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Ivan R, Popescu C, Antohe VA, Antohe S, Negrila C, Logofatu C, del Pino AP, György E. Iron oxide/hydroxide-nitrogen doped graphene-like visible-light active photocatalytic layers for antibiotics removal from wastewater. Sci Rep 2023; 13:2740. [PMID: 36792714 PMCID: PMC9932170 DOI: 10.1038/s41598-023-29927-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 02/13/2023] [Indexed: 02/17/2023] Open
Abstract
Hybrid layers consisting of Fe oxide, Fe hydroxide, and nitrogen doped graphene-like platelets have been synthesized by an eco-friendly laser-based method for photocatalytic applications. The complex composite layers show high photodecomposition efficiency towards degradation of antibiotic molecules under visible light irradiation. The photodecomposition efficiency was investigated as a function of relative concentrations of base materials, Fe oxide nanoparticles and graphene oxide platelets used for the preparation of target dispersions submitted to laser irradiation. Although reference pure Fe oxide/Fe hydroxide layers have high absorption in the visible spectral region, their photodecomposition efficiency is negligible under the same irradiation conditions. The high photocatalytic decomposition efficiency of the nanohybrid layer, up to 80% of the initial antibiotic molecules was assigned to synergistic effects between the constituent materials, efficient separation of the electron-hole pairs generated by visible light irradiation on the surface of Fe oxide and Fe hydroxide nanoparticles, in the presence of conducting graphene-like platelets. Nitrogen doped graphene-like platelets contribute also to the generation of electron-hole pairs under visible light irradiation, as demonstrated by the photocatalytic activity of pure, reference nitrogen doped graphene-like layers. The results also showed that adsorption processes do not contribute significantly to the removal of antibiotic molecules from the test solutions. The decrease of the antibiotic concentration under visible light irradiation was assigned primarily to photocatalytic decomposition mechanisms.
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Affiliation(s)
- R. Ivan
- grid.435167.20000 0004 0475 5806National Institute for Lasers, Plasma and Radiation Physics, PO Box MG 36, 077125 Măgurele, Ilfov Romania ,grid.5100.40000 0001 2322 497XFaculty of Physics, University of Bucharest, Atomiștilor 405, 077125 Măgurele, Ilfov Romania
| | - C. Popescu
- grid.435167.20000 0004 0475 5806National Institute for Lasers, Plasma and Radiation Physics, PO Box MG 36, 077125 Măgurele, Ilfov Romania
| | - V. A. Antohe
- grid.5100.40000 0001 2322 497XFaculty of Physics, University of Bucharest, Atomiștilor 405, 077125 Măgurele, Ilfov Romania ,grid.7942.80000 0001 2294 713XInstitute of Condensed Matter and Nanosciences (IMCN), Université Catholique de Louvain (UCLouvain), Place Croix du Sud 1, 1348 Louvain-La-Neuve, Belgium
| | - S. Antohe
- grid.5100.40000 0001 2322 497XFaculty of Physics, University of Bucharest, Atomiștilor 405, 077125 Măgurele, Ilfov Romania ,grid.435118.a0000 0004 6041 6841Academy of Romanian Scientists (AOSR), Splaiul Independenței 54, 050094 Bucharest, Romania
| | - C. Negrila
- grid.443870.c0000 0004 0542 4064National Institute for Materials Physics, PO Box MG 7, 077125 Măgurele, Ilfov, Romania
| | - C. Logofatu
- grid.443870.c0000 0004 0542 4064National Institute for Materials Physics, PO Box MG 7, 077125 Măgurele, Ilfov, Romania
| | - A. Pérez del Pino
- grid.435283.b0000 0004 1794 1122Instituto de Ciencia de Materiales de Barcelona, Consejo Superior de Investigaciones Científicas (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Barcelona Spain
| | - E. György
- grid.435167.20000 0004 0475 5806National Institute for Lasers, Plasma and Radiation Physics, PO Box MG 36, 077125 Măgurele, Ilfov Romania ,grid.435283.b0000 0004 1794 1122Instituto de Ciencia de Materiales de Barcelona, Consejo Superior de Investigaciones Científicas (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Barcelona Spain
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Green Synthesis of Silver Oxide Microparticles Using Green Tea Leaves Extract for an Efficient Removal of Malachite Green from Water: Synergistic Effect of Persulfate. Catalysts 2023. [DOI: 10.3390/catal13020227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The removal of water pollutants by photocatalysis is a promising technique, mainly due to its environmentally friendly and sustainable nature. In this study, the degradation of a recalcitrant organic pollutant, malachite green (MG), was investigated in water by a microstructured silver oxide photocatalyst. The silver oxide (Ag2O) microparticles (MPs) were synthesized by a low-cost, green method, mediated by green tea leaves extract. The surface, morphological and optical properties of the synthesized Ag2O MPs were determined by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, and ultraviolet-visible (UV-visible) spectrophotometry. The synthesized Ag2O MPs showed good photoactivity, represented by 83% degradation of malachite green (MG) ([C]0 = 0.4 mM, Ag2O loading = 0.1 g L−1) at neutral pH, in 3 h. Persulfate ions (PS) showed a strong synergistic effect on the efficiency of solar/Ag2O photocatalysis, represented by complete MG removal in 15 min, in the presence of 1.6 mM PS. The results revealed that solar/Ag2O, particularly solar/Ag2O/PS photocatalysis is a promising method for the elimination of toxic organic pollutants, such as malachite green, from the water environment.
