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Photocatalytic removal of diclofenac by Ti doped BiOI microspheres under visible light irradiation: Kinetics, mechanism, and pathways
摘要： BiOI microspheres doped with different amounts of Ti were fabricated and used to remove diclofenac (DCF) from water under visible light irradiation. The fabricated photocatalysts were well characterized. Ti doped BiOI microspheres were found to exhibit higher photocatalytic activity towards DCF under visible light compared with BiOI. Ti doping broadened the band gap of BiOI, which leads to a more negative conduction band edge and a higher reducing activity of photo-generated electrons, thus facilitates ·O2? production during photocatalysis. Among all the fabricated Ti doped BiOI microspheres, TB450 exhibited the highest DCF photocatalytic removal efficiency. Specifically, 99.2% of DCF (C0 = 10 mg L?1) was removed by TB450 (250 mg L?1) at pH 5 within 90 min under visible light irradiation. Scavenger experiments indicated that active species including h+, ·O2? and H2O2 played important roles in the photocatalytic process. The degradation pathway of DCF was elucidated by theoretical density functional theory (DFT) and by-products identification through liquid chromatograph mass spectrometer (LC-MS) analysis. DCF degradation pathway mainly included hydroxylation and the cleavage of C\N bond. DFT calculation can well interpret the degradation mechanism and the sites of DCF molecule with high radical-attack Fukui index (f0) exhibit high reactivity. Acidic condition was found to facilitate the DCF photocatalytic removal. Due to strong photo-stability, Ti doped BiOI microspheres contained good visible-light-driven (VLD) photocatalytic removal efficiency for DCF in the fourth consecutive reused cycle. Ti doped BiOI microspheres can be employed as a cost-effective and high-efficient material to efficiently degrade emerging contaminants (e.g., pharmaceutical) from wastewaters under visible light conditions.
关键词： Ti doped BiOI microspheres,Photocatalysis,Diclofenac,Reuse,Degradation pathway,DFT calculation
更新于2025-09-23 15:21:21
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New Unsymmetrical Bisacridine Derivatives Noncovalently Attached to Quaternary Quantum Dots Improve Cancer Therapy by Enhancing Cytotoxicity toward Cancer Cells and Protecting Normal Cells
摘要： The use of nanoparticles for the controlled drug delivery to cells has emerged as a good alternative to traditional systemic delivery. Quantum dots (QDs) offer potentially invaluable societal benefits such as drug targeting and in vivo biomedical imaging. In contrast, QDs may also pose risks to human health and the environment under certain conditions. Here, we demonstrated that a unique combination of nanocrystals core components (Ag-In-Zn-S) would eliminate the toxicity problem and increase their biomedical applications. The alloyed quaternary nanocrystals Ag-In-Zn-S (QDgreen, Ag1.0In1.2Zn5.6S9.4; QDred, Ag1.0In1.0Zn1.0S3.5) were used to transport new unsymmetrical bisacridine derivatives (UAs, C-2028 and C-2045) into lung H460 and colon HCT116 cancer cells for improving the cytotoxic and antitumor action of these compounds. UAs were coupled with QD through physical adsorption. The obtained results clearly indicate that the synthesized nanoconjugates exhibited higher cytotoxic activity than unbound compounds, especially toward lung H460 cancer cells. Importantly, unsymmetrical bisacridines noncovalently attached to QD strongly protect normal cells from the drug action. It is worth pointing out that QDgreen or QDred without UAs did not influence the growth of cancer and normal cells, which is consistent with in vivo results. In noncellular systems, at pH 5.5 and 4.0, which relates to the conditions of endosomes and lysosomes, the UAs were released from QD-UAs nanoconjugates. An increase of total lysosomes content was observed in H460 cells treated with QDs-UAs which can affect the release of the UAs from the conjugates. Moreover, confocal laser scanning microscopy analyses revealed that QD-UAs nanoconjugates enter H460 cells more efficiently than to HCT116 and normal cells, which may be the reason for their higher cytotoxicity against lung cancer. Summarizing, the noncovalent attachment of UAs to QDs increases the therapeutic efficiency of UAs by improving cytotoxicity toward lung H460 cancer cells and having protecting effects on normal cells.
