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It finds that CQDs synthesized by hydrothermal method possess obvious upconversion properties that could transfer low energy photons to high energy photons, resulting in enhanced ...visible light response and utilization. Herein, carbon quantum dots (CQDs) modified TiO2 photocatylysts were successfully prepared by a facile sol-gel method. Photophysical and surficial properties of the as-prepared composite photocatalyst were investigated in details. Furthermore, photocatalytic performance was tested by degrading methylene blue (MB) under visible light irradiation. The degradation efficiency of methylene blue (MB) is as high as 90% within 120min, which is 3.6 times higher than that of pure TiO2.
Manganese (Mn) is an essential element for plant growth due to its participation in a series of physiological and metabolic processes. Mn is also considered a heavy metal that causes phytotoxicity ...when present in excess, disrupting photosynthesis and enzyme activity in plants. Thus, Mn toxicity is a major constraint limiting plant growth and production, especially in acid soils. To cope with Mn toxicity, plants have evolved a wide range of adaptive strategies to improve their growth under this stress. Mn tolerance mechanisms include activation of the antioxidant system, regulation of Mn uptake and homeostasis, and compartmentalization of Mn into subcellular compartments (e.g., vacuoles, endoplasmic reticulum, Golgi apparatus, and cell walls). In this regard, numerous genes are involved in specific pathways controlling Mn detoxification. Here, we summarize the recent advances in the mechanisms of Mn toxicity tolerance in plants and highlight the roles of genes responsible for Mn uptake, translocation, and distribution, contributing to Mn detoxification. We hope this review will provide a comprehensive understanding of the adaptive strategies of plants to Mn toxicity through gene regulation, which will aid in breeding crop varieties with Mn tolerance via genetic improvement approaches, enhancing the yield and quality of crops.
Spinel ZnFe
2O
4 nanospheres were synthesized in high yield via a general, one-step and template-free solvothermal route. The sphere-like ZnFe
2O
4 showed dramatically enhanced photocatalytic ...degradation of rhodamine B.
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► Sphere-like ZnFe
2O
4 nanostructures are successfully synthesized via a facile method. ► The structural properties for the promoted photocatalytic performance are discussed. ► The sphere-like ZnFe
2O
4 shows enhanced photocatalytic degradation of rhodamine B. ► Hydroxyl radicals play an important role in the photocatalytic degradation of rhodamine B.
Spinel zinc ferrite nanospheres with diameters of about 212
nm were synthesized in high yield via a general, one-step and template-free solvothermal route. The prepared nanospheres had cubic spinel structure and exhibited good size uniformity and regularity. The absorption edge of ZnFe
2O
4 nanospheres shifted to a higher energy in the UV–Vis absorption spectrum compared with that of ZnFe
2O
4 nanoparticles. The ZnFe
2O
4 nanospheres exhibited remarkably high surface photovoltage response in the UV and visible region, suggesting the enhanced separation ability of photogenerated electrons and holes. The dramatically enhanced photocatalytic activity of the ZnFe
2O
4 nanospheres was evaluated in the decomposition of rhodamine B under Xe lamp irradiation. Hydroxyl radicals on the surface of photoilluminated ZnFe
2O
4 nanospheres were detected by the photoluminescence technique, which suggested that hydroxyl radicals played an important role in the photocatalytic reaction. This study provided new insight into the design and preparation of functional nanomaterials with sphere structure in high yield, and the as-grown architectures demonstrated an excellent ability to remove organic pollutants in wastewater.
Carbon Aerogels for Environmental Clean‐Up Gan, Guoqiang; Li, Xinyong; Fan, Shiying ...
European journal of inorganic chemistry,
July 23, 2019, Letnik:
2019, Številka:
27
Journal Article
Recenzirano
Carbon aerogels are a fascinating three‐dimensional (3D) monolithic porous material with remarkable physicochemical properties, including low density, large surface area, abundant pore structure, ...high electrical conductivity, chemical stability, environmental compatibility, adjustable surface chemistry, as well as controllable structural features. These properties endow carbon aerogels with excellent adsorption and catalytic performance. Therefore, they are widely applied in environmental chemistry for removing pollutants like oils, toxic organic solvents, dyes, heavy metal ions in aquatic environments, and volatile organic compounds (VOCs), carbon oxides (CO2, CO), nitrogen oxide (NOx), and hydrogen sulfide (H2S) in the atmosphere. In this paper, the preparation processes of carbon aerogels are fully reviewed, and their applications for environmental clean‐up based on adsorption and catalytic action are thoroughly addressed. In each section, the most recent representative studies will be highlighted. Finally, the challenges, outlooks, and prospects in this emerging and promising research field will be briefly discussed.
Carbon aerogels have excellent properties including low apparent density, large specific surface area, abundant pore structure, high electrical conductivity, good chemical stability, environmental compatibility, as well as modifiable surface chemistry and controllable texture and structural features. Their applications as adsorbents and catalysts for environmental clean‐up have been reviewed.
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MnOx-Fe3O4 nanomaterials were fabricated by using the innovative scheme of pyrolyzing manganese-doped iron-based metal organic framework in inert atmosphere and exhibited ...extraordinary performance of NO reduction by CO (CO-SCR). Multi-technology characterizations were conducted to ascertain the properties of fabricated materials (e.g., TGA, XRD, SEM, FT-IR, XPS, BET, H2-TPR and O2-TPD). Moreover, the interaction between reactants and catalysts was ascertained by in situ FT-IR. Experimental results demonstrated that Mn was an ideal promoter for iron oxides, resulting in decrease of crystallite size, improve reducibility property, enhance the mobility and the amount of lattice O2− species, as well as strength the adsorption ability of active NO and CO to form multiple species (e.g., nitrate and carbonate). The unprecedented enhancement of CO-SCR activity over Mn-Fe nanomaterials follows the Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) reaction pathway.