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Sapińska D, Adamek E, Masternak E, Zielińska-Danch W, Baran W. Influence of pH on the Kinetics and Products of Photocatalytic Degradation of Sulfonamides in Aqueous Solutions. TOXICS 2022; 10:655. [PMID: 36355946 PMCID: PMC9695452 DOI: 10.3390/toxics10110655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/19/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
The aims of the study were to determine the kinetics of the photocatalytic degradation of six sulfonamides in the presence of TiO2-P25 in acidic, neutral, and alkaline solutions and to identify the structures of the stable products. It was stated that the pH of the solution significantly affected the photocatalytic degradation rate of sulfonamides in acidic and alkaline environments, and the effect likely depended on the susceptibility of sulfonamides to attack by hydroxyl radicals. In the post-reaction mixture, we identified the compounds resulting from the substitution of the aromatic rings with a hydroxyl group; the amide hydrolysis products; the hydroxylamine-, azo, and nitro derivatives; and the compounds formed via the elimination of the sulfone group. Moreover, previously unknown azo compounds were detected. Some degradation products of sulfonamides may exhibit marked bacteriostatic activity and high phytotoxicity. The azo and nitro compounds formed in an acidic environment may be potentially more toxic to aquatic ecosystems than the initial compounds.
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Synthesis, Characterization, and Solar Photo-Activation of Chitosan-Modified Nickel Magnetite Bio-Composite for Degradation of Recalcitrant Organic Pollutants in Water. Catalysts 2022. [DOI: 10.3390/catal12090983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Photocatalysis is a promising process for decomposing harmful organic pollutants in water. In this study, solar/photocatalytic degradation of two model azo dyes, i.e., methylene blue (MB) and methyl red (MR), in water usinga nanostructured chitosan-modified nickel magnetite (CS-NM) bio-composite was investigated. The CS-NM bio-composite was synthesized through a co-precipitation method and characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), thermogravimetry (TGA), and UV-Vis spectroscopy. FTIR analysis showed the uniform incorporation and conjugation of nickel magnetite (NM) into the chitosan (CS) polymer matrix. SEM showed that the average particle size was 0.5 μm. The TGA results revealed the good thermal stability of the prepared bio-composite at 300 °C. The point of zero charge was calculated as 7.5. The effect of water quality and process parameters, such as concentration of dyes, catalyst dose, solution pH, and temperatures, was investigated, for application purposes. The solar/CS-NM photocatalysis resulted in 99 and 96% degradation of individual MB and MR (C0 = 50 ppm), respectively, in 90 min. The degradation of MB and MR by solar/CS-NM photocatalysis followed pseudo-first-order kinetics, with observed rate constants (k) of 0.077 and 0.072 min−1, respectively. The CS-NM photocatalyst showed high recyclability, represented by only a 4–6% loss in the photocatalytic efficiency, after four cycles. The results showed that solar/CS-NM photocatalysis is an efficient technique for degrading recalcitrant organic pollutants, such as azo dyes, in water environments.
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Photodegradation and Mineralization of Phenol Using TiO2Coated γ-Al2O3: Effect of Thermic Treatment. Processes (Basel) 2022. [DOI: 10.3390/pr10061186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
It is well-known that γ-Al2O3 possesses large, specific areas and high thermal, chemical, and mechanical resistance. Due to this, it is the most-used support for catalysts, in this case TiO2, as it enables it to achieve better dispersion and improves the activity in catalytic photodegradation reactions. In a previous work, it was observed that the optimal content of TiO2 in γ-Al2O3 was around 15% since the degradation of phenol results were maximized and a synergistic effect was generated by the interaction of both oxides. In addition, an increase in acidity crystal size and the generation of localized, oxygen-vacant, electronic states in the forbidden band of γ-Al2O3, were observed. This study focuses on the effect of the calcination temperature on a γ-Al2O3-TiO2 catalyst (15% w/w of TiO2) and its impact on photocatalytic activity. The catalysts prepared here were characterized by X-ray diffraction, N2 adsorption–desorption, FTIR-pyridine adsorption, MAS-NMR, HRTEM-FFT, UV-vis, and fluorescence spectroscopy.
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