关键词： lung and colon cancer cells,unsymmetrical bisacridine derivatives,drug-carrier degradation pathway,pH-dependent release,cellular uptake,in vivo antitumor efficacy,Ag-In-Zn-S nanocrystals,cytotoxic activity
更新于2025-09-23 15:21:01
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Visible light photocatalytic degradation of tetracycline with porous Ag/graphite carbon nitride plasmonic composite: Degradation pathways and mechanism
摘要： Ag/g-C3N4 plasmonic photocatalysts with porous structure ( Ag/PCN ) were successfully synthesized via a thermal exfoliation strategy and photo-reduction method. Owing to the combined merits of porous structure and surface plasmon resonance effect of silver nanoparticles, the Ag/PCN catalysts exhibited excellent photocatalytic performance for the degradation of antibiotic agents. With the optimal Ag loading, the Ag/PCN-2 catalyst exhibited the optimal catalytic activity for TC degradation under visible light, which shows about 11.8 times enhancement in the photocatalytic removal efficiency as compared to pure g-C3N4, respectively. This phenomenon can be attributed to the increased specific surface area, broadened visible light absorption and improved charge separation. The radical quenching results confirmed that h+ and ·O2- radicals were the major active species during removal of TC. The degradation of TC is increased with the increment of Ag/PCN-2 catalysts, and the optimum catalyst was found to be 1.67 g/L. The hindering effect of selected of anions ( Cl-, CO3-, H2PO4- ) was found to follow the order H2PO4- > CO3- > Cl-. Ag/PCN-2 sample also possessed high stability after six cycles of reuses. Furthermore, the possible degradation pathways of TC and photocatalytic mechanism over Ag/PCN-2 were proposed in detail.
关键词： g-C3N4,Antibiotic,Degradation pathway,Photocatalysis,Porous structure,Ag
更新于2025-09-23 15:21:01
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Enhanced solar- photocatalytic activity for the simultaneous degradation and detoxification of multiple chlorophenols by embedding plasmonic Pt into TiO2/H3PW12O40 nanopore
摘要： A novel Pt-TiO2/H3PW12O40 film was fabricated, which showed a considerable nonselective degradation and detoxification efficiency towards multiple chlorophenols (CPs), owing to the enhanced yield and separation efficiency of photogenerated electrons and holes. Based on the Mott-Schottky analysis, the carrier density of as-prepared Pt-TiO2/H3PW12O40 film reached 9.72 × 1022 cm?1, which was higher than that of Pt-TiO2, TiO2/H3PW12O40, and TiO2. The outstanding properties were attributed to the SPR effect and the formation of electrons traps from Pt0 (which was well protected by the nanopores that were formed by Ti-O-W and Ti-O-P); and H3PW12O40 that can efficiently transport electrons via its self-generated redox cycle. Meanwhile, the Pt-TiO2/H3PW12O40 film considerably lowers ecological risks of multiple CPs because O2?, as the primary radicals, can largely avoid the generation of products with a quinoid structure. The degradation pathways of multiple CPs were similar to those of single CP because the same hydroxyl substitution intermediate products were detected during the degradation, all of which followed the first-order reaction kinetics. Moreover, the excellent recycling performance of the Pt-TiO2/H3PW12O40 film guaranteed the reduction in economic cost and risks of secondary pollution. Therefore, the Pt-TiO2/H3PW12O40 film showed a considerable application potential in the removal of organic contaminants in aqueous environments.
