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An anti-symmetric dual (ASD) Z-scheme photocatalytic system: (ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4) for organic pollutants degradation with simultaneous hydrogen evolution
摘要: An anti-symmetric dual (ASD) Z-scheme ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4 photocatalyst was prepared by isoelectric point and calcination methods. The photocatalytic activity is estimated via degradation of Acid Orange II as a target organic contaminant with simultaneous hydrogen evolution under simulated solar-light irradiation. The prepared ASD Z-scheme ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4 photocatalyst has a high photocatalytic activity, which can be assigned to the enlarged photoresponse range, increased reduction surface and enhanced separation efficiency of photo-induced carriers. Furthermore, the cyclic experiment proves that the prepared ASD Z-scheme ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4 photocatalyst still maintains a high photocatalytic activity within five repetitive cycles. Moreover, the mechanism on photocatalytic degradation of organic pollutants with simultaneous hydrogen evolution caused by ASD Z-scheme ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4 photocatalyst is proposed. It is wished that this study could provide a promising pathway for effective degradation and rapid hydrogen production.
关键词: Simultaneous hydrogen evolution,Organic contaminants,Anti-symmetric dual (ASD) Z-scheme photocatalytic system,ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4 composite,Up-conversion luminescence agent,Photocatalytic degradation
更新于2025-11-19 16:51:07
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One-pot self-assembly of 3D CdS-graphene aerogels with superior adsorption capacity and photocatalytic activity for water purification
摘要: Graphene-based three-dimensional (3D) aerogel hybrids have recently emerged as a new class of functional materials and applied in many fields. In this work, we assemble the spherical CdS nanoparticles in situ in graphene aerogel (GA) by a facile one-pot hydrothermal method. The resultant CdS-GA hybrids possess a hierarchical porous structure and there is strong electronic interaction between CdS and GA, which enhances the adsorption capacity and photocatalytic activity for the elimination of organic contaminants in water under visible light irradiation, such as rhodamine B (RhB), methylene blue (MB), acid chrome blue K (AcbK), methyl orange (MO), and ciprofloxacin (CIP). The removal efficiencies of CdS-GA for MO, MB, CIP, RhB, AcbK are 15.6, 6.6, 4.4, 2.8, and 2.2 times of pure CdS, respectively. Meanwhile, the resultant CdS-GA hybrids display good reusability. In addition, a photocatalytic mechanism is also discussed. This provides a valuable alternative to explore semiconductor-GA hybrids with outstanding adsorption capacity and superior visible-light induced photocatalytic activity.
关键词: Graphene aerogel,Adsorption,Photocatalysis,Hybrids,CdS nanoparticle,organic contaminants
更新于2025-09-23 15:23:52
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Efficiency of sequential UV/H2O2 and biofilm process for the treatment of secondary effluent
摘要: In response to the shortage of water resources, multiple processes have been applied to turn wastewater secondary effluent (SE) into potable water. However, trace organic contaminants (TOrCs) and high concentrations of organic matter contained in SE pose a significant challenge to the reclamation. In this manuscript, combined UV-based and biofilm processes were used to treat the SE spiked with ibuprofen (IBU) and clofibric acid (CA). The efficiency of these sequential treatments was characterized in terms of changes in dissolved organic carbon (DOC), absorbance at 254 nm (A254), fluorescence excitation-emission matrix (FEEM), the concentration of IBU and CA, and molecular weight of SE. Parallel factor (PARAFAC) was applied as the analysis method for FEEM of the samples and two fluorescent components were successfully identified: humic-like substances (C1) and protein-like matter (C2). Large reductions in A254, C1, C2, IBU, and CA were observed during the UV-based processes, especially with the addition of H2O2. Nearly 50% of A254, 80% of the component C1 were decreased and almost complete removal of the component C2 and TOrCs was achieved by UV/2.0 mM H2O2 after 90-min treatment. During the oxidation processes, the formation of lower molecular weight (LMW) compounds was detected, and the biodegradability of the organic matters was greatly increased. Although no significant DOC reduction was obtained in UV-based processes, an obvious further DOC reduction (30~60%) was achieved by biofilm treatment following UV-based processes, especially after UV/H2O2 treatments. In the meantime, large amounts of LMW were removed in the biofilm treatment process. This manuscript provides an effective advanced treatment of SE for the removal of DOC and TOrCs, facilitating the wastewater reclamation.
