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Adsorption and photocatalytic oxidation of ibuprofen using nanocomposites of TiO2 nanofibers combined with BN nanosheets: Degradation products and mechanisms
摘要： This study investigated the adsorption and photocatalytic activity of TiO2-boron nitride (BN) nanocomposites for the removal of contaminants of emerging concern in water using ibuprofen as a model compound. TiO2 nanofibers wrapped by BN nanosheets were synthesized by electrospinning method. Characterization of the nanocomposite photocatalysts indicated the BN nanosheets improved the light absorbance and reduced the recombination of the photoexcited charge carriers (e- and h+). The photocatalytic oxidation products and mechanisms of ibuprofen by the TiO2-BN catalysts were elucidated using a multiple analysis approach by high performance liquid chromatography, ultraviolet absorbance, dissolved organic carbon, fluorescence excitation-emission matrices, and electrospray ionization–liquid chromatography–tandem mass spectrometry. The experimental results revealed that the photocatalytic oxidation by the TiO2-BN nanocomposites is a multi-step process and the interactions between ibuprofen molecules and the TiO2-BN nanocomposites govern the adsorption process. The increasing BN nanosheet content in the TiO2 nanofibers facilitated the breakdown of ibuprofen degradation intermediates (hydroxyibuprofen, carboxyibuprofen, and oxypropyl ibuprofen). Kinetic modeling indicated both adsorption and photocatalytic oxidation of ibuprofen by the TiO2-BN nanocomposites followed the first-order kinetic model. The photocatalytic oxidation rate increased with the increasing BN content in the nanocomposite catalysts, which was attributed to the enhanced light absorption capacity and the separation efficiency of the photoexcited electron (e-)-hole (h+) pairs. Multiple photocatalytic cycles were conducted to investigate the reusability and regeneration of the nanofibers for ibuprofen degradation.
关键词： adsorption,titanium dioxide boron-nitride nanocomposites,photocatalytic degradation mechanisms,degradation intermediates,photocatalytic oxidation
更新于2025-09-23 15:23:52
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Activated carbons with adsorbed cations as photocatalysts for pollutants degradation in aqueous medium
摘要： Oxidized activated carbon (AC) based on commercial coconut-shell carbon Aquacarb 607C has been prepared. This AC has micro-mesoporous structure and contains surface carboxyl and phenol/enol groups. Cu- and Co-containing ACs have been synthesized via ion-exchange in acid medium. According to potentiometric titration and XPS data, cation-exchanged forms of AC contain about 0.5% of metal ions. Such cation-containing ACs possess narrowed band gap compared oxidized AC as it is observed for doped oxides. Oxidized and cation-containing ACs have been tested as catalysts in photodegradation of dyes and phenol under UV- and visible irradiation. Initial oxidized AC is photoactive toward rhodamine B and methyl orange under UV illumination but inactive under visible light. For the first time it is shown that cation-exchanged forms of AC have enhanced activity towards rhodamine B, methyl orange and phenol in both UV and visible region. Therefore, the principal possibility of improving the photocatalytic properties of AC by introducing a minimal amount of copper and cobalt cations is shown.
关键词： Cation-exchanged forms,Decolourisation and mineralization,UV and visible irradiation,Activated carbon,Photocatalytic degradation
更新于2025-09-23 15:23:52
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E‐Waste Based V <sub/>2</sub> O <sub/>5</sub> /RGO/Pt Nanocomposite for Photocatalytic Degradation of Oxytetracycline
摘要： The increasing prevalence of antibiotics in the environment has promoted the development of antibiotic resistant microorganisms, and novel approaches are needed to effectively remove antibiotics from water and mitigate this worldwide problem. A reduced graphene oxide-V2O5 (RGOV) nanocomposite was synthesized and used for photocatalytic degradation of the antibiotic oxytetracycline (OTC) in aqueous solution. The Sol–Gel method was employed for V2O5 synthesis from e-waste-based vanadium nitrate, and a one pot solvothermal method was used to synthesize RGOV. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM) with energy dispersive analysis of X-rays (EDAX) confirmed V-O-C bonds on the surface of the RGOV nanocomposites. A decrease in the band gap of V2O5 from 2.21 to 2.13 eV was supported by diffuse reflectance ultraviolet–visible spectrophotometry. OTC adsorption onto the nanocomposite increased with an increase in RGO concentration and saturated at 17% for RGOV with 30% graphene oxide. The composite degraded 90% of the OTC present in aqueous solution (50 mg/L). Platinum (1%) doping further increased OTC degradation by the nanocomposite to 98.7%. Optimum conditions for maximum OTC degradation are (1) an initial OTC concentration of 50 mg/L, (2) a RGOV nanocomposite dose of 0.5 g/L, and (3) a 40 min incubation time. Our results support the potential use of RGOV nanocomposite for OTC photodegradation.
