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A critical review on visible-light-response CeO2-based photocatalysts with enhanced photooxidation of organic pollutants
摘要： Organic pollutants’ treatment in wastewater has attracted extensive attention due to its degradation-resistance and potentially hazardous to human health. Some organic matters such as persistent organic pollutants (POPs) could exist in environment and resist to decomposition, which may cause chronic intoxication or even cancers. Because photocatalytic technique is efficient, nontoxic, and cost-effective to degrade organic pollutants, some semiconductors including TiO2 and ZnO as photocatalysts have aroused wide public concern. CeO2 has been reported as an efficient photocatalyst in contrast to TiO2 owing to its high oxygen storage, eco-friendly properties and photostability. But inefficient utilization of solar energy due to its intrinsic wide bandgap restrains its further application in real environmental pollutant treatment. In order to improve photocatalytic performances of CeO2, some modifications have been developed such as doping ions, coupling with semiconductor and construction of CeO2-based solid-solution. The purpose of this review is to introduce these techniques, reveals its fundamental mechanisms and the recent researches about photodegradation of organic pollutants in wastewater over CeO2-based photocatalysts. Besides, this review will evaluate the photocatalytic performance for organic pollutants and outlook the challenges and prospects in the future.
关键词： Modification,CeO2,Visible-light-response,Photodegradation,Organic pollutants
更新于2025-09-23 15:21:21
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Reduced graphene oxide supported MnO2 nanorods as recyclable and efficient adsorptive photocatalysts for pollutants removal
摘要： The emerging concept of two dimensional (2D) hybrid materials with large surface area and good interfacial contacts is highly desirable for diverse catalytic applications. Herein, we have designed and developed novel 1D-2D nanocomposite by loading manganese dioxide (MnO2) nanorods over reduced graphene oxide (RGO) nanosheets by facile hydrothermal synthesis method to exploit the large surface area, close contact of 1D-2D components with abundant reaction sites. The as prepared MnO2-RGO nanocomposite has been characterized in detail using state-of-art techniques and has been successfully utilized efficient adsorptive photocatalysts for the removal of a colored dye (neutral red) and a colorless pollutant (ciprofloxacin) from water. In addition, the stability and recyclability of this catalyst has also been demonstrated. This work is expected to pave way for the development of many new 1D-2D binary nanocomposite catalysts for environmental remediation applications.
关键词： Reduced graphene oxide,MnO2 nanorods,Photocatalysis,Pollutants removal,Ciprofloxacin,Neutral red
更新于2025-09-23 15:21:21
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Online Third-Order Liquid Chromatographic Data with Native and Photoinduced Fluorescence Detection for the Quantitation of Organic Pollutants in Environmental Water
摘要： Third-order liquid chromatographic data were generated online for the simultaneous quantitation of six organic environmental pollutants. The employed strategy consists in reducing the linear flow rate at the column outlet. A postcolumn UV reactor and a fluorimetric detector allowed to properly record both photoinduced and native excitation?emission fluorescence matrices (EEPIFMs and EEFMs, respectively). The obtained third-order liquid chromatography data were chemometrically processed with the multivariate curve resolution?alternating least-squares model. The sensitivity of the overall analytical method was enhanced by a very simple solid-phase extraction with C18 membranes, to be able to successfully apply it to natural water samples tested as real matrices. Favorable detection limits for the investigated pollutants, ranging from 0.02 to 0.27 ng mL?1, were attained, with relative prediction errors between 2 and 7%. Since the studied samples contain uncalibrated interferents, the applied strategy achieves the second-order advantage. Implications regarding the potential achievement of the third-order advantage are discussed.
