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Photocatalytic and Photo-Fenton Catalytic Degradation Activities of Z-Scheme Ag2S/BiFeO3 Heterojunction Composites under Visible-Light Irradiation
摘要： Z-scheme Ag2S/BiFeO3 heterojunction composites were successfully prepared through a precipitation method. The morphology and microstructure characterization demonstrate that Ag2S nanoparticles (30–50 nm) are well-decorated on the surfaces of polyhedral BiFeO3 particles (500–800 nm) to form Ag2S/BiFeO3 heterojunctions. The photocatalytic and photo-Fenton catalytic activities of the as-derived Ag2S/BiFeO3 heterojunction composites were evaluated by the degradation of methyl orange (MO) under visible-light irradiation. The photocatalytic result indicates that the Ag2S/BiFeO3 composites exhibit much improved photocatalytic activities when compared with bare Ag2S and BiFeO3. The optimum composite sample was observed to be 15% Ag2S/BiFeO3 with an Ag2S mass fraction of 15%. Furthermore, the addition of H2O2 can further enhance the dye degradation efficiency, which is due to the synergistic effects of photo- and Fenton catalysis. The results of photoelectrochemical and photoluminescence measurements suggest a greater separation of the photoexcited electron/hole pairs in the Ag2S/BiFeO3 composites. According to the active species trapping experiments, the photocatalytic and photo-Fenton catalytic mechanisms of the Ag2S/BiFeO3 composites were proposed and discussed.
关键词： polyhedral BiFeO3 particles,photo-Fenton catalysis,Ag2S nanoparticles,photocatalysis,Z-scheme Ag2S/BiFeO3 heterojunction
更新于2025-11-19 16:46:39
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Interesting makeover of strontium hexaferrites for environment remediation from excellent photocatalysts to outstanding adsorbents via inclusion of Mn3+ into the lattice
摘要： Manganese incorporated strontium hexaferrites with composition SrMnxFe12-xO19 (x= 0.0, 0.4, 0.8, 1.2, 1.6, 2.0, 3.0, 4.0 and 5.0) were fabricated via chemical co-precipitation methodology. Various characterization techniques were employed to investigate the physical properties of the synthesized hexaferrites. Powder X-Ray Diffraction (XRD) patterns revealed the formation of hexagonal phase with P63/mmc space group. FE-SEM micrographs exhibited hexagonal morphology of the synthesized materials; particle size of 125-150 nm range was observed. EDX spectra unveiled the presence of desired elements. The lattice interplanar fringe width from HR-TEM images was observed to be 0.22 nm, 0.26 nm and 0.27 nm indexed to (114), (107) and (203) planes of the manganese doped strontium hexaferrite. Surface area of the synthesized hexaferrites was found to be in the range of ~7.8 to ~8.4 m2/g, scrutinized by Brunauer–Emmet–Teller (BET) plots. Saturation magnetisation values were found to decrease with increase in Mn content from 38.7 to 11.7 emu/g, albeit retaining sufficient magnetic strength to be recovered using an external magnet. Absorption edge for all the hexaferrites was found to lie in the visible region of the spectrum. The oxidation state of different elements present in synthesized hexaferrites was scrutinized using X- ray Photoelectron Spectroscopy (XPS). To explore the catalytic efficiency of the synthesized hexaferrites, photo-fenton degradation of methyl orange (MO), remazol deep red (RDR) and p-nitrophenol (PNP) was employed. All the synthesized hexaferrites were found to be highly proficient, degrading the pollutants upto ~98%. Interestingly, astonishing adsorption of ~92.7 % was showcased by SrMn5Fe7O19, prior to the addition of oxidizing agent indicating the symptomatic transformation from excellent photocatalyst to outstanding adsorbents via incorporation of Mn3+ into the lattice. The maximum adsorption capacity of 56.20 and 112.35 mg/g was observed for MO and RDR, respectively.