关键词： vanadium pentoxide,photocatalytic degradation,nanocomposite,E-waste,RGO,oxytetracycline
更新于2025-09-23 15:23:52
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Graphitic Carbon Nitride with Carbon Vacancies for Photocatalytic Degradation of Bisphenol A
摘要： Photocatalysis is intensely employed to remove refractory organic pollutants in water, but suffers from low efficiency due to rapid recombination of photogenerated electrons and holes. Here, carbon vacancies modified g-C3N4 (VC-C3N4) is prepared via a handy two-step calcination method and firstly applied in the photocatalytic removal of bisphenol A (BPA). Compared to pristine g-C3N4, the photocatalytic degradation activity of VC-C3N4 for BPA is largely enhanced, whose kinetic constant (k) of BPA degradation is 1.65 times as that of pristine g-C3N4. The enhanced photocatalytic performance of VC-C3N4 is ascribed to critical role of carbon vacancies: On the one hand, carbon vacancies serve as the reservoir of photogenerated electrons to inhibit the recombination of photogenerated holes and electrons. On the other hand, carbon vacancies as conversion centers transfer trapped photogenerated electrons to absorbed O2 for generation of abundant superoxide radical (?O2-), which takes a dominant effect in the photocatalytic degradation process.
关键词： ?O2- species,bisphenol A,carbon vacancies,g-C3N4,photocatalytic degradation
更新于2025-09-23 15:23:52
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Photocatalytic degradation of Microcystin-LR by visible light active and magnetic, ZnFe2O4-Ag/rGO nanocomposite and toxicity assessment of the intermediates
摘要： In this work, we aimed to study photocatalytic degradation of Microcystin-LR (MC-LR), a cyanotoxin known to cause acute as well as chronic toxicity and even mortality. The nanocomposite (NC) based on zinc ferrite (ZnFe2O4) was modified with graphene oxide (GO) and Ag nanoparticles (NPs) to enhance its photocatalytic properties under visible light. The so-formed ZnFe2O4-Ag/rGO NC exhibited superior performance in visible light allowing complete degradation of MC-LR within 120 mins of treatment with pseudo rate constant, k = 0.0515 min-1, several times greater than other photocatalysts, TiO2 (k = 0.0009 min-1), ZnFe2O4 (k = 0.0021 min-1), ZnFe2O4-Ag (k = 0.0046 min-1) and ZnFe2O4/rGO (k = 0.007 min-1) respectively. The total organic carbon analysis revealed that only 22% of MC-LR was mineralized on 120 mins of treatment time indicating presence of different intermediate by-products. The intermediates formed during photocatalytic treatment were identified using liquid chromatography–mass spectrometry (LCMS) based on which probable degradation pathways were proposed. The attack from ?OH radicals formed during the photocatalytic process resulted to hydroxylation and subsequent cleavage of diene bond. The toxicity assessment with Daphnia magna revealed that the degradation process has alleviated toxicity of the MC-LR and no toxic intermediates were formed during the treatment which is very important from eco-toxicological view point. Therefore, ZnFe2O4-Ag/rGO has a good potential in the field of environmental applications as visible light active and magnetic photocatalyst with enhanced performance.
关键词： Photocatalytic degradation,Toxicity,Daphnia magna,Microcystin,Intermediates
更新于2025-09-23 15:23:52
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Atomic layer deposition of hybrid metal oxides on carbon nanotube membranes for photodegradation of dyes
摘要： Synthetic dye pollution is a worldwide problem and quick remedies are urgently needed. Photocatalysis is a promising method to solve this problem and carbon nanotubes (CNTs) are promising components in producing high-performance composite photocatalysts. Nevertheless, the strong hydrophobicity dramatically impedes its application in aqueous environments. In this study, hydrophilic CNT-hybrid metal oxides (ZnO and TiO2) membranes were prepared by atomic layer deposition (ALD). We demonstrate that ALD is an efficient and flexible method to enhance the photocatalytic activity of CNT-based membranes, especially the membranes used in wastewater treatments. The hybrid hexagonal wurtzite ZnO and anatase TiO2 on CNTs after calcination could effectively enhance electron transfer and reduce photo-generated electron-holes recombination. The membranes exhibit preferable photocatalytic activity and stable reusability in dye degradation. This strategy of "ALD on CNTs" is expected to create other CNT-based membranes with additional functionalities and has bright prospect for wastewater treatments.
关键词： Carbon nanotubes,Photocatalytic degradation,Hybrid metal oxides,Atomic layer deposition
更新于2025-09-23 15:23:52
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Constructing a novel Zn2SnO4/C/AgBr nanocomposite with extended spectral response and improved photocatalytic performance
摘要： High-ef?cient photocatalyst based on Zn2SnO4/C/AgBr multi-component heterostructure was prepared via a two-step hydrothermal synthesis method followed by chemical deposition process. Morphological studies showed that ultra-?ne AgBr nanoparticles with the size of 3e5 nm were in situ grown on the surface of the carbon layers attached to Zn2SnO4 nanocrystals. UVevis characterization demonstrated that the co-modi?cation of carbon and AgBr contributed to the dramatically improved light absorption ability of Zn2SnO4/C/AgBr nanocomposites. In the multi-component heterostructured photocatalyst, carbon functioning as a charge mediator plays a pivotal role in separating photogenerated electron-hole pairs ef?ciently. Zn2SnO4/C/AgBr photocatalysts exhibited a signi?cant enhancement of visible-light photocatalytic performance toward the photodegradation of rhodamine B (RhB), resulting from the synergistic effect of the intensi?ed visible-light absorption capacity and ef?cient photogenerated electron-hole pairs transfer. In addition, a proposed schematic mechanism for the signi?cant enhancement of photocatalytic performance is as well put forward on the basis of the experimental results.
