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Multifunctional and Recyclable TiO2 Hybrid Sponges for Efficient Sorption, Detection, and Photocatalytic Decomposition of Organic Pollutants
摘要： Developing techniques for monitoring and removing organic pollutants such as solvents and dyes in environmental media is a very important task nowadays. To get rid of the pollutants, efficient materials that can sorb, detect, and decompose such compounds have been consistently sought after. Herein, we demonstrate a simple and inexpensive method to fabricate eco-friendly multifunctional and recyclable TiO2 hybrid sponges composed of a polydimethylsiloxane (PDMS) network and functional nanoparticles. Water-soluble crystals were used to construct porous templates and TiO2 nanoparticles were additionally integrated into the templates where liquid PDMS was filled. After curing the PDMS, the TiO2 integrated hybrid sponges were finally obtained by dissolving the templates with water. By using the fabricated hybrid sponges, sorbed organic pollutants were qualitatively detected via molecular-specific Raman signals. Furthermore, we showed the recyclability by achieving photocatalytic decomposition of the sorbed pollutants induced by the TiO2 nanoparticles. These results are instructive for further applications and also contribute toward solving problems relating to environmental pollution.
关键词： TiO2 hybrid sponge,Raman detection,photocatalytic decomposition,organic pollutants,efficient sorption
更新于2025-11-25 10:30:42
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Mesoporous TiO2-BiOBr Microspheres with Tailorable Adsorption Capacities for Photodegradation of Organic Water Pollutants: Probing Adsorption-Photocatalysis Synergy by Combining Experiments and Kinetic Modeling
摘要： Understanding adsorption-photocatalysis synergy helps advance solar-driven photodegradation of organic wastewater pollutants. To evaluate the synergy, mesoporous TiO2(amorphous)-BiOBr microspheres were facilely synthesized as model photocatalysts and characterized by XRD, SEM, TEM/HRTEM, XPS, nitrogen adsorption-desorption, UV-vis DRS, photoluminescence, and FTIR. The characterizations and photodegradation tests suggested that the composites had both adsorption sites and photocatalysis sites on BiOBr phase, while homogeneously distributed TiO2 in BiOBr microplates tailored the size of BiOBr crystallites. Accordingly, surface areas of the composites spanned from 22 to 155 m2/g and adsorption capacities for methyl orange (MO) ranged from 16 to 54 mg/g, controlled by the TiO2 content. In addition to experiments, kinetic modeling that combined adsorption with photocatalysis was developed and aided elucidating the synergy and quantitatively evaluating the composites with extracted rate constants from experimental data. The rate constant of the composite (Ti/Bi = 0.6) was calculated to be 3 times that of the pure BiOBr. Though adsorption promoted MO photodegradation, the capacity of the composite for MO adsorption and photodegradation decreased dramatically during the cycling tests. Nevertheless, this problem did not happen during photodegradation of rhodamine B and phenol on the composite and photodegradation of MO on pure BiOBr. This was explained by possible accumulation of degradation intermediates on the composite surface. This study provides a useful approach to investigate the adsorption-photocatalysis synergy from the perspectives of experiments and kinetic modeling and implies the necessity of scrutinizing the adverse effects of high levels of adsorption on recyclability of the photocatalysts.
关键词： Organic pollutants photodegradation,Kinetic modeling,TiO2-BiOBr microspheres,Tailorable adsorption capacities,Adsorption-photocatalysis synergy
更新于2025-11-14 17:03:37
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Plasmonic MoO2 nanospheres assembled on graphene oxide for highly sensitive SERS detection of organic pollutants
摘要： The molybdenum oxide and graphene oxide (MoO2/GO) nanocomposite has been fabricated via simple hydrothermal assisted synthesis using Mo and MoO3 as precursors. The MoO2 nanospheres with porous hollow structure are assembled onto GO nanosheets. Profiting from the plasmonic effects of MoO2 and synergistic effect of MoO2 and GO, this hybrid nanomaterial exhibits significantly enhanced surface enhanced Raman scattering (SERS) activity for organic pollutants. The detection limit for rhodamine 6G (R6G) is 1.0 × 10?9 M, and the maximum enhancement factor (EF) reaches up to 1.05 × 107, which is the best among the semiconductor-based SERS materials. For practical application, the MoO2/GO SERS substrates are also applied to detect Methylene blue (MB) in river water, and the detection limit (1.0 × 10?8 M) can be acquired. Pyrene is also chosen as probe molecule, and quantitative determination is achieved with detection limit of 1.0 × 10?7 M. These demonstrate the well feasibility for multi-molecule detection. Furthermore, the nanocomposite displays high stability, reproducible stability, and acid and alkali resistance.
