Roles of TaON and Ta(3)N(5) in the visible-Fenton-like degradation of atrazine

Construction of the Photocatalytic Film of the Recyclable TaON/Nickel Foam with Ohmic Junction for Efficient Wastewater Treatment

A recyclable photocatalytic film of TaON/Ni foam with ohmic junction is prepared by the electrophoretic deposition technology. The photocatalytic film of 60 mg TaON/Ni foam demonstrates excellent photocatalytic activity and recycling performance for the degradation of basic fuchsin from water. Around 80% of basic fuchsin (50 mL, 10 mg L−1) is removed over 60 mg TaON/Ni foam under irradiation of 72 W LED white light for 5 h. The photocatalytic activity of the film does not significantly decrease after three rounds of use. The active species for the photocatalytic degradation of basic fuchsin are ·O2−, h+ and ·OH.

Degradation of Residual Herbicide Atrazine in Agri-Food and Washing Water

Atrazine, an herbicide used to control grassy and broadleaf weed, has become an essential part of agricultural crop protection tools. It is widely sprayed on corn, sorghum and sugar cane, with the attendant problems of its residues in agri-food and washing water. If ingested into humans, this residual atrazine can cause reproductive harm, developmental toxicity and carcinogenicity. It is therefore important to find clean and economical degradation processes for atrazine. In recent years, many physical, chemical and biological methods have been proposed to remove atrazine from the aquatic environment. This review introduces the research works of atrazine degradation in aqueous solutions by method classification. These methods are then compared by their advantages, disadvantages, and different degradation pathways of atrazine. Moreover, the existing toxicological experimental data for atrazine and its metabolites are summarized. Finally, the review concludes with directions for future research and major challenges to be addressed.

Tantalum Oxynitride Thin Films: Assessment of the Photocatalytic Efficiency and Antimicrobial Capacity

Tantalum oxynitride thin films have been deposited by reactive magnetron sputtering, using a fixed proportion reactive gas mixture (85% N₂ + 15% O₂). To produce the films, the partial pressure of the mixture in the working atmosphere was varied. The characteristics of the produced films were analyzed from three main perspectives and correspondent correlations: the study of the bonding states in the films, the efficiency of photo-degradation, and the antibacterial/antibiofilm capacity of the coatings against Salmonella. X-ray Photoelectron Spectroscopy results suggest that nitride and oxynitride features agree with a constant behavior relative to the tantalum chemistry. The coatings deposited with a higher reactive gas mixture partial pressure exhibit a significantly better antibiofilm capacity. Favorable antibacterial resistance was correlated with the presence of dominant oxynitride contributions. The photocatalytic ability of the deposited films was assessed by measuring the level of degradation of an aqueous solution containing methyl orange, with or without the addition of H₂O₂, under UV or VIS irradiation. Degradation efficiencies as high as 82% have been obtained, suggesting that tantalum oxynitride films, obtained in certain configurations, are promising materials for the photodegradation of organic pollutants (dyes).

Pilot-scale treatment of atrazine production wastewater by UV/O3/ultrasound: Factor effects and system optimization

This study shed light on removing atrazine from pesticide production wastewater using a pilot-scale UV/O₃/ultrasound flow-through system. A significant quadratic polynomial prediction model with an adjusted R² of 0.90 was obtained from central composite design with response surface methodology. The optimal atrazine removal rate (97.68%) was obtained at the conditions of 75 W UV power, 10.75 g h^-1 O₃ flow rate and 142.5 W ultrasound power. A Monte Carlo simulation aided artificial neural networks model was further developed to quantify the importance of O₃ flow rate (40%), UV power (30%) and ultrasound power (30%). Their individual and interaction effects were also discussed in terms of reaction kinetics. UV and ultrasound could both enhance the decomposition of O₃ and promote hydroxyl radical (OH·) formation. Nonetheless, the dose of O₃ was the dominant factor and must be optimized because excess O₃ can react with OH·, thereby reducing the rate of atrazine degradation. The presence of other organic compounds in the background matrix appreciably inhibited the degradation of atrazine, while the effects of Cl^-, CO₃^2- and HCO₃^- were comparatively negligible. It was concluded that the optimization of system performance using response surface methodology and neural networks would be beneficial for scaling up the treatment by UV/O₃/ultrasound at industrial level.

