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Synthesis of immobilized cerium doped ZnO nanoparticles through the mild hydrothermal approach and their application in the photodegradation of synthetic wastewater
摘要： The difficulty associated with accessing water resources, wastewater treatment and recycling are crucial subjects of research. In this regards the present research focuses on the synthesis, characterization, and photodegradation of synthetic wastewater by immobilized cerium doped ZnO nanoparticles. This was an experimental study at laboratory scale. The nanoparticles were synthesized through the mild hydrothermal technique and characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive spectroscopy (EDS), and Photoluminance analyses (PL). In addition, a reactor was designed and constructed for the photodegradation of the synthetic beverage effluent at laboratory scale. The fabricated nanoparticles were fixed on sand-blast glasses. The experiments were conducted by examining the parameters of doping percentage, pH, nanoparticle density, initial density of the wastewater sample, as well as exposure time to ultraviolet light and sunlight illumination. The doping molar percentage of cerium oxide in the photodegradation of the synthetic wastewater was shown to be effective, and the optimal percentage was observed at 1%. The results showed higher efficiency under the visible light illumination. Increasing the concentration of the effluent from 500 to 3000 mg/L resulted in the reduction of efficiency from 65.14 to 21.9 % under ultraviolet light and from 42.13 to 10.12% under visible light illumination. It was also found that increasing the exposure time would increase the efficiency of the wastewater photodegradation. The immobilized cerium doped zinc oxide nanoparticles showed excellent crystallinity and were well-dispersed.
关键词： Nanocatalysts,doping,immobilization,industrial wastewater,sunlight.
更新于2025-09-23 15:23:52
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Ag-graphene/PEG composite phase change materials for enhancing solar-thermal energy conversion and storage capacity
摘要： In view of the excellent characteristic of thermal energy storage, phase change materials (PCMs) are of great significance for improving the efficiency of solar thermal energy utilization. However, the direct thermal effect of visible-light (40% of solar radiation) is very low. In order to improve the capabilities of visible-light absorption and photothermal conversion, we reported novel and efficient sunlight-driven PCMs based on polyethylene glycol (PEG) supported by Ag nanoparticle-functionalized graphene nanosheets (Ag–GNS). The multifolded layered structure provides Ag–GNS a large surface area to support PEG for achieving the shape stability before and after phase transition. Meanwhile, based on the local surface plasma resonance effect of Ag, Ag has high visible light selective absorption and infrared reflectance, which can give Ag–GNS enhanced light absorption capacity and reduced thermal radiation. So Ag–GNS/PEG can harvest sunlight and convert light to thermal energy with significantly higher efficiency (η = 88.7–92.0%). Moreover, Ag–GNS/PEG composites exhibit enhanced thermal conductivities (49.5–95.3%), high energy storage densities (> 166.1 J/g), high thermal energy storage/release rates and outstanding form-stable properties. Therefore, this novel sunlight-driven composite can be potentially used for clean and efficient utilization of solar energy.
关键词： Sunlight-driven,Photothermal conversion,Phase change materials,Ag–GNS
更新于2025-09-23 15:23:52
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In situ anion exchange strategy to construct flower-like BiOCl/BiOCOOH p-n heterojunctions for efficiently photocatalytic removal of aqueous toxic pollutants under solar irradiation
摘要： The poor charge separation of single-component semiconductor photocatalysts greatly restrains their practical application. Herein, we report an in situ anion-exchange strategy to controllably fabricate sunlight-driven p-n heterostructure photocatalyst BiOCl/BiOCOOH. In this synthetic process, the BiOCOOH microspheres not only act as the support to form heterostructures but also as Bi3+ supplier to generate BiOCl. Such an in situ anion-exchange route thus brought about the homogeneous distribution of BiOCl on the surface of BiOCOOH with tight interfacial contact. Under simulated solar illumination, the obtained BiOCl/BiOCOOH catalysts with p-n heterostructures show exceedingly superior photocatalytic activity against toxic pollutant (MO dye and TC antibiotic) to BiOCOOH and BiOCl. The optimal BiOCl/BiOCOOH, S3 sample has the highest photocatalytic activity with MO degradation rate constant of 0.0599 min?1, 2.9 or 9.7 folds higher than that of BiOCOOH or BiOCl. The alleviated charge separation and transfer as well as the flower-like structure mainly account for the enhanced performance. Radical scavenging experiments indicate that holes, ?OH and ?O2? collaboratively contribute to the degradation of pollutants. This work provides a novel sunlight-driven p-n heterojunction photocatalyst of BiOCl/BiOCOOH for wastewater treatment.