关键词: Trace organic contaminants,Removal,Biofilm,Secondary effluent,Dissolved organic carbon,UV/H2O2
更新于2025-09-23 15:21:21
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The effect of manganese doping on structural, optical, and photocatalytic activity of zinc oxide nanoparticles
摘要: In this work, polyethylene glycol-6000 (PEG-6000) capped ZnO nanoparticles (NPs) were synthesized by doping with varying levels of Mn (0, 1, 2, 3, and 4 wt.%; 0% implies no doping). The crystalline sizes of the hexagonal wurtzite-structured nanoparticles, when measured with (4%) and without Mn doping (0%), were 30 and 28 nm, respectively. The Mn doping led to a shift of the ZnO optical band gap from 3.36 to 3.51 eV. The Mn2+ ions from the doping agent caused tail states in the absorbance spectrum of ZnO NPs, allowing them to be used as effectual UV photocatalysts for the degradation of organic contaminants (e.g., methyl orange (MO), methylene blue (MB), and congo red (CR)). This effect was optimized when doped with 4% Mn. When comparing 0 and 4% Mn doping, the degradation efficiency of the three contaminants was approximately 87/93.5 (MO), 85/88 (MB), and 86/93 (CR)%, respectively. Accordingly, Mn doping on ZnO NPs was found to significantly enhance their photo-degradation efficiency.
关键词: Mn-ZnO,photocatalytic degradation,organic contaminants,UV irradiation,semiconductor nanoparticles
更新于2025-09-10 09:29:36
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Recyclable Visible Light-driven O-g-C3N4/GO/N-CNT Membrane for Efficient Removal of Organic Pollutants
摘要: Organic pollutants are harmful to human health, which creates a global need for the development of novel and effective materials for efficiently removing contaminants. Accordingly, the efficient visible light-driven heterostructured membrane combined with oxygen-modified monolayer g-C3N4, graphene oxide, and nitrogen-doped CNT (O-g-C3N4/GO/N-CNT) was successfully fabricated through electrostatic interactions and subsequent vacuum filtration. The results suggested that the O-g-C3N4/GO/N-CNT membrane exhibited higher degradation rate than that of O-g-C3N4/GO and pure O-g-C3N4 under visible-light exposure. This enhanced photocatalytic performance was attributed to the introduction of GO and N-CNT, which acted as electronic acceptors for monolayer O-g-C3N4 that effectively inhibited recombination of photogenerated electron-hole pairs, thus enhancing visible light photocatalytic activity. Furthermore, the enrichment and degradation rate of O-g-C3N4/GO/N-CNT membranes were demonstrated for tetracycline hydrochloride, which was found up to 96.64% and 94.30%, respectively, and no distinct enrichment or catalytic activity reduction was observed when their reusability was measured. These results suggested that these recyclable O-g-C3N4/GO/N-CNT membranes provide a new strategy for the highly efficient removal of environmental pollutants.
关键词: O-g-C3N4/GO/N-CNT heterostructured membrane,Organic contaminants,Recyclable,Enhanced Photocatalytic performance,Enrichment
更新于2025-09-10 09:29:36
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Oxygen Vacancy-Rich Ultrathin Sulfur-Doped Bismuth Oxybromide Nanosheet as a Highly Efficient Visible-Light Responsive Photocatalyst for Environmental Remediation
摘要: Designing ultrathin two-dimensional (2D) defective materials and metal-free doped materials as photocatalysts both have received enormous attentions in the field of environmental remediation due to their great potential for removing colorless contaminants. However, whether the synergism of defects and metal-free doping exists and the corresponding oxidative mechanism is unclear, which retard further developments of high performance catalysts. Here, a novel oxygen vacancy (OV)-rich ultrathin sulfur-doped BiOBr nanosheet (BB-xS) was synthesized through a facile one-step solvothermal method. Under visible light irradiation, the optimal BB-5S sample exhibited 98% degradation efficiency of 4-chlorophenol (4-CP) within 120min, which was 4.9 and 18.0 times greater than that of pristine ultrathin BiOBr and oxygen vacancy-poor sulfur-doped BiOBr, respectively. Also, this excellent photoactivity could extend to other colorless organic contaminants, such as bisphenol analogues and sulfonamides, verifying the universal applicability of BB-xS. Based on experimental results and density functional theory (DFT) calculations, it was manifested that a sub-band was generated via the synergistic effect of oxygen vacancies and sulfur doping, and it greatly enhanced the visible-light absorption capability and suppressed the photoinduced charge recombination, which would be beneficial to improve the photocatalytic activity. Additionally, the corresponding photocatalytic degradation pathway of 4-CP was also proposed. This work can provide a new protocol for the design and construction of highly active photocatalysts toward environmental remediation.
关键词: photocatalytic degradation,Ultrathin two-dimensional nanosheets,sulfur-doped,oxygen vacancy,colorless organic contaminants
更新于2025-09-09 09:28:46