This research addresses the scalable and inexpensive synthesis of α-Fe2O3via hydrothermal method without any precipitating agent as well as the enhancement of solar driven photocatalytic and H2 production through doping different chromium proportions. Competency of α-Fe2O3, both pure and doped with chromium, to function as photocatalyst was evaluated by its interaction with multiple dyes, which was real-time monitored utilizing (Internet of Things) IoT technique. By adding chromium, the rate of deterioration increased substantially from 15 to 94% for TB under sunlight in a remarkably brief 20 min by employing a very small amount of Cr0.8Fe1.2O3 (0.3 g/L), as evidenced by high degree of mineralization i.e. 85% and LC-HRMS. Also, the rapid breakdown of Trypan Blue (TB) was indicated by BOD5/COD ratio. Moreover, Cr-doped α-Fe2O3 displays excellent H2 production (~ 132 μmol h-1 g-1) as compared to α-Fe2O3. This work highlights the potential utilization of Cr-doped α-Fe2O3 for the purification of industrial waste water and green energy harvesting.

Bismuth oxyfluoride (BiOF) is an emerging class of material with notable chemical stability, unique layered structure and striking energy band structure. Bi-based semiconductor materials and reduced graphene oxides (rGOs) have attracted considerable attention due to their broad spectrum of potential applications. Herein, we successfully synthesised an efficient photocatalyst comprising BiOF-rGO nanocomposites with embedded Ag nanoparticles using a simple hydrothermal method. The synthesised nanocomposites were characterised through Fourier-transform infrared spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy and ultraviolet (UV)-visible spectroscopy. The XRD results indicated the crystalline structures of the BiOF, Ag-doped BiOF and Ag-doped BiOF-rGO composites. Photocatalytic activity assessments focused on the degradation of methylene blue (MB) and methyl orange (MO) dyes under UV-light and sunlight irradiation. The Ag-doped BiOF-rGO composite exhibited significantly enhanced degradation efficiency, achieving 61.81 % and 74.25 % degradation of MB and MO, respectively, after 300 min under UV-light irradiation. On the contrary, pure BiOF demonstrated only 17.63 % and 48.29 % degradation for MB and MO, respectively, under similar conditions. Furthermore, under sunlight irradiation, the Ag-doped BiOF-rGO composite exhibited an MB removal efficiency of 43.87 % after 300 min, whereas pure BiOF showed only 27.47 % under identical conditions. These results underscore the potential of Ag-doped BiOF-rGO composites as highly efficient and adaptable photocatalysts for the photodegradation of organic dyes in industrial wastewater.

Photodegradation of microplastics (MPs) induced by sunlight plays a crucial role in determining their transport, fate, and impacts in aquatic environments. Dissolved black carbon (DBC), originating from pyrolyzed carbon, can potentially mediate the photodegradation of MPs owing to its potent photosensitization capacity. This study examined the impact of pyrolyzed wood derived DBC (5 mg C/L) on the photodegradation of polystyrene (PS) MPs in aquatic solutions under UV radiation. It revealed that the photodegradation of PS MPs primarily occurred at the benzene ring rather than the aliphatic segments due to the fast attack of hydroxyl radical (•OH) and singlet oxygen (1O2) on the benzene ring. The photosensitivity of DBC accelerated the degradation of PS MPs, primarily attributed to the increased production of •OH, 1O2, and triplet-excited state DBC (3DBC*). Notably, DBC-mediated photodegradation was related to its molecular weight (MW) and chemical properties. Low MW DBC (<3 kDa) containing more carbonyl groups generated more •OH and 1O2, accelerating the photodegradation of MPs. Nevertheless, higher aromatic phenols in high MW DBC (>30 kDa) scavenged •OH and generated more O2•-, inhibiting the photodegradation of MPs. Overall, this study offered valuable insights into UV-induced photodegradation of MPs and highlighted potential impacts of DBC on the transformation of MPs.