关键词： Anion exchange,Sunlight,BiOCl/BiOCOOH,Photocatalysis,p-n heterojunction
更新于2025-09-23 15:23:52
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Association between sunlight exposure and risk of age-related macular degeneration: a meta-analysis
摘要： Background: A substantial number of epidemiological studies have investigated the possible associations between sunlight exposure and Age-related Macular Degeneration (AMD), but the results from studies are inconsistent. The aim of this meta-analysis was to evaluate the association between sunlight exposure and the risk of AMD. Methods: Relevant studies were searched using databases including PubMed, EMBASE, and Web of Science database. Two authors independently extracted data and assessed study quality. The random-effects model was used to calculate the pooled covariates-adjusted odds ratio (OR). Subgroup analyses based on study design, stage of AMD, method of exposure assessment, and study latitude were carried out. The heterogeneity across the studies was tested, as was publication bias. Results: Fourteen eligible studies including 43,934 individuals based on the inclusion criteria were analyzed. The pooled OR for sunlight exposure and AMD was 1.10 (95% CI = 0.98–1.23). In addition, similar insignificant results were observed in further subgroup analyses based on stage of AMD, method of exposure assessment, and study latitude. Sun-avoidance behavior did not decrease the risk of AMD (OR = 1.12, 95% CI = 0.76–1.67). Moderate heterogeneity was observed in most of analyses. Conclusion: The results indicate that sunlight exposure may not be associated with increased risk of AMD based on current published data.
关键词： Meta-analysis,Risk factor,Sunlight,Macular degeneration
更新于2025-09-23 15:22:29
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A Model Study of the Photochemical Fate of As(III) in Paddy-Water
摘要： The APEX (Aqueous Photochemistry of Environmentally-occurring Xenobiotics) software previously developed by one of us was used to model the photochemistry of As(III) in paddy-field water, allowing a comparison with biotic processes. The model included key paddy-water variables, such as the shielding effect of the rice canopy on incident sunlight and its monthly variations, water pH, and the photochemical parameters of the chromophoric dissolved organic matter (CDOM) occurring in paddy fields. The half-life times (t1/2) of As(III) photooxidation to As(V) would be ~20–30 days in May. In contrast, the photochemical oxidation of As(III) would be much slower in June and July due to rice-canopy shading of radiation because of plant growth, despite higher sunlight irradiance. At pH < 8 the photooxidation of As(III) would mainly be accounted for by reaction with transient species produced by irradiated CDOM (here represented by the excited triplet states 3CDOM*, neglecting the possibly more important reactions with poorly known species such as the phenoxy radicals) and, to a lesser extent, with the hydroxyl radicals (HO?). However, the carbonate radicals (CO3??) could be key photooxidants at pH > 8.5 provided that the paddy-water 3CDOM* is sufficiently reactive toward the oxidation of CO32?. In particular, if paddy-water 3CDOM* oxidizes the carbonate anion with a second-order reaction rate constant near (or higher than) 106 M?1·s?1, the photooxidation of As(III) could be quite fast at pH > 8.5. Such pH conditions can be produced by elevated photosynthetic activity that consumes dissolved CO2.
