS) activation under visible light irradiation, with a degradation efficiency of 98.17 ± 1.53% in 25 min. This improved performance was due to the creation of an n–n heterojunction, in which the Fermi energy levels of O@g-C3N4 and In2S3 reached equilibrium, resulting in an internal electrostatic field at their interface that enabled efficient carrier transfer. Combining trapping tests with a well-established S-scheme charge transfer mechanism indicated an excellent photocatalytic process for the In2S3/O@g-C3N4 heterojunction. Chemical oxygen demand (COD) and total organic carbon (TOC) studies were used to measure the photocatalyst's efficacy in degrading MDZ, while its capacity to degrade other pollutants was also tested. Furthermore, after seven cycles, the catalyst displayed remarkable reusability and maintained efficiency in various water conditions with coexisting species such as cations, anions, and organic compounds. As a result, the discovered In2S3/O@g-C3N4 heterojunction catalyst shows significant promise for the effective and long-term removal of MDZ and other toxic pollutants from water, paving the way for enhanced water treatment technologies.
A reasonable planting density is vital for wheat resource efficiency and yield enhancement. However, systematic research on the impact of spraying TiO2-NPs on wheat growth, metabolism, and stress tolerance cultivated in cadmium (Cd)-contaminated soil is limited, especially in integration with planting density, requiring a deeper understanding. Our study showed that spraying with 3.1 mg per plant TiO2-NPs (in pots) and 21.6 mg m−2 TiO2-NPs combined with high planting densities (in the field) both significantly reduced the Cd content in wheat grains by 27.9 and 35.7%, respectively. Immobilization of subcellular water-soluble Cd and the conversion of Cd into inactive plant components in leaves were the primary reasons for this reduction. Metabolomics further revealed the up-regulation of metabolites related to antioxidant activity, plant stress resistance, growth promotion, and the tricarboxylic acid (TCA) cycle, which promotes plant growth, enhances wheat antioxidant enzyme activity, and alleviates oxidative stress. Transcriptomic analysis validated the association between these responses and improved plant stress resistance, with genes such as MYB, WRKY, P450, and Cd membrane transport-related genes like ABCG2 and ABCC3 contributing to the decrease in Cd levels in wheat. Importantly, the Cd-associated human health risk index was also reduced via foliar TiO2-NPs application. Overall, foliar spraying of TiO2-NPs combined with high plant density was beneficial in alleviating Cd levels in wheat grains, limiting the risk of Cd exposure to human health via the food chain.
Nanotechnology offers a variety of new tools for the design of next-generation personal protective equipment (PPE). One example is the use of two-dimensional materials as coatings that enhance the performance and ergonomics of elastomeric gloves designed to protect users from hazardous chemicals. Desirable features in such coatings may include molecular barrier function, liquid droplet repellency, stretchability for compatibility with the elastomer, breathability, and an ultrathin profile that preserves the user's manual dexterity and tactile sensation. The present work explores the potential of engineered graphene-based films with out-of-plane texturing as a novel platform to meet these multifold requirements. Graphene-based films in different formulations were fabricated from water-borne inks by vacuum filtration and solution casting methods on glove-derived nitrile rubber substrates. The various coatings were then subjected to tests of molecular permeation by model volatile organic compounds, droplet contact angle, breathability, and mechanical stability during stretching and solvent immersion. The films dramatically improve the barrier properties of glove-derived nitrile. The out-of-plane graphene texturing imparts stretchability through microscale folding/unfolding, while also enhancing droplet repellency in some cases through a lotus-like roughening effect. The combined results suggest that engineered textured graphene-based films are a promising platform for creating multifunctional coatings for a next generation of chemically protective gloves and other elastomer-based PPE.
Oil spills frequently cause devastating impacts on coastal ecosystems and communities. Spill response methods for coastal regions, such as spill-treating agents, sorbents, and bioremediation, may face constraints due to environmental concerns, limited absorption capacity, and low effectiveness. Fortunately, the emergence of nanomaterials with unique properties has introduced promising solutions for coastal oil spill remediation. These nanomaterials have shown great potential in oil removal, recovery, and degradation through different mechanisms. Nanoparticles or nanocomposites can interact with spilled oil by breaking it into small droplets and forming stable Pickering emulsions. They can also remove oil from water by absorption, adsorption, or in combination with both due to their large surface area and numerous sorption sites. Furthermore, some nanomaterials possess catalytic activity to speed up the degradation of petroleum hydrocarbons into less harmful compounds. Moreover, the introduction of nanomaterials can be beneficial for bacteria proliferation, nutrient supply, and maintenance of favorable conditions, thereby accelerating the oil biodegradation process by microorganisms. In this perspective, we discussed the interactions between nanomaterials and oil, as well as their applications in various coastal oil spill response methods.