关键词： Acute toxicity,Schottky junction,SPR effect,Multiple CPs,Degradation pathway
更新于2025-09-23 15:19:57
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Degradation of carbamazepine by vacuum-UV oxidation process: Kinetics modeling and energy efficiency
摘要： Vaccum-ultraviolet (VUV) is effective for elimination of organic contaminants in aqueous environment and degradation of carbamazepine (CBZ) by VUV irradiation was systematically investigated in this study. A dynamic kinetic model was developed to simulate the destruction of CBZ that is mainly initiated by hydroxyl radicals (HO?). The second-order rate constant of the reaction between CBZ and HO? was determined to be 1.4×109 M-1 s-1. Effect of initial CBZ concentration, VUV irradiation intensity and natural organic matter (NOM) were further investigated in several batch experiments. The predicted CBZ removal rates increased with the increasing VUV intensity, while decreased with the increasing initial CBZ and NOM concentrations. Based on the electrical energy per order (EE/O) calculation, the optimal VUV intensity was determined to be 7.5×10-8 Einstein s-1. Meanwhile, several intermediates/products were identified and their time-dependent evolution profiles were determined, and finally a plausible degradation pathway of CBZ was proposed. Ecotoxicity assessment indicated that the potential toxicity of CBZ and its oxidation products should be paid more attention in the VUV process.
关键词： Kinetic model,Degradation pathway,Energy efficiency,Hydroxyl radical
更新于2025-09-19 17:15:36
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An ultrasound-assisted photocatalytic treatment to remove an herbicidal pollutant from wastewaters
摘要： Pollutants of emerging concern contaminate surface and ground water. Advanced oxidation processes treat these molecules and degrade them into smaller compounds or mineralization products. However, little information on coupled advanced oxidation techniques and on the degradation pathways of these pollutants is available to identify possible ecotoxic subproducts. In the present work, we investigate the ultrasound assisted photocatalytic degradation pathway of the herbicide Isoproturon. We worked in batch mode in a thermostatic glass reactor. We compared the activity of nanometric TiO2 P25 with that of Kronos 1077, a micrometric TiO2. We discuss the individual, additive and synergistic degradation action of photolysis, sonolysis, sonophotolysis, and sonophotocatalysis by varying catalyst loading and/or ultrasound power for the last three techniques. With 0.1 g L?1 catalyst, photocatalysis and sonophotocatalysis completely degrade Isoproturon within 240 min and 60 min, respectively (> 99 % conversion). Sonophotocatalysis breaks Isoproturon down into smaller molecules than photocatalysis alone.
关键词： degradation pathway,wastewater treatment,Isoproturon,sonophotodegradation,micrometric catalyst
更新于2025-09-19 17:15:36
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Fabrication of vessel–like biochar–based heterojunction photocatalyst Bi2S3/BiOBr/BC for diclofenac removal under visible LED light irradiation: Mechanistic investigation and intermediates analysis
摘要： In this work, a novel, economical and effective vessel–like biochar–based photocatalyst Bi2S3/BiOBr/BC was synthesized by a facile one–pot solvothermal method for the first time. A series of characterization analyses demonstrated the successful preparation of photocatalyst Bi2S3/BiOBr/BC. Furthermore, diclofenac (DCF) as the target contaminant was applied to elucidate the enhanced photocatalytic performance (93.65%, 40 min) under energy–saving visible LED light irradiation. Comparison experiments among different photocatalysts and photoelectrochemical tests results illustrated that excellent photocatalytic performance of Bi2S3/BiOBr/BC 10% might be attributed to the electrons transfer of biochar and higher charge separation efficiency of heterojunction structure. Besides, lower electrical energy per order value indicated photocatalyst/visible LED light system was more energy–saving. Proper photocatalyst dosage (0.6 g/L) and relatively acidic water environment (pH=5.0) would be beneficial to DCF photodegrdation by Bi2S3/BiOBr/BC. Good reusability and stability of Bi2S3/BiOBr/BC were verified via five consecutive recycle experiments. Furthermore, the role of active species was determined through trapping experiments and ·O2– and h+ dominated the photodegradation reaction to mineralize DCF molecules. Eleven main intermediates and four possible photodegradation pathways were proposed by HRMS analysis. Accordingly, photocatalyst Bi2S3/BiOBr/BC would provide potential technical support for emerging pollutant removal in water matrix.
关键词： Diclofenac,Photocatalytic mechanism,Bi2S3/BiOBr/BC,Visible LED light,Degradation pathway
更新于2025-09-19 17:13:59