关键词： Organic pollutants,Plasmonic effect,SERS,Graphene oxide,Detection,MoO2
更新于2025-11-14 15:27:09
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The role of the reactive oxygen species and the influence of KBiO3 synthesis method in the photodegradation of methylene blue and ciprofloxacin
摘要： KBiO3 was synthesized by three methods: chemical substitution, hydrothermal and sonochemical. All reaction products were analyzed by X-ray powder diffraction and reveal that KBiO3 presents a cubic structure. The morphology of each sample was analyzed with scanning electron microscopy (SEM), and the micrographs show particles with cube-like (chemical substitution), spheres-like (sonochemical) and flakes-like (hydrothermal) shape. HR-TEM technique was used to confirm the crystal structure and to determine the particle size of the samples, also it was used to corroborate the morphology. The photocatalytic activity of KBiO3 was evaluated on the reactions of the degradation of methylene blue (MB) and Ciprofloxacin (CPFX). An almost 100% discoloration of MB was reached at 120 min with KBiO3 obtained by the sonochemical method and a 67% degradation of CPFX was obtained by KBiO3 synthesized by the hydrothermal method. These results were associated with the catalyst morphology and organic adsorption on the surface of the catalyst. With the aim for a further understanding of the photocatalytic degradation of MB and CPFX, scavengers such as benzoquinone, isopropanol, and catalase were added to the photocatalytic reaction in order to identify the reactive oxygen species (ROS) involved. It has been found that hydrogen peroxide (H2O2) was the primary oxidizing species for the degradation of MB; meanwhile in the case of the oxidation of CPFX occurred by the presence of the superoxide radical (O2?·).
关键词： Photocatalysis,Organic pollutants,Reactive oxygen species,Scavengers,KBiO3
更新于2025-09-23 15:23:52
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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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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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Robot path planning with two-axis positioner for non-ideal sphere-pipe joint welding based on laser scanning
摘要： The conversion and degradation of organic pollutants remain challenges relating to environmental science. Herein, we report the carbonization of organic pollutants (4-nitrophenol, 4-NP) toward metal-free nitrogen-doped graphene quantum dots (N-GQDs) using a one-pot solvothermal route. The resultant N-GQDs demonstrate excellent activity for the catalytic conversion of 4-NP to 4-aminophenol (4-AP) when exposed to near infrared (NIR) light because of their excellent upconverted photoluminescence and photothermal conversion ability. The NIR-enhanced reduction efficiency of 4-NP to 4-AP not only originates from the enhanced collisions between N-GQDs and 4-NP due to photothermal-increased Brownian movement of molecules, but also comes from the accelerated transfer rate of electrons produced by the photoexcitation of N-GQDs under NIR irradiation. The N-GQDs display excellent photostability and remain high activity even after five cycles of reuse. Such conversion of organic pollutants to highly efficient metal-free carbocatalysts has significant importance in relevance of the industrial production of aniline and paracetamol.