A Visible-Light-Active Heterojunction with Enhanced Photocatalytic Hydrogen Generation

A visible-light-active carbon nitride (CN)/strontium pyroniobate (SNO) heterojunction photocatalyst was fabricated by deposition of CN over hydrothermally synthesized SNO nanoplates by a simple thermal decomposition process. The microscopic study revealed that nanosheets of CN were anchored to the surface of SNO resulting in an intimate contact between the two semiconductors. Diffuse reflectance UV/Vis spectra show that the resulting CN/SNO heterojunction possesses intense absorption in the visible region. The structural and spectral properties endowed the CN/SNO heterojunction with remarkably enhanced photocatalytic activity. Specifically, the photocatalytic hydrogen evolution rate per mole of CN was found to be 11 times higher for the CN/SNO composite compared to pristine CN. The results clearly show that the composite photocatalyst not only extends the light absorption range of SNO but also restricts photogenerated charge-carrier recombination, resulting in significant enhancement in photocatalytic activity compared to pristine CN. The relative band positions of the composite allow the photogenerated electrons in the conduction band of CN to migrate to that of SNO. This kind of charge migration and separation leads to the reduction in the overall recombination rate of photogenerated charge carriers, which is regarded as one of the key factors for the enhanced activity. A plausible mechanism for the enhanced photocatalytic activity of the heterostructured composite is proposed based on observed activity, photoluminescence, time-resolved fluorescence emission decay, electrochemical impedance spectroscopy, and band position calculations.

Anatase Mg0.05Ta0.95O1.15N0.85: a novel photocatalyst for solar hydrogen production

Anatase Mg_0.05Ta_0.95O_1.15N_0.85, exhibiting a narrow band gap for solar hydrogen, is a promising visible-light-response photocatalyst for photocatalytic or photoelectrochemical water splitting.

Novel MoSe2 hierarchical microspheres for applications in visible-light-driven advanced oxidation processes

Advanced oxidation processes as a green technology have been adopted by combining the semiconductor catalyst MoSe2 with H2O2 under visible radiation. And novel three-dimensional self-assembled molybdenum diselenide (MoSe2) hierarchical microspheres from nanosheets were produced by using organic, selenium cyanoacetic acid sodium (NCSeCH2COONa) as the source of Se. The obtained products possess good crystallinity and present hierarchical structures with the average diameter of 1 μm. The band gap of MoSe2 microspheres is 1.68 eV and they present excellent photocatalytic activity under visible light irradiation in the MoSe2-H2O2 system. This effective photocatalytic mechanism was investigated in this study and can be attributed to visible-light-driven advanced oxidation processes.

Visible-light-responsive t-Se nanorod photocatalysts: synthesis, properties, and mechanism

One-dimensional (1D) single-crystalline trigonal selenium nanorods (t-Se NRs) were prepared through a “solid–solution–solid” method by dispersing the prepared amorphous α-Se spheres in ethanol.

Visible light assisted photocatalytic hydrogen generation by Ta2O5/Bi2O3, TaON/Bi2O3, and Ta3N5/Bi2O3 composites

Bi₂O₃/TaON or Ta₃N₅ heterojunctions show significant enhancement in photocatalytic H₂ production under visible light irradiation compared to individual components.

Synthesis of a visible-light active V2O5–g-C3N4 heterojunction as an efficient photocatalytic and photoelectrochemical material

Synergistic enhancement of the photocatalytic degradation of DR81 using V₂O₅–g-C₃N₄ is due to an increase in visible-light absorption efficiency and rapid photoinduced charge separation.

Synthesis and characterization of a CuS–WO3 composite photocatalyst for enhanced visible light photocatalytic activity

WO₃ nanorods and flower-like CuS were synthesized by a hydrothermal process.

Visible-light-driven Bi2O3/WO3 composites with enhanced photocatalytic activity

The heterojunction formed between Bi₂O₃ and WO₃ shows visible-light driven enhanced photocatalytic performance in degradation of Rhodamine B (RhB) and 4 nitroaniline (4-NA).