关键词： photo-fenton degradation,strontium hexaferrites,adsorption,chemical co-precipitation method,manganese substituted ferrites
更新于2025-11-14 17:03:37
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Efficient photo-Fenton activity in mesoporous MIL-100(Fe) decorated with ZnO nanosphere for pollutants degradation
摘要： Metal-organic frameworks (MOFs) have received significant interest as a promising photocatalyst for environmental remediation due to its high surface area and porous nature. The small pores (<2 nm) in microporous MOFs help the adsorption of small molecules but limits diffusion and accessing of bigger molecules from MOF cavities, thus preventing their applications in some situation. The aim of this work is to fabricate mesoporous MOF composite with larger pore sizes (>2 nm) and open pore cavities that can provide right pathways for ingoing and outgoing of molecules during catalysis. Herein, we successfully report stable mesoporous MIL-100(Fe) loaded with ZnO NS by an in situ self-assembly method. The prepared samples were characterized by Brunauer–Emmett–Teller (BET) and N2 adsorption-desorption isotherm to study their surface area and porosity. The catalytic performance of mesoporous MIL-100(Fe) was approximately 2-3 order of magnitude more than that of microporous MIL-100(Fe). Such higher catalytic activity in mesoporous MIL-100(Fe) can be ascribed to its mesocellular structure which can improve the molecular diffusion and accessibility inside MOF channels. The charge separation efficiency and photo-Fenton activity of mesoporous MIL-100(Fe) can further be increased by introduction of certain amount of ZnO NS and H2O2. Moreover, the as synthesized sample shows higher photo-Fenton degradation efficiency at lower pH value with certain amount of H2O2. Lastly, the possible catalytic mechanism has been tentatively proposed. This study not only used for the pollutants degradation but also provide useful platform for the application of mesoporous MOFs as an efficient photo-Fenton activity to various other fields.
关键词： Metal-organic framework,ZnO,MIL-100(Fe),self-assembly,photo-Fenton,mesoporous
更新于2025-09-23 15:23:52
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TiO2/Schwertmannite nanocomposites as superior co-catalysts in heterogeneous photo-Fenton process
摘要： The heterogeneous photo-Fenton reaction is an effective technique in combating organic contaminants for both soil and water remediation, and extensive studies have focused on enhancing its efficiency and reducing its costs. In this work, we developed novel photo-Fenton catalysts by simply milling commercially available TiO2 (P25) with Schwertmannite (Sh), a natural iron-oxyhydroxysulfate nanomineral. We expect that the photo-generated electrons from TiO2 could continuously migrate to Sh, which then could enhance the separation of electron-hole pairs on TiO2 and accelerate the reduction of Fe(III) to Fe(II) on Sh, leading to high degradation efficiency of the target organic contaminants. SEM and TEM results showed the distribution of TiO2 on Sh surface for the nanocomposites (TiO2/Sh). Under simulated sunlight irradiation, the much higher content of Fe(II) was determined on TiO2/Sh than on Sh via a common method in the iron ore, and the consumption of H2O2 and the production of ?OH were more significant in the TiO2/Sh system than those in the TiO2 and Sh systems. These results well support our hypothesis that the photo-generated electrons could migrate from TiO2 to Sh on the composites, and can also explain the much higher degradation efficiency of Rhodamine B (RhB) in the TiO2/Sh system. Besides, TiO2/Sh had lower Fe dissolution as compared with Sh, and retained high catalytic stability after four repeated cycles. Above merits of the TiO2/Sh composites, in combining with their simple synthesis method and low-cost property, indicated that they should have promising applications as heterogeneous photo-Fenton catalysts.