关键词： organic pollutants,metal-free photocatalysts,4-nitrophenol reduction,nitrogen-doped graphene quantum dots,NIR-enhanced catalytic activity
更新于2025-09-19 17:13:59
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A novel carbon quantum dots (CQDs) modified Cs <sub/>4</sub> PW <sub/>11</sub> O <sub/>39</sub> Fe(III)(H <sub/>2</sub> O) material to achieve high photocatalytic property
摘要： Keggin-type polyoxometalates is a kind of promising photocatalyst with adjustable light absorption range. However, the high recombination rate of photogenerated charge carriers hampered its photocatalytic efficiency. To solve this weakness, novel carbon quantum dots (CQDs) modified Cs4PW11O39Fe(Ⅲ)(H2O) photocatalysts (CQDs/Cs4PW11Fe) have been synthesized via a hydrothermal process. Phase structure, morphology, optical and electronic properties of the as prepared photocatalysts were systematically characterized by XRD, SEM, TEM, DRS and surface photovoltage tests. It could be found that CQDs was well deposited on the surface of Cs4PW11Fe, which has broadened the light absorption of Cs4PW11Fe. The photodegradation efficiencies of the CQDs/Cs4PW11Fe composite photocatalysts for RhB under visible light irradiation were clearly enhanced. Trapping experiments were carried out to detect the photocatalytic mechanisms. The charge transfer and separation efficiencies of the samples were confirmed by electrochemical impedance spectroscopy tests.
关键词： Carbon quantum dots,Organic pollutants,Photocatalysis,Solar energy utilization,Cs4PW11O39Fe(Ⅲ)(H2O)
更新于2025-09-19 17:13:59
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[American Society of Agricultural and Biological Engineers 2019 Boston, Massachusetts July 7- July 10, 2019 - ()] 2019 Boston, Massachusetts July 7- July 10, 2019 - <i>Calibrating UAV-Based Thermal Remote-Sensing Images of Crops with Temperature Controlled References</i>
摘要： Animal studies have indicated that persistent organic pollutants (POPs) affect thyroid hormone homeostasis, while epidemiological studies involving human have not shown consistent results. In this study, we investigated the associations between POP exposure and thyroid function among adult population of East China. One hundred eighty-six participants diagnosed with thyroid disease and 186 participants without thyroid disease from Shandong, China were enrolled in the case-control study during 2016 to 2017. We found that POP exposure was significantly and positively associated with the risk of thyroid disease. The association of thyroid disease with a sum of 17 POPs followed a nonmonotonic dose response, with an adjusted odds ratio of 2.09 (95% confidence intervals: 1.13?3.87, p = 0.019) for the second quartile. Among 186 participants in the control group, concentrations of POPs showed negative associations with triiodothyronine (T3), free T3 (FT3), thyroxine (T4), and free T4 (FT4) in males and positive associations with T4 and FT4 in females. Taken together, these findings suggest that POP exposure can disrupt thyroid hormone homeostasis and increase the risk of thyroid disease.
关键词： case-control study,East China,thyroid function,persistent organic pollutants,thyroid disease
更新于2025-09-19 17:13:59
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Wurtzite CoO: a direct band gap oxide suitable for a photovoltaic absorber
摘要： Rational design of high-efficiency carbon-based nanomaterials towards heterogeneous activation of peroxymonosulfate (PMS) for environmental remediation is highly desirable. Codoping of Co and N into carbon may synergistically modify the electronic structure of carbon and enhance its catalytic activity towards PMS. However, the synergistic mechanism between Co and N, especially the role of Co, remains unknown. Herein, Co and N codoped porous carbons (Co–N-PCs) were constructed for enhanced PMS activation. The Co doping level was varied to study the role of Co in Co–N-PCs. Results showed that codoping of Co and N into carbon generated a synergistic effect to enhance PMS activation for the degradation of organic pollutants. The kinetic constant of phenol degradation of the Co–N-PC was 48.4, or 17.6 times larger than that of porous carbon with only N or Co doping, and was superior to that of homogeneous Co2+ (best reported PMS catalyst). Moreover, the catalytic activity of Co–N-PC was significantly enhanced with the increase of Co–N coordination sites (Co–Nx), which could also inhibit Co leaching due to its strong binding. The experimental and DFT results revealed that the synergism of Co and N was ascribed to the combination of their different roles: the N doping mainly produced the charged carbon sites for PMS adsorption, while the Co doping mainly facilitated the electron transfer from carbon to PMS for its dissociation into sulfate radical.
关键词： Co and N codoped porous carbons,peroxymonosulfate,organic pollutants,heterogeneous activation,synergistic mechanism
更新于2025-09-11 14:15:04