关键词： Photocatalytic degradation,Visible-light,Heterostructure,Zn2SnO4/C/AgBr
更新于2025-09-23 15:23:52
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A triple alkoxo bridged dinuclear cobalt(III) complex mimicking phosphatase and showing ability to degrade organic dye contaminants by photocatalysis
摘要： A dinuclear cobalt(III) complex, [(N3)L1CoIIIL2CoIIIL1] (1), has been synthesized and characterized {H2L1 = 2-((1-hydroxybutan-2-ylimino)methyl)-4-bromophenol and HL2 = 2-amino-1-butanol}. Single crystal X-ray diffraction analysis confirmed its structure. Extended supra-molecular architectures were generated in the complex through weak noncovalent interactions. The energetic features of significant supramolecular interactions have been investigated using DFT calculation and further corroborated with NCI plot index computational tool. The complex has been found to mimic the role of phosphatase enzyme efficiently by transforming 4-nitrophenylphosphate to 4-nitrophenolate at room temperature. The reaction follows Michaelis–Menten enzymatic reaction kinetics with turnover numbers of ~1.4 s-1 in aqueous DMF (98% DMF, v/v) medium. The complex also acts as an efficient photocatalyst for degradation of organic pollutants. Methylene blue (MB), a widely used dye in various industries, was selected as a model pollutant in aqueous media to evaluate the photocatalytic effectiveness of the complex.
关键词： DFT calculation,phosphatase mimicking activity,Photocatalytic degradation of methylene blue (MB),Cobalt(III),Crystal structure
更新于2025-09-23 15:23:52
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Nanocrystal-engineered thin CuO film photocatalyst for visible-light-driven photocatalytic degradation of organic pollutant in aqueous solution
摘要： We design a thin CuO film photocatalyst for visible-light-driven photocatalytic degradation of methylene blue (MB). Nanocrystal engineering of the photocatalyst is performed by sputtering with concurrent in-situ thermal treatment. The impacts of the in-situ thermal treatment temperature and sputtering conditions on the material properties of the thin CuO film photocatalyst are investigated in detail. Systematic characterization using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) indicates that deposition at elevated temperature and higher sputtering power significantly improves the surface structure and crystallinity of thin CuO film, which promotes charge transfer and ultimately results in better performance for MB photocatalytic degradation. The best-performing sample is the one sputtered at an elevated temperature of 300 °C and a sputtering power of 300 W. The photodegradation efficiency and physical durability of the samples were also analyzed after using for 5 cycles. The results indicate that in-situ thermal treatment and nanocrystal engineering of the thin CuO film significantly improve the physical durability.
关键词： Thin CuO film photocatalyst,Visible-light-driven photocatalytic degradation,Nanocrystal engineering
更新于2025-09-23 15:23:52
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Activated carbon/metal-organic framework nanocomposite: Preparation and photocatalytic dye degradation mathematical modeling from wastewater by least squares support vector machine
摘要： Herein, Kiwi peel activated carbon (AC), Materials Institute Lavoisier (MIL-88B (Fe), and AC/MIL-88B (Fe) composite were synthesized and used as catalysts to degrade Reactive Red 198. The material properties were analyzed by the FTIR, BET-BJH, XRD, FESEM, EDX, TGA, and UV–Vis/DRS. The BET surface area of AC, MIL-88B (Fe) and AC/MIL-88B (Fe) was 1113.3, 150.7, and 199.4 m2/g, respectively. The band gap values (Eg) estimated by Tauc plot method, were obtained 5.06, 4.19 and 3.79 eV for AC, MIL-88B (Fe) and AC/MIL-88B (Fe), respectively. The results indicated that the AC/MIL-88B (Fe) composite had higher photocatalytic activity (99%) than that of pure AC (79%) and MIL-88B (Fe) catalysts (87%). The decolorization kinetic was matched well with the second-order model. Moreover, the data were modeled using least squares support vector machine which optimized with Cuckoo optimization algorithm. The optimal parameters were found 0.837 and 3.49e+02 based on σ2 and γ values, respectively. The mean square error (MSE) and correlation coefficient (R2) values were obtained 3.97 and 0.948. Therefore, the attained data, materials characterization and prediction of modeling validate the composite form of MIL-88B(Fe) with new AC, had better photocatalytic activity in comparison with the individual form.
关键词： Metal-organic frameworks (MOFs),Synthesis,AC/MIL-88B (Fe) composite,COA-LSSVM modeling,Photocatalytic degradation
更新于2025-09-23 15:23:52