Over the past few years, nanotechnology and nanomaterials have played a crucial role in the agriculture sector. Notably, among different types of nanomaterials, metal–organic frameworks (MOFs) have attracted significant attention owing to their porosity, organic composition, biocompatibility, and tailored structural and compositional properties. In this research work, we have effectively prepared four types of MOFs including ZIF-8, ZIF-67, PFC 6, and PFC-7. Interestingly, among all the prepared MOFs, ZIF-67 exhibited exceptional performance. With the aim to further improve the efficacy of ZIF-67, we decorated it with SnO2. Among the as-prepared samples, the optimal sample 5SnO2/ZIF-67 nanocomposite exhibited exceptional efficiency in terms of its high chemical and thermal stability, large surface area, selective antipathogenic activities, high catalytic activities, and disease resistance properties. Based on our various characterization techniques, such as XRD, DRS, PL, FS, BET, FT-IR, and RAMAN, it has been confirmed that the incorporation of SnO2 into ZIF-67 leads to adjustments in band gaps, enhanced stability, modulated photo-electrons, large surface area, abundant active sites, and upgraded adsorption and selectivity for antipathogenic and pesticide degradation activities. As compared to pure ZIF-67, the most active sample 5SnO2@ZIF-67 showed ∼4.5 and ∼2.6 times significant improvement for glyphosate (GLY) and acephate (ACPH) degradation, respectively. Remarkably, our prepared samples also offered potent performances against various pathogens in Luria–Bertani medium. Based on the scavenger tests, ·OH and O2− are respectively responsible for GLY and ACPH decomposition. Accordingly, the activity improvement mechanism and biochemical pathways are proposed. Finally, our novel research work will provide a gateway for the fabrication of MOF-based green nanomaterials that will unlock a wide range of opportunities and applications in antipathogenic and pesticide degradation activities and tomato plant growth.
Efficient recovery of palladium (Pd) from waste sources is of paramount importance due to its limited natural reserves and potential environmental hazards. Herein, a carbon sorbent, namely sulfur-functionalized porous carbon microspheres (SPCMs), was used to selectively capture Pd(II) from acidic solution. SPCMs exhibited high efficiency for the adsorption separation of Pd(II) from 0.5 M to 6 M HNO3 solution. The adsorption kinetics of Pd(II) matched well with the pseudo-second-order model. The adsorption reached equilibrium after 130 minutes and the adsorption capacity of Pd(II) was 79.3 mg g−1 in 1 M HNO3 solution. The Freundlich isotherm model exhibited a better description of the Pd(II) adsorption, suggesting that the Pd(II) adsorption is a multilayer adsorption process. SPCMs showed a high selectivity for the capture of Pd(II) in simulated acidic wastewater with 26 metal ions, and the selectivity increased with the increase of HNO3 concentration. The adsorption capacity per US dollar of Pd(II) by SPCMs from HNO3 solution is much higher than those of previously reported sorbents, exhibiting a high economic viability of SPCMs for Pd(II) capture from acidic solution. The adsorbed Pd(II) could be desorbed using 1.0 M thiourea and 0.1 M HNO3, and the SPCM sorbent maintained a high adsorption capacity after five adsorption–desorption cycles. Characterization and theoretical calculations revealed that the adsorption of Pd(II) on the SPCM sorbent is dominated by the coordination of [Pd(NO3)2] with O/S containing groups and some of the Pd(II) is reduced to Pd(0). The excellent adsorption performance of SPCMs provides a feasible and low-cost strategy for the selective recovery of Pd(II) from acidic wastewater.
Development of solar energy converters with earth-abundant and environmentally friendly materials is one of the key routes explored towards a sustainable future. In this work, crystalline delafossite-phase CuAlO2 and CuFeO2 thin film solar water splitting photocathodes were fabricated using pulsed laser deposition. It was found that the desired delafossite phase was formed only after high temperature annealing in an oxygen-free atmosphere. The homogeneous delafossite bulk structure of the films was determined by correlating simulation results from first-principles calculations with synchrotron-based X-ray absorption near edge structure (XANES) spectroscopy. Both CuAlO2 and CuFeO2 photocathodes are active for solar water splitting, with the latter more efficient due to its narrower band gap and improved light absorption.
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