关键词： paddy-field floodwater,sunlight-induced reactions,arsenic contamination
更新于2025-09-23 15:22:29
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Co <sub/>3</sub> (PO <sub/>4</sub> ) <sub/>2</sub> /Ag <sub/>3</sub> PO <sub/>4</sub> with Enhanced Simulated Sunlight Photocatalytic Activity toward Ofloxacin Degradation and Mechanism Insight
摘要： BACKGROUND: Ofloxacin is a frequently detected fluoroquinolone antibiotic in wastewater treatment plants effluents, sea waters and surface waters. Photocatalytic technology is considered to the most promising treatment technology for the removal of ofloxacin. However, it is a big challenge to exploit the novel sunlight driven photocatalyst and reveal the mechanism of the ofloxacin degradation. RESULTS: Co3(PO4)2/Ag3PO4 composites were prepared using a facile hydrothermal synthesis method. The structural, morphological, optical properties of the composites were well characterized. Both the degradation efficiency and cyclical stability of the Co3(PO4)2/Ag3PO4 composites increased significantly under simulated sunlight irradiation, when ofloxacin (OFX) or methyl orange (MO) was used as the target molecule, as compared to single-phase Ag3PO4 and Co3(PO4)2. The reduction of antimicrobial activity for 8%Co3(PO4)2/Ag3PO4 reached to 88.8% after 5 min sunlight irradiation. CONCLUSIONS: Co3(PO4)2 played a critical role in suppressing carrier recombination and provided a large number of photogenerated holes and ?O2- to oxide OFX or MO. The OFX degradation mechanism included piperazinyl dealkylation, decarboxylation, defluorination. The reduction of antimicrobial activity for degradation byproducts was obvious after simulated sunlight irradiation over Co3(PO4)2/Ag3PO4. Therefore, Co3(PO4)2/Ag3PO4 is an attractive candidate for the removal of OFX.
关键词： Antibacterial activity,Mechanism,Ofloxacin,Co3(PO4)2/Ag3PO4,Simulated sunlight
更新于2025-09-23 15:22:29
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[IEEE 2018 VII. Lighting Conference of the Visegrad Countries (Lumen V4) - Trebic, Czech Republic (2018.9.18-2018.9.20)] 2018 VII. Lighting Conference of the Visegrad Countries (Lumen V4) - New Daylighting Metrics
摘要： Traditional daylighting metrics are gradually replaced by metrics based on absolute photometric parameters that are applied over the whole year. This process is at the stage of implementation in the design practice. The move to more realistic measures of daylighting is associated with a number of theoretical and practical problems. This article brings information about family of newly climate-based daylighting metrics that were developed in the world recently. The article also highlights some of the problematic aspects of climate-based daylighting metrics.
关键词： daylighting metrics,daylight autonomy,circadian light,climate-based daylight,sunlight
更新于2025-09-23 15:21:21
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Designed synthesis of microstructure and defect-controlled Cu-doped ZnO-Ag nanoparticles: exploring high-efficiency sunlight-driven photocatalysts
摘要： Cu-doped ZnO nanoparticles composited with Ag were synthesized by one-step sol-gel method in this work, aiming at highly photocatalytic activity and possible application under sunlight (especially near ultraviolet and visible light regions, 300-760 nm) irradiation. Scanning electron microscopy (SEM) shows that the introduction of Cu inhibits particle aggregation. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) reveal that Zn(Cu)O-Ag nanoparticles (CZA NPs) are composed of metallic Ag (Ag0) and Zn(Cu)O nanocrystals; while at the Cu concentration of higher than 2%, a little CuO nanocrystals appear. Transmission electron microscopy (TEM) results evidenced the well-defined formation of Zn(Cu)O-Ag and/or CuO-ZnO-Ag heterojunctions. UV–vis spectra display that the visible absorption of the samples is obviously enhanced after the Cu introduction. At a low Cu doping level (0.2%) and moderate Cu concentration (3~5%), the blue and green photoluminescence (PL) emission strength of the samples become very weak in comparison to other samples, indicative of the high separation of photogenerated electron-hole pairs. Reasonably, the higher photocatalytic degradation (complete degradation of methylene blue (MB) and methyl orange (MO) within 40 minutes under the simulated sunlight irradiation) are achieved in these cases: low Cu doping level (0.2%) and moderate Cu concentration (3~5%) in CZA NPs. Further, we checked the effects of other factors on the photocatalytic degradation for possible application. Our results suggest that one well-designed composite type such as element-doped Zn(M)O-Ag nano-heterojunction or complicated metal oxide-ZnO-Ag nanocomposites possessing suitable band structures for the separation and utilization of photo-generated carriers, will remarkably improve the photocatalytic performance of nano-ZnO under sunlight irradiation.