In this work, a series of thermosensitive ionic liquid functionalized polymers, PNx(IL)y, with controllable morphology and particle size were prepared by free radical polymerization. Then, using the polymer PN64(IL)8 with uniform morphology as a templating agent, the ZnO composite photocatalytic materials doped with rare earth metal Ce were prepared in combination with a microwave-assisted and templated hydrothermal reaction method. Series different Ce-doping amount photocatalytic materials ZnO-Ce-x‱ were characterized by XRD, SEM, TEM, XPS, and other methods. The results demonstrated that the templated materials PN64(IL)8 can prepare ZnO-Ce-2‱ with uniform petaloid ambulacra shape, good distribution of elements, and excellent photocatalytic performance. Photocatalytic degradation experiments of methyl orange (MO) showed that when the Ce-doping amount is only 2‱, the degradation rate of organic dyes can reach 96.5% by reacting the photocatalytic materials in water for 1 h. In addition, this kind of photocatalyst can be used for the degradation of high-concentration MO, as well as being easily recovered and effectively reused by simple filtration. Therefore, the structure of this kind of photocatalyst is controllable in the preparation process with an extremely low Ce-doping amount compared with current reports, and it has a good application prospect in the field of wastewater treatment technology.

Rhodamine B (RhB) is a harmful dye released by industrial wastewaters, thus necessitating its urgent removal. Advanced oxidation processes constitute promising strategies to purify polluted water. Among others, photocatalysis relies on reactive oxygen species (ROS) produced by photocatalytic particles, typically semiconductors like titania or zinc oxide (ZnO), excited by solar or UV-Vis light. However, their wide band gap limits their catalytic capabilities within the absorption of the UV spectrum and causes fast electron-hole recombination. This study presents novel strategies to overcome these limitations: (i) doping semiconductors to increase photocatalytic efficiency; (ii) sensitization-mediated photocatalysis for visible light activation using chemical moieties to trap dye molecules; (iii) nanosizing the photocatalysts to enhance the surface area. ZnO nanoparticles, doped with iron or gadolinium and capped with oleic acid are here synthesized and tested in RhB dye solutions. Remarkably, the results demonstrate an ultra-fast RhB degradation, driven by oleic acid having crucial role in dye adsorption. The degradation mechanisms, including ROS-induced N-deethylation and xanthene group cleavage, are also unraveled. These findings underscore the efficacy of the proposed semiconductor photocatalyst design, highlighting a significant advancement with extensive potential applications in wastewater remediation. This innovative approach paves the way for more efficient and practical solutions to combat industrial dye pollution.

Water pollution seriously affects the development of society and human life. There are various kinds of pollutants, including soluble pollutants and insoluble floaters on the water surface. Herein, the photocatalyst semiconductor BiOCl and superhydrophobic functional particles Mg(OH)2 were deposited on the surfaces of canvas and polyester felt to construct superhydrophobic canvas and polyester felt. The contact angles of the synthetic superhydrophobic canvas and polyester felt were measured as 152° and 155.3°, respectively. The selective adsorption of hexadecane was achieved using the wetting difference between the surface of water and pollutants floating on the surface. For dissolved pollutants, the surface wettability needed to be changed with the help of ethanol. The degradation efficiencies were all greater than 90%, demonstrating the versatility of the synthetic superhydrophobic canvas and polyester felt.

The photodegradation of macroplastics in the marine environment remains poorly understood. Here, we investigated the weathering of commercially available plastics (tabs 1.3 × 4.4 × 0.16 cm), including high-density polyethylene, low-density polyethylene, polypropylene, polystyrene, and polycarbonate, in seawater under laboratory-simulated ultraviolet A radiation for 3-9 months, equivalent to 25-75 years of natural sunlight exposure without considering other confounding factors. After the exposure, the physical integrity and thermal stability of the tabs remained relatively intact, suggesting that the bulk polymer chains were not severely altered despite strong irradiation, likely due to their low specific surface area. In contrast, the surface layer (∼1 μm) of the tabs was highly oxidized and eroded after 9 months of accelerated weathering. Several antioxidant additives were identified in the plastics through low temperature pyrolysis coupled with gas chromatography/mass spectrometry (Pyr-GC/MS) analysis. The Pyr-GC/MS results also revealed many new oxygen-containing compounds formed during photodegradation, and these compounds indicated the dominance of chain scission reactions during weathering. These findings highlight the strong resistance of industrial macroplastics to weathering, emphasizing the need for a broader range of plastics with varying properties and sizes to accurately estimate plastic degradation in the marine environment.