关键词： Advanced oxidation,Photo-Fenton reaction,Semiconductor,Schwertmannite
更新于2025-09-23 15:23:52
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Mg dependent Sunlight photocatalytic performance of Nickel ferrite synthesized by a green sol-gel route
摘要： We report an environmentally friendly synthetic strategy to synthesize new nickel ferrite and Mg doped nickel ferrite photocatalysts under modified green sol-gel route in which Aloe Vera gel acts as a natural template. The crystalline phase, surface morphology and size of the prepared photocatalysts were characterized by PXRD, SEM, TEM and HRTEM analysis. The energy band gap of the nanoparticles (NPs) can be tuned in the range of 2.55–2.34 eV by varying the dopant concentration. The photoluminescence analysis indicates that the present NPs are an effective white component in display applications. These synthesized NPs were used for photocatalytic decomposition of recalcitrant pollutants in aqueous media under Sunlight irradiation. When compared to pure, NiFe2O4: Mg2+ (5 mol %), the NiFe2O4: Mg2+ (1mol %) exhibits the highest photocatalytic efficiency for the decomposition of recalcitrant pollutants than that of commercial P25.This enhancement in photocatalytic performance can be mainly attributed to the balance between the parameters, crystallanity,band gap, morphology, crystallite size, defects, dopant amount and combined facets of photocatalysis It opens new window to use this simple greener route to synthesize bi-functional character NPs in the area of photocatalysis particularly waste water treatment and display applications.
关键词： Photo-Fenton catalytic performance,Photoluminescence,Green Sol-gel route,NiFe2O4:Mg2+NPs
更新于2025-09-23 15:23:52
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Heterogeneous degradation of organic contaminants in the photo-Fenton reaction employing pure cubic β-Fe2O3
摘要： Pure cubic β-Fe2O3 crystal, which can absorb visible light (< 650 nm) on account of the bandgap of 1.9 eV as a direct bandgap semiconductor, was employed as a low-cost and non-toxic catalyst for photo-Fenton reaction in this article. Diverse organic contaminants including rhodamine B (RhB), methyl orange (MO), alizarin red (AR) and phenol can be effectively degraded. In particular, the degradation of RhB were investigated detailedly. As such, hydroxyl radicals (%OH) were verified to act as considerable active species for the process by using terephthalic acid as an indicator. Degradation mechanism and intermediates of phenol in the photo-Fenton reaction was discovered by virtue of liquid chromatography-mass spectrometry (LCeMS). Notably, hydroxylation of phenol generated some intermediates, which are converted into H2O and CO2 eventually.
关键词： Photo-Fenton,H2O2,β-Fe2O3,Degradation,Hydroxyl radicals
更新于2025-09-23 15:22:29
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Preparation of Mesoporous Fe2O3-Supported ZSM-5 Zeolites by Carbon-Templating and their Evaluation as Photo-Fenton Catalysts to Degrade Organic Pollutant
摘要： Mesoporous Fe2O3-supported ZSM-5 zeolites were prepared by carbon-templating and subsequently evaluated as photo-Fenton catalysts to degrade a dye used as a model heavy organic pollutant. The synthesis procedure of the mesoporous ZSM-5 zeolites was performed employing a nucleating gel and carbon particles as mesopores template. Thereafter, the precursor salt of the iron oxide (Fe2O3) was impregnated and then calcined to obtain the final catalyst. For comparison purposes, a conventional Fe2O3-supported ZSM-5 zeolite was also prepared. The results showed that the amount of intracrystalline mesopores formed in the ZSM-5 crystals was influenced by the amount of carbon added into the synthesis mixture. In comparison to the conventional prepared catalyst, the mesoporous Fe2O3/ZSM-5 ones showed an improved performance in the degradation of the target organic pollutant by the photo-Fenton reaction, which was attributed to the improvement of their textural properties as consequence of the mesopores generation.
关键词： Fe2O3-supported ZSM-5,Mesoporous ZSM-5,carbon template,dye degradation,photo-Fenton reaction
更新于2025-09-23 15:22:29
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Different approaches for the solar photocatalytic removal of micro-contaminants from aqueous environment: Titania vs. hybrid magnetic iron oxides
摘要： This work reports on the light-induced heterogeneous photodegradation of four micro-contaminants (MCs): Carbamazepine (C), Flumequine (F), Ibuprofen (I), and Sulfamethoxazole (S), using two different heterogeneous advanced oxidation processes. The first one is the semiconductor photocatalysis, run in the presence of the suspension of a home prepared TiO2 (TiO2 HP); the second one is an heterogeneous photo-Fenton process run in the presence of a hybrid magnetic nanomaterial (MB3) with an iron oxides core and an organic shell made of bio-based substances (BBS) isolated from urban biowaste. The two materials work upon two different mechanisms and were already tested (and the action mechanism hypothesized) at the lab scale under model conditions: TiO2 acts as photocatalyst through the photo-generation of hole/electron pairs able to give rise to oxidation and reduction reactions, whereas hybrid magnetic nanomaterial acts in the presence of H2O2 by a photo-Fenton like mechanism. The results evidenced the better performances of TiO2 HP (also better than the well-known reference TiO2 P25). Preliminary photodegradation experiments carried out in a pilot plant under natural solar radiation confirmed the good results obtained with TiO2 HP. Moreover, in the adopted experimental conditions, the Fe(II) leached from MB3 can be considered as responsible of the MCs degradation through a homogeneous photo-Fenton reaction, where MB3 act as iron reservoir.