关键词： ZnO-Ag nanocomposites,heterojunction,sunlight irradiation,Cu-doped ZnO,photocatalytic degradation
更新于2025-09-23 15:19:57
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ZIF-8 derived ZnO/Zn6Al2O9/Al2O3 nanocomposite with excellent photocatalytic performance under simulated sunlight irradiation
摘要： In this contribution, ternary ZnO/Zn6Al2O9/Al2O3 nanocomposite was obtained by in situ incorporation of Al3+ during the synthesis of ZIF-8, aiming to improve the adsorption and photocatalytic performance of ZIF-8-derived ZnO under simulated sunlight irradiation. XRD, SEM, TEM, HRTEM, XPS, UV-Vis DRS, BET and PL techniques were employed for the analysis of the crystalline structure, composition, morphology, light absorption and charge separation of the samples. The photocatalytic activity of the samples was evaluated by the degradation of Methyl orange (MO) under simulated sunlight irradiation. Compared to ZIF-8-derived ZnO, the formation of ZnO/Zn6Al2O9/Al2O3 nanocomposite can provide with high BET specific surface area, reduce the band gap, inhibit the recombination of the electron-hole pairs, and hence greatly improve the photocatalytic activity. The maximum photocatalytic degradation rate of 97.5% for a high initial MO concentration of 150 mg/L-1 was obtained over ZnO/Zn6Al2O9/Al2O3 nanocomposite with molar ratio of Al/Zn as 1:1 under simulated sunlight irradiation for 60 min, which is 3.18 times higher than that of ZIF-8-derived ZnO.
关键词： Zn6Al2O9,Simulated sunlight irradiation,Al2O3,ZIF-8,ZnO,Photocatalytic degradation
更新于2025-09-19 17:15:36
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Sunlight-induced photocatalytic degradation of acetaminophen over efficient carbon doped TiO2 (CTiO2) nanoparticles
摘要： Carbon doped titanium oxide (CTiO2) photocatalyst was successfully synthesized by the sol–gel method. The crystal structure, surface morphology, and optical properties of CTiO2 have been characterized by X-ray diffraction, Brunauer–Emmett–Teller surface area (SBET), scanning electron microscope, UV–Vis, X-ray spectroscopy (EDS), Fourier transform infrared and X-ray photoelectron spectroscopy. The photocatalytic degradation of acetaminophen (AMP) in aqueous solution, seawater, and polluted seawater has been investigated by using the synthesized photocatalyst under irradiation of UV and natural sunlight. The effectiveness of CTiO2 compared to pure TiO2 toward the photocatalytic removal of AMP was significantly observed. The optimized conditions including catalyst dose, initial concentration of AMP and solution pH were also studied for effective photocatalytic removal. The highest degradation rate was obtained when 2.0 g L?1 of the catalyst was used at pH 7. The kinetic results revealed that the photocatalytic degradation of AMP using CTiO2 obeyed a pseudo-first-order reaction kinetics.
关键词： Photocatalytic degradation,Seawater,CTiO2,Nanoparticles,Acetaminophen,Sunlight
更新于2025-09-19 17:15:36