关键词： multivariate curve resolution?alternating least-squares,solid-phase extraction,second-order advantage,third-order advantage,third-order liquid chromatographic data,photoinduced fluorescence detection,organic environmental pollutants
更新于2025-09-23 15:21:21
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Controlled synthesis of AgNPs@ZIF-8 composite: Efficient heterogeneous photocatalyst for degradation of methylene blue and congo red
摘要： Photocatalytic degradation of organic dyes using novel metal based composite materials is one of the most intriguing and sustainable ways to reduce water pollution. Herein, facile synthesis of AgNPs@ZIF-8 via in situ generation of AgNPs and ZIF-8 (Zeolitic Imidazolate Framework) was demonstrated, and composites with different Ag contents (abbreviated as SZ, SZ1, SZ2 SZ3) were well characterized by powder X-ray diffraction (PXRD) pattern, X-ray photoelectron spectroscopy (XPS) and Fourier transform infra-red (FT-IR) spectroscopy. Encapsulation/decoration of AgNPs (particle size: 96 nm in SZ and 17.32 ± 2.35 nm in SZ1 to SZ3) in ZIF-8 matrix has been ensured by TEM and EDX analysis. Brunauer-Emmett-Teller (BET) adsorption-desorption studies indicate that the surface area of SZ (982 m2 g?1) is less than those of SZ1 to SZ3 (due to the encapsulation of large amount of Ag nanoparticles in SZ). The synthesized composites are thermally stable up to 400 °C in air and nitrogen atmosphere. AgNPs@ZIF-8 exhibited excellent photocatalytic efficiency to degrade organic dyes compared to ZIF-8 due to its large surface area, highly porous and unique synergistic properties. SZ2 degrades off 97.25 % methylene blue (MB) and 100 % congo red (CR) at pH ≥ 7. Further, degraded fragments were analysed by GC–MS and plausible degradation mechanism was discussed.
关键词： Silver nanoparticles,Organic pollutants,Photocatalyst,Heterogeneous catalysis,Composite materials
更新于2025-09-23 15:21:01
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Towards Smart Selective Sensors exploiting a novel approach to connect Optical Fiber Biosensors in Internet
摘要： The selective detection of pollutants in water in a laboratory scenario has been presented by authors exploiting low-cost optical biosensors based on plastic optical fibers (POFs) and biological or bio-mimetic receptors. For instance, the detection in water of naphthalene, perfluoroalkyl and polyfluoroalkyl substances (PFAs) have been investigated with interesting detection limits when compared to those obtained by using different expensive traditional approaches (e.g. liquid chromatography-mass spectrometry with high performances). In this work, we have developed and tested a novel approach used in a smart measuring system to use POF sensors in situ for the remote measures of pollutants in water for smart cities applications. More specifically, we have used different water-glycerin solutions to test the novel sensor system based on a Raspberry PI connected to the Internet and to a spectrometer, a light source, a POF sensor, and two computers connected to Internet used as client and server.
关键词： optical fiber sensors,water quality,pollutants,software,biosensors,Plastic optical fibers (POFs),Internet of Things (IoT)
更新于2025-09-23 15:21:01
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FTO-TiO2 photoelectrocatalytic degradation of triphenyltin chloride coupled to photoelectro-Fenton: A mechanistic study
摘要： A powerful, simple and stable transparent photoanode based on TiO2 nanoparticles deposited on fluorine-doped tin oxide (FTO) was synthesized for the photoelectrocatalytic degradation of the organometallic pollutant triphenyltin chloride (TPTCl). Contrasting with most of the works on photoelectrocatalysis (PEC), FTO-TiO2 was found to be an excellent anode material for the degradation/mineralization of organic pollutants at high anodic potentials through the formation of electrochemically-induced hVB+ (dark PEC), showing a similar behavior as the so-called 'non-active' anodes like the powerful boron doped diamond electrode (BDD). The electrocatalytic efficiency was enhanced by the photoexcitation of TiO2 under UV light (PEC) and by coupling with photoelectro-Fenton (PEC-PEF): this resulted in complete degradation of TPTCl in 15 min (kapp = 0.274 min-1) and total mineralization in 2 h. The mechanisms governing the photoelectrocatalytic processes are investigated in detail by means of electrochemical measurements and chemical probes, and a mineralization pathway for TPTCl is proposed.
关键词： photoelectro-Fenton,photoelectrocatalysis,fluorine-doped tin oxide,organotin pollutants,Dark PEC
更新于2025-09-23 15:21:01
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Magnetically separable nanocomposites based on ZnO and their applications in photocatalytic processes: A review
摘要： Among the most challenging problems that human beings appear to face are depleting energy sources and increasing environmental pollutions. Heterogeneous photocatalytic processes are the most rewarding technology to generate renewable energy and degrade environmental pollutants. In these processes, semiconductors are used as photocatalysts. ZnO is a widely used photocatalyst, because of its strong oxidation ability, cost effectiveness, non-toxicity, versatility in synthesis, abundance in nature, and ease of crystallization. However, pure ZnO has some drawbacks, due to its wide band gap, poor solar-light utilization, and rapid recombination of the photoinduced charge carriers. Modification of ZnO using different strategies including coupling with narrow band gap semiconductors, noble metal deposition, surface sensitization by organic dyes, and elemental doping can easily address these shortcomings. In addition, separation of photocatalysts from the treated systems limits their broad applications. Incorporation of photocatalysts in magnetic materials will help their recycling using external magnetic field. This combination leads to a new generation of photocatalysts, known as magnetically separable photocatalysts. The present review provides helpful insights into preparation of magnetically separable photocatalysts based on ZnO and their applications for degradations of different pollutants.
