Levofloxacin (LVX) is difficult to be naturally degraded by microorganisms in water, and its residues in water will pose significant risks to human health and ecological environment. In this study, Bi12O17Cl2 was used as the main body, Bi12O17Cl2/GO/Co3O4 composite photocatalyst was prepared by pyrolysis of zeolitic imidazolate framework-67 (ZIF-67) combined with in-situ precipitation method and used to degrade LVX. A sequence of characterizations shows that addition of Co3O4 and graphene oxide (GO) increases the visible light response range, improves the separation efficiency of photogenerated electrons and holes (e--h+) of photocatalyst, and thus improves the degradation efficiency of LVX. Under the optimal reaction conditions, the LVX degradation rate of Bi12O17Cl2/1.5GO/7.5Co3O4 can reach 91.2 % at 120 min, and its reaction rate constant is the largest (0.0151 min-1), which is 2.17, 13.14 and 1.53 times that of Bi12O17Cl2, Co3O4 and Bi12O17Cl2/7.5Co3O4, respectively, showing better photocatalytic performance. Simultaneously, the recycling stability of Bi12O17Cl2/1.5GO/7.5Co3O4 was also verified. The capture experiments and electron EPR test results showed that superoxide radicals (•O2-) and photogenerated holes (h+) were the primary active substances in the reaction process. Finally, combined with HPLC-MS results, the photocatalytic degradation pathway of LVX was derived. This work will provide a theoretical basis for the design of Metal Organic Frameworks (MOFs)-derivative modified Bi12O17Cl2-based photocatalysts.

The application of semiconductor photocatalytic technology to degrade antibiotics in water has been proved to be a promising technology CeO2/L-Bi2O2CO3 composite photocatalyst was efficiently prepared by a facile room temperature precipitation technique and employed in the photocatalytic degradation of ciprofloxacin (CIP). When the concentration of ciprofloxacin was 20 mg/L and the dosage of catalyst was 1.0 g/L, the degradation rate of CIP was 89.96 % after 120 min reaction with optimal catalyst. The addition of L-cysteine not only changed the crystallinity of Bi2O2CO3, but also broadened its visible light absorption range. Additionally, the combination of CeO2 and L-Bi2O2CO3 creates a heterojunction interface accelerates the electron transfer, thereby improving the photocatalytic activity. The degradation process was confirmed to involve the significant participation of 'O2- and h+ through free radical capture experiments. HPLC-MS analysis detected the intermediates of CIP degradation, leading to the proposition of two potential degradation pathways. Moreover, an electron transfer mechanism was suggested by analyzing the Mott-Schottky (M-S) curve and Taut-plot curves. This work provides new paradigm for the rational design of modified Bi2O2CO3-based photocatalysts and the treatment of contain CIP wastewater. (c) 2024 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

In this study, a novel AgNbO3/Bi2MoO6/PANI double Z-scheme heterojunction photocatalyst was created via a solvothermal method, and the method investigates its photocatalytic degradation performance toward norfloxacin (NOR) and other antibiotics. When the content of AgNbO3 is 5 wt % and the content of PANI is 1 wt %, the rate of degradation of AgNbO3/Bi2MoO6/PANI on NOR under visible light is 95.56%, the rate of removal of total organic carbon is similar to 57.45%, and its pseudo-first-order reaction rate constant is 0.01878 min(-1), which surpasses those of AgNbO3, Bi2MoO6, and AgNbO3/Bi2MoO6 by factors of 14.22, 2.46, and 1.35, respectively. At the same time, the AgNbO3/Bi2MoO6/PANI photocatalyst still showed good stability after three cycles. The results demonstrated that the augmented photocatalytic performance of AgNbO3/Bi2MoO6/PANI can be attributed to the formation of a double Z-scheme heterojunction and the incorporation of PANI with excellent conductivity, resulting in the higher efficiency of migration of charge carriers while retaining strong redox ability. This work affords a high-efficiency and environmentally friendly reference for the development of a Bi2MoO6-based heterojunction photocatalyst and its application in the purification of antibiotics in water.

Herein, a novel Bi2WO6/AgBr/Ag4V2O7 double Z-scheme heterojunction photocatalytic material was synthesized by the ultrasonic-assisted coprecipitation method. When the content of AgBr in Bi2WO6/AgBr/Ag4V2O7 is 30 wt % and the content of Ag4V2O7 is 1 wt%, under the optimized reaction conditions, the degradation rate of Bi2WO6/AgBr/Ag4V2O7 to oxytetracycline (OTC) reached 88.13 % within 60 min, and the photocatalytic activity decreased only slightly after repeated use for three times, other than that, the toxicity of OTC to wheat decreased significantly after degradation. The morphology, composition, crystal structure and visible light absorption capacity of the samples are investigated by a series of characterization techniques. Furthermore, free radical capture experiment, electron paramagnetic resonance (EPR) experiment and liquid chromatography-mass spectrometry (LC-MS) were used to explore the possible photocatalytic mechanism and degradation path of OTC. The results show that the improvement of photocatalytic activity is attributed to the construction of a double Z-scheme heterojunction, which provides a more effective structural space for the separation of photogenerated e--h+ pairs. This study provides a new idea for the separation of photogenerated e--h+ pairs and broadens the response range of visible light, and proposes a new strategy for the environmental treatment of photocatalysts.