Dezocine, which is well-known as an analgesic, had about 45% share of the Chinese opioid analgesic market. Since drug products containing impurities could bring serious health consequences, it was important to control the generation of impurities and degradation products in the dezocine product. In this study, two kinds of photodegradation products (i.e., degradation product 1 and degradation product 2) in the dezocine injection were isolated using high-performance liquid chromatography. The possible structures of the photodegradation products were identified using both high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy. In addition, the possible generation mechanism showed that degradation product 1 was the oxidation product of dezocine, and degradation product 2 was the coupled dimer of dezocine. Finally, we found that the degradation rate of dezocine increased with the increase in light intensity. Moreover, the degradation of dezocine easily occurred under ultraviolet light in comparison with visible light. A deeper insight into the generation of the photodegradation products in the dezocine injection would directly contribute to the safety of drug therapy based on the dezocine injection by minimizing the degradant/impurity-related adverse effects of drug preparations.

The development of highly efficient and stable visible-light-driven photocatalysts for the removal of herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) from water is still a challenge. In this work, Bi2MoO6 (BMO) materials with different morphology were successfully prepared via a simple hydrothermal method by altering the solvent. The morphology of the BMO material is mainly influenced by the solvent used in the synthesis (H2O, ethanol, and ethylene glycol or their mixtures) and to a lesser extent by subsequent thermal annealing. BMO with aggregated spheres and nanoplate-like structures hydrothermally synthesized in ethylene glycol (EG) and subsequently calcined at 400 °C (BMO-400 (EG)) showed the highest adsorption capacity and photocatalytic activity compared to other synthesized morphologies. Complete degradation of 2,4-D on BMO upon irradiation with a blue light-emitting diode (LED, λmax = 467 nm) was reached within 150 min, resulting in 2,4-dichlorophenol (2,4-DCP) as the main degradation product. Holes (h+) and superoxide radicals (⋅O2-) are assumed to be the reactive species observed for the rapid conversion of 2,4-D to 2,4-DCP. The addition of H2O2 to the reaction mixture not only accelerates the degradation of 2,4-DCP but also significantly reduces the total organic carbon (TOC) content, indicating that hydroxyl radicals are crucial for the rapid mineralization of 2,4-D. Under optimal conditions, the TOC value was reduced by 84.5% within 180 min using BMO-400 (EG) and H2O2. The improved degradation performance of BMO-400 (EG) can be attributed to its particular morphology leading to lower charge transfer resistance, higher electron-hole separation, and larger specific surface area.

This study successfully synthesized ZnO-CuO nanocomposite using the hydrothermal method with Carica papaya leaf extract. The incorporation of the leaf extract significantly enhanced the nanocomposite properties, a novel approach in scientific research. Characterization techniques, including X-ray diffraction, Fourier Transmission Infrared spectroscopy, and Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis, confirmed a cubic crystal structure with an average size of 22.37 nm. The Fourier Transmission Infrared spectrum revealed distinctive vibrations at 627, 661, and 751 cm-1 corresponding to ZnO-CuO nanocomposite corresponding to stretching and vibration modes. SEM images confirmed a cubic-like and irregular structure. The nanocomposite exhibited outstanding photocatalytic activity, degrading methylene blue dye by 96.73% within 120 min under visible light. Additionally, they showed significant antimicrobial activity, inhibiting Staphylococcus aureus (20 mm) and Klebsiella pneumonia (17 mm). The results highlight the efficiency of Carica papaya leaf-derived ZnO-CuO nanocomposite for environmental and health challenges.