关键词： water pollutants,Magnetic photocatalysts,solar-energy conversion,ZnO-based nanocomposites
更新于2025-09-23 15:21:01
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Optimization and scale-up of an LED-illuminated microalgal photobioreactor for wastewater treatment
摘要： The use of LED-illuminated photobioreactors with microalgae has been extensively studied for wastewater treatment. Most studies have used isolated microalgae species; however, this practice does not match the reality of conditions in wastewater treatment plants. Operational conditions that promote greater growth of algal biomass and that remove pollutants most effectively are disputed in the literature. In this context, LED–illuminated photobioreactors with microalgae were evaluated using multivariate analysis in order to optimize removal of pollutants (nitrogen, phosphorus, and carbonaceous organic matter). Three variables were evaluated: operating time, LED wavelength, and luminous ?ux intensity. A microalgae consortium was used in the photobioreactor. In addition to the LED-illuminated photobioreactors, control photobioreactors illuminated by sunlight were also operated. Using the results obtained in the optimization, a scaled-up reactor approximately 8.5 times larger in volume was operated to evaluate if the behavior would be maintained. The best operational conditions for the removal of pollutants were observed in LED-illuminated photobioreactors operated under a light intensity of 700 μmol·m?2s?1 for 15 days. Under these conditions, it was possible to remove 89.97% of carbonaceous organic matter, 86.50% of nitrogen, and 30.64% of phosphorus. The scaled-up photobioreactor operated with similar performance.
关键词： multivariate optimization,Light-emitting diode,microalgae,scale-up,removal of pollutants
更新于2025-09-23 15:19:57
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A water-stable Eu <sup>III</sup> -based MOF as a dual-emission luminescent sensor for discriminative detection of nitroaromatic pollutants
摘要： A water-stable EuIII-based metal–organic framework (MOF) with dual-emission luminescence behavior, namely {[Eu4(INO)5(μ3-OH)2Cl4(H2O)]·(NO3)·(H2O)5}n (Eu-MOF; HINO = isonicotinic acid N-oxide), was successfully constructed by the solvothermal reaction of Eu3+ ions with the organic ligand HINO. The cationic 3D framework contains microporous channels with accessible Lewis-base sites and NO3? ions as balanced anions, which all contribute to the selective detection of multifarious analytes. This MOF shows ratiometric detection of acetone, Cr2O72? ions, and nitroaromatic compounds (NACs). In particular, it shows great recognition of four NACs in water, representing the first LnIII-MOF which can display distinguishing fluorescence phenomena on NACs rather than relying on the quenching effect. Furthermore, this is also the first example of a MOF-sensor for detecting these explosives discriminatively by ratiometric methods. Additionally, the mechanisms for luminescent responses towards different analytes have been discussed in detail.
关键词： luminescent sensor,dual-emission,ratiometric detection,EuIII-based MOF,nitroaromatic pollutants,water-stable
更新于2025-09-19 17:15:36
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Scaling-up a heterogeneous H2O2/TiO2/solar-radiation system using the Damk?hler number
摘要： A falling film photocatalytic solar reactor (FFR) and a tubular reactor with compound parabolic collectors (CPCR) were modeled. An empirical reaction mechanism was proposed for the heterogeneous photocatalytic degradation of organic contaminants using TiO2, and H2O2. An analytical kinetic rate was deducted from the mechanism in order to describe the change of H2O2 concentration and the rate of destruction of total organic carbon (TOC). The profiles of the absorption rate of photons in the heterogeneous medium were estimated by using the absorption-scattering radiation six-flux model (SFM). A dimensionless number that we named Damk?hler of a photocatalytic reactor was proposed. Finally, the modeling was validated against experimental data for the TOC destruction obtained from the mineralization of dicloxacillin (DCX) and 4-chlorophenol (4-CP), which we considered as model pollutants.
关键词： Photoreaction scaling-up,Photoreactor design,Emerging pollutants,Titanium dioxide
更新于2025-09-19 17:15:36