A ternary Ag/AgBr/TiO2 nanotube array electrode with enhanced visible-light activity was synthesized by a two-step approach including electrochemical process of anodization and an in situ ...photoassisted deposition strategy. The dramatically enhanced photoelectrocatalytic activity of the composite electrode was evaluated via the inactivation of Escherichia coli under visible light irradiation (λ>420 nm), whose performance of complete sterilization was much superior to other reference photocatalysts. PL, ESR, and radicals trapping studies revealed hydroxyl radicals were involved as the main active oxygen species in the photoelectrocatalytic reaction. The process of the damage of the cell wall and the cell membrane was directly observed by ESEM, TEM, and FTIR, as well as further confirmed by determination of potassium ion leakage from the killed bacteria. The present results pointed to oxidative attack from the exterior to the interior of the Escherichia coli by OH•, O2 •–, holes and Br0, causing the cell to die as the primary mechanism of photoelectrocatalytic inactivation.
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▶ ZnAl2O4 nanoparticles could be synthesized by a facile solvothermal method. ▶ ZnAl2O4 nanoparticles show high efficiency (90.25%) in photocatalytic degradation of toluene. ▶ The ...toluene could be finally mineralized into carbon dioxide and water.
The development of a “green” treatment process for typical indoor pollutants such as toluene is greatly desirable. In this study, ZnAl2O4 nanoparticles were prepared via three different routes, i.e., solvothermal, citrate precursor and hydrothermal methods. Their structural properties were systematically investigated by X-ray powder diffraction (XRD), scanning electronic microscopy (SEM), energy-dispersive X-ray spectra (EDX), Brunauer–Emmett–Teller (BET), UV–vis diffuse reflectance spectroscopy (DRS), and Fourier transform infrared spectroscopy (FT-IR) techniques. The photo-induced charge separation in the samples was demonstrated by surface photovoltage (SPV) measurement. The photocatalytic performances of the ZnAl2O4 samples and nanostructured TiO2 samples were comparatively studied by the degradation of gaseous toluene under UV lamp irradiation in in situ FTIR reactor. The results indicated that the sample synthesized by facile solvothermal method exhibited about 90% photocatalytic efficiency of toluene. The toluene was mineralized into carbon dioxide and water as the major species. The photocatalytic oxidation of gaseous pollutant over UV-illuminated ZnAl2O4 is a promising technique for air purification.
A bio-electrochemical strategy was developed for constructing a simple and sensitive levofloxacin (LEV) sensor based on a single chamber microbial fuel cell (SC-MFC) using FePO4 nanoparticles (NPs) ...as the cathode catalyst instead of traditional Pt/C. In this assembled sensor device, FePO4 NPs dramatically promoted the electrooxidation of oxygen on the cathode, which helps to accelerate the voltage output from SC-MFC and can provide a powerful guarantee for LEV detection. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to fully characterize the FePO4 NPs. Under the optimized COD condition (3mM), the LEV with a concentration range of 0.1–1000µg/L could be detected successfully, and exhibited the excellent linear interval in the concentration range of 0.1–100µg/L. During this range of concentrations of LEV, a temporary effect on the anode of exoelectrogenic bacterial in less than 10min could occur, and then came back to the normal. It exhibited a long-term stability, maintaining the stable electricity production for 14 months of continuous running. Besides, the detection mechanism was investigated by quantum chemical calculation using density functional theory (DFT).
•FePO4 based single chamber air cathode MFC was constructed.•The SC-MFC exhibited high sensitivity and lasting stability for LEV online detection.•The whole detection for different concentrations of LEV can be finished in 5min.•The excellent degradation range of LEV in this biosensor was also proposed.
Differently sized Cu2O nanoparticles have been assembled photocatalytically on the surface of self-organized highly oriented TiO2 nanotubes obtained by anodization of a Ti sheet in ...fluoride-containing electrolytes. X-ray diffraction analysis identifies an anatase structure and fine preferential orientation of ⟨101⟩ planes. The UV−vis absorption edge of the TiO2 nanotube arrays shift to lower energy after Cu2O loading. The composite array electrode exhibits a higher photovoltage response than the TiO2 powders directly deposited on a Ti sheet. The highest photoconversion efficiencies observed for the Cu2O-loaded electrode are 17.2% and 0.82% under UV light and visible light irradiation, respectively. Especially, the composite array electrode shows a higher efficiency than the nonloaded one for the photoelectrocatalytic decomposition of 4-chlorophenol. The improved photoeletrocatalytic activity of the TiO2/Cu2O composite array electrode is attributed to the synergistic effect of Cu2O nanoparticles and TiO2 nanotube arrays. The Cu2O nanoparticles could enhance the efficiency of photon harvesting and reduce the chances of electron−hole recombination by sending the electrons to the conduction band of TiO2 nanotubes. The accumulated electrons in the conduction band of TiO2 nanotubes would reduce oxygen to form peroxides for enhanced advanced oxidation. The byproducts were identified by high-performance liquid chromatography.
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