关键词： TiO2,Micro-contaminants,Photo-Fenton,Photocatalysis,Water treatments,Magnetic materials.
更新于2025-09-23 15:22:29
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Paracetamol mineralization by Photo Fenton process catalyzed by a Cu/Fe-PILC under circumneutral pH conditions
摘要： This study presents an iron-pillared clay (Fe-PILC) ion-exchanged with copper (Cu/Fe-PILC), as an efficient catalyst to conduct the mineralization of paracetamol through photo-Fenton process at near to neutral pH without precipitation of Fe complexes and without adding any chemicals to modify the initial pH. The specific surface area of the catalyst was of 110 m2 g-1 and with the following phases FeO, Fe3O4, Cu2O, CuO determined by XPS analyses. Around 80% of mineralization was reached either by conducting the process at acidic and circumneutral pH conditions, and the efficiency was not significantly higher at pH = 2.7. The intermediate reaction products generated at both pH conditions essayed and detected by LC–MS were hydroquinone, acetamide and oxamic acid. Catalyst Cu/Fe-PILC showed an iron leaching of about 3% after reaction while the reusability of the catalyst involved a decrease in mineralization of only 3% under circumneutral conditions. The final TOC of about 20% can be ascribed to the presence of acetamide that was found to be the most reluctant towards oxidation.
关键词： Pillared clays,Paracetamol,Photo-Fenton
更新于2025-09-23 15:22:29
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Enhanced photocatalytic inactivation of E.coli by natural pyrite in presence of citrate and EDTA as effective chelating agents: Experimental evaluation and kinetic and ANN models
摘要： The effect of chelating agents (citrate and EDTA) on the visible light photocatalytic activity of natural pyrite for the inactivation of Escherichia coli ATCC 25922 (E.coli) was investigated. The influence of various parameters, such as chelating agent and H2O2 concentration, light intensity and aeration rate, was evaluated experimentally and through kinetic models. The presence of a chelating agent enhanced the photocatalytic activity of natural pyrite, and citrate was more effective than EDTA, considerably improving bacteria inactivation in natural pH and reducing the drawbacks of the photocatalytic inactivation system. For both citrate-pyrite and EDTA-pyrite, the inactivation rate went through a maximum for a concentration of the chelating agent of 0.5 mM. The increase of the light intensity (10–60 mW cm-2), H2O2 concentration (10-25 mg L-1) and aeration rate (2-8 L min-1) improved the radical generation, resulting in a high inactivation effect. The low effect of H2O2 on the catalytic activity of pyrite in the presence of EDTA was likely due to the inhibition of the hydrogen peroxide-to-hydroxyl radical conversion by EDTA. On the other hand, degradation of citrate at high aeration rate occurred, decreasing the catalytic activity of the citrate-pyrite system. Scavenging tests indicated that the bulk hydroxyl radicals are the most reactive radical species in the bacterial inactivation, closely followed by valence band holes, while conduction band electrons play a less important role. In addition, in order to generate predictions and to better understand the process, artificial neural networks were used as models for the considered process: the obtained performance indexes indicated a good correlation between experimental and predicted values.
关键词： Pyrite,Photo-Fenton,E.coli,Photocatalytic inactivation,Chelating agents
更新于2025-09-23 15:22:29