A simple hydrothermal synthesis method was employed to fabricate a BiOBr/CuFe2O4 composite photo-Fenton catalyst with visible light response in this study. The effects of the CuFe2O4 dosage, the concentration of polyacrylamide (PAM), the reaction time, the pH of the initial solution and the light source on the reaction results were investigated. Under the visible light, ultraviolet light and sunlight irradiation, the chemical oxygen demand (COD) removal rate of PAM (250 mg/L) reached 62.43%, 69.21%, 65.17%, respectively. Simultaneously, the structure, morphology and optical properties were characterized. The improved activity of BiOBr/CuFe2O4 can be attributed to formation of Z-type heterojunction, synergistic effect of photocatalysis and Fenton catalysis. The free radical capture experiments show that center dot O-2(-), h(+) and center dot OH are all active species of BiOBr/CuFe2O4 for decomposing PAM in photo-Fenton reactions. Finally, a possible electron transfer mechanism was proposed through the fitting of Mott-Schottky curve and Taut-plot curves.

Three-dimensions geometry-like plasmon Ag/AgNbO3/BiVO4 (Ag/ANO/BVO) Z-type heterojunction photo-catalyst was synthesized by electrostatic self-assembly and photo-deposition method. Levofloxacin hydrochloride (LEF) became the target degradation object to evaluate photocatalytic activity. The 3-Ag/ANO/BVO showed the best photocatalytic properties compared with other as-synthesized catalysts. The apparent rate constant of 3-Ag/ ANO/BVO was 0.0235 min-1, which separately was 47.00, 5.22, and 1.85 times higher than that of AgNbO3 (ANO), BiVO4 (BVO), and 40%-AgNbO3/BiVO4 (40-ANO/BVO). Several reaction parameters including catalyst dosage, initial LEF concentration, and reaction pH values were filtrated to investigate optimal photocatalytic reaction conditions of the 3-Ag/ANO/BVO composite. The elevated photocatalytic activity can be attributed to the effective migration and separation of photo-induced carriers on the contact interface due to the formation of Z-type heterojunction and broadened visible light absorption range by localized surface plasmon resonance (LSPR) in 3-Ag/ANO/BVO composite. Furthermore, formed intermediates during the photocatalytic oxidation of LEF molecules were detected via high-performance liquid chromatography-mass spectrometry (HPLC-MS). Ul-timately, a plasmonic Z-type photocatalytic mechanism was verified through a variety of characterization tests and simulations method (finite difference time domain, FDTD).

An all-solid-state Z-scheme Bi4O5I2/GO/Bi2Sn2O7 (BI41/1.5GO/BS41) ternary heterojunction was constructed by hydrothermal-ultrasonic assisted aqueous precipitation-heat treatment method. Taking the degradation effect of tetracycline hydrochloride (TC-HCl) as a reference, the BI41/1.5GO/BS41 composite catalyst exhibits the best photocatalytic performance, and its photocatalytic reaction rate constant is 3.82 that of Bi2Sn2O7. When the dosage of BI41/1.5GO/BS41 was 0.8 g/L, the degradation rate of TC-HCl solution with initial concentration of 15 mg/L was 90.31 % (pH=8) under visible light irradiation for 120 min. Moreover, the BI41/ 1.5GO/BS41 also has excellent salt tolerance, universality and recycling stability. The free radical capture experiments and electron paramagnetic resonance (EPR) tests found that & BULL;O2e and h+ were the main active substances for photocatalytic degradation of TC-HCl. The characterization results show that the improve-ment of photocatalytic performance of BI41/1.5GO/BS41 is due to the successful construction of all -solid-state Z-scheme heterojunction with graphene oxide (GO) as an electron transport medium, which not only reduces the transfer resistance of photogenerated electrons but also improves the separation efficiency of photogenerated carriers. Finally, the TC-HCl solution after visible light degradation was detected by the liquid chromatography mass spectrometry (LC-MS), and the possible intermediate products and degrada-tion pathways were speculated. This work provides a new perspective on the application of all-solid-state Z -scheme heterojunction photocatalysts to environmental remediation.& COPY; 2023 Elsevier B.V. All rights reserved.