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In recent years, there has been significant interest in photocatalytic technologies utilizing semiconductors and photosensitizers responsive to solar light, owing to their potential for energy and environmental applications. Current efforts are focused on enhancing existing photocatalysts and developing new ones tailored for environmental uses. Anthraquinones (AQs) serve as redox-active electron transfer mediators and photochemically active organic photosensitizers, effectively addressing common issues such as low light utilization and carrier separation efficiency found in conventional semiconductors. AQs offer advantages such as abundant raw materials, controlled preparation, excellent electron transfer capabilities, and photosensitivity, with applications spanning the energy, medical, and environmental sectors. Despite their utility, comprehensive reviews on AQs-based photocatalytic systems in environmental contexts are lacking. In this review, we thoroughly describe the photochemical properties of AQs and their potential applications in photocatalysis, particularly in addressing key environmental challenges like clean energy production, antibacterial action, and pollutant degradation. However, AQs face limitations in practical photocatalytic applications due to their low electrical conductivity and solubility-related secondary contamination. To mitigate these issues, the design and synthesis of graphene-immobilized AQs are highlighted as a solution to enhance practical photocatalytic applications. Additionally, future research directions are proposed to deepen the understanding of AQs' theoretical mechanisms and to provide practical applications for wastewater treatment. This review aims to facilitate mechanistic studies and practical applications of AQs-based photocatalytic technologies and to improve understanding of these technologies.
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The biodegradation of polypropylene (PP), a highly persistent nonhydrolyzable polymer, by Tenebrio molitor has been confirmed using commercial PP microplastics (MPs) (Mn 26.59 and Mw 187.12 kDa). This confirmation was based on the reduction of the PP mass, change in molecular weight (MW), and a positive Δδ13C in the residual PP. A MW-dependent biodegradation mechanism was investigated using five high-purity PP MPs, classified into low (0.83 and 6.20 kDa), medium (50.40 and 108.0 kDa), and high (575.0 kDa) MW categories to access the impact of MW on the depolymerization pattern and associated gene expression of gut bacteria and the larval host. The larvae can depolymerize/biodegrade PP polymers with high MW although the consumption rate and weight losses increased, and survival rates declined with increasing PP MW. This pattern is similar to observations with polystyrene (PS) and polyethylene (PE), i.e., both Mn and Mw decreased after being fed low MW PP, while Mn and/or Mw increased after high MW PP was fed. The gut microbiota exhibited specific bacteria associations, such as Kluyvera sp. and Pediococcus sp. for high MW PP degradation, Acinetobacter sp. for medium MW PP, and Bacillus sp. alongside three other bacteria for low MW PP metabolism. In the host transcriptome, digestive enzymes and plastic degradation-related bacterial enzymes were up-regulated after feeding on PP depending on different MWs. The T. molitor host exhibited both defensive function and degradation capability during the biodegradation of plastics, with high MW PP showing a relatively negative impact on the larvae.
Assuntos
Microbiota , Tenebrio , Animais , Tenebrio/metabolismo , Tenebrio/microbiologia , Plásticos , Polipropilenos/metabolismo , Microplásticos , Peso Molecular , Poliestirenos , Larva/metabolismo , Bactérias/metabolismo , Biodegradação AmbientalRESUMO
Chlorination has been intensively investigated for use in water disinfection and pollutant elimination due to its efficacy and convenience; however, the generation and transportation of chlorine and hypochlorite are energy-consuming and complicated. In this study, a novel binary photosensitizer consisting of anthraquinone-2-sulfonate (AQ2S) and graphene was synthesized via a π-π stack adsorption method; this compound could allow for the chlorination of organic pollutants using on-site chlorine generation. In this photosensitive degradation process, sulfapyridine (SPY) was selected as a model pollutant and was decomposed by the reactive species (Cl2 â¢-, Cl⢠and O2 â¢-) generated during the photosensitive oxidation of chloride. The synthesized AQ2S/graphene exhibited superior activity, and the degradation rate of SPY was over 90 % after 12 h of visible light irradiation with a kinetic constant of 0.2034h-1. Results show that 20 mg AQ2S/GR at a 21 % weight percentage of AQ2S in a pH 7 SPY solution with 1 mol/L Cl- achieved the highest kinetics rate at 0.353 h-1. Free radical trapping experiments demonstrated that Cl2 â¢- and O2 â¢- were the dominant species involved in SPY decomposition under solar light. The reusability and stability of this composite were verified by conducting a cycle experiment over five successive runs. The capacity of photodegradation still remained over 90 % after these 5 runs. The current study provides an energy-efficient and simple-operational approach for water phase SPY control.
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A ternary biochar/vanadium pentoxide/graphite like carbon nitride (BC/V2O5/g-C3N4 denoted BC/VO/CN) composite was prepared by a simple hydrothermal method and its photocatalytic performance was investigated under simulated solar irradiation. The BC/VO/CN was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy, and photoluminescence spectroscopy. Within the BC/VO/CN composites VO nanoparticles were highly crystalline and intertwined with the lamellas of CN, resulting in the formation of well-defined Z-type heterostructures. The photocatalytic activity was evaluated using Rhodamine B as a model pollutant. Under simulated solar (230-780 nm) irradiation the as-prepared BC/VO/CN hybrid materials demonstrated highly improved photocatalytic activity compared to CN, VO and VO/CN. The cause of the solar enhancement could be ascribed to the formation of Z-type heterojunctions between VO and CN, which promoted faster electron-hole separation and more efficient charge transfer. BC, as an electron transfer medium, accelerated the transfer of photogenerated charge carriers and inhibited their recombination.
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In this study, curcumin (Cur) loaded mixed micelles (Cur-PF), composed of Pluronic P123 (P123) and Pluronic F68 (F68), was prepared using the thin-film hydration method and evaluated in vitro. The preparation process was optimized with a central composite design (CCD). The average size of the mixed micelles was 68.2 nm, and the encapsulating efficiency for Cur was 86.93%, and 6.996% for drug-loading. Compared with the Cur propylene glycol solution, the in vitro release of Cur from Cur-PF presented the sustained-release property. The in vitro cytotoxicity assay showed that the IC(50) values on MCF-7 cells for Cur-PF and free Cur in DMSO solution were 5.04 µg/mL and 8.35 µg/mL, while 2.52 µg/mL and 8.27 µg/mL on MCF-7/ADR cells. It could be concluded from the results that P123/F68 mixed micelles might serve as a potential nanocarrier to improve the solubility and biological activity of Cur.