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Determination of the microplastics emission in the effluent of a municipal waste water treatment plant using Raman microspectroscopy
摘要： Samples from the secondary clarifier effluent of a waste water treatment plant (serving 98500 inhabitants) were analyzed to determine the microplastics (MP) emission. The samples were collected using a stainless steel centrifugal pump and filtered through a 10 mm stainless steel cartridge filter. Microplastics particles (MPPs) and microplastics fibers (MPFs) were recovered by chemical and physical sample purification. To remove natural organic matter, the samples were first subjected to oxidative treatment with H2O2 and NaClO. Inorganic materials were subsequently removed by density separation in ZnCl2 (r = 1.9 g/cm3) using a centrifuge. Special centrifuge tubes were developed for this purpose. Sample analysis was performed on a Si filter by Raman micro-spectroscopy. Particles with a diameter (dp) ≥ 10 mm were analyzed. The results were differentiated by dry and wet weather samples. On average, 5900 MPPs m?3 were identified in the effluent on wet weather days compared to 3000 MPPs m?3 on dry weather days. Most of the MPPs detected were in the 30 mm < dp < 100 mm size range. The MPFs ranged between 100 mm and 1000 mm in length. While most of the MPFs were of PET origin, the MPPs consisted mainly of PET, PP, PE and PS.
关键词： Raman microspectroscopy,Oxidative treatment,Si filter,Centrifugation,Microplastics emission,WWTP effluent
更新于2025-09-23 15:22:29
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Laser beam scattering for the detection of flat, curved, smooth, and rough microplastics in water
摘要： Microplastic (MP) pollution is alarming and poses an imminent threat to the environment with a direct impact on our health and that of fauna in natural water bodies. The understanding of light–MP interactions in water as well as the need for low-cost and robust optical sensors for the detection of MPs that appear everywhere is, therefore, necessary. We have demonstrated the use of a prototype optical sensor in the detection of flat and curved [from polyethylene terephthalate (PET) water bottle] pristine and rough MPs from commercial PET and low-density polyethylene plastics in water. The optical sensor utilizes a photodiode and charge-coupled device (CCD) camera to record simultaneously the specular reflection and the speckle pattern modified by the MPs. In this study, we have exploited the specular reflection in the detection of the pristine samples, whereas the speckle contrast, the normalized standard deviation of the speckle pattern intensity, is utilized in the qualitative estimation of the “effective” surface roughness of the MPs. With the sensor, one can, therefore, detect PET MPs with varying average surface roughness, Ra an indication of MP aging, embedded in water. The prototype can detect the effect of size, type, curvature, transparency, and the translucency of sunken and/or floating MPs in water based on the reflection, scattering, and the (edge) diffraction of light. However, the optical sensor is limited in the discrimination of MP concentration in water. Further modifications to the sensor are needed for its practical implementation in complex natural water bodies and wastewaters.
关键词： Microplastics,Surface roughness,Laser speckle pattern,Specular reflection,Speckle contrast
更新于2025-09-23 15:19:57
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Compositional Control in 2D Perovskites with Alternating Cations in the Interlayer Space for Photovoltaics with Efficiency over 18%
摘要： Microplastics (MPs) are considered as a pollutant of marine environments and have become a global environmental problem in recent years. A number of studies have demonstrated that MPs can enter the human food chain, and MPs have even been detected in human stools. Therefore, there is increasing concern about the potential risks of MPs to human and animal health. Here, we investigated maternal polystyrene MPs exposure during gestation and lactation and evaluated the potential effects on dams and the F1 (both PND 42 and 280) and F2 (PND 42) generations. The results of transcriptome and 16S rRNA sequencing indicated that MPs caused the metabolic disorder in maternal MPs associated with gut microbiota dysbiosis and gut barrier dysfunction. Simultaneously, maternal MPs exposure also had the intergenerational effects and even caused long-term metabolic consequences in the F1 and F2 generations. In addition, in F1 (PND 42), the composition of gut microbiota did not change significantly, while the hepatic transcriptome and serum metabolite changes showed the potential risk in metabolic disorder. Then, the potential of hepatic lipid accumulation was observed in adult F1 mice (PND 280), especially in the female mice. Our results demonstrated that maternal MPs exposure during gestation and lactation increases the risk of metabolic disorder, and these results provide new insight into the potential long-term hazards of MPs.
关键词： Polystyrene,Intergenerational effects,Maternal exposure,Microplastics,Metabolic disorder,Gut microbiota
更新于2025-09-19 17:13:59
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Enhanced Visible Light Photodegradation of Microplastic Fragments with Plasmonic Platinum/Zinc Oxide Nanorod Photocatalysts
摘要： Microplastics are persistent anthropogenic pollutants which have become a global concern owing to their widespread existence and unfamiliar threats to the environment and living organisms. This study demonstrates the degradation of fragmented microplastics particularly low-density polyethylene (LDPE) film in water, through visible light-induced plasmonic photocatalysts comprising of platinum nanoparticles deposited on zinc oxide (ZnO) nanorods (ZnO-Pt). The ZnO-Pt nanocomposite photocatalysts were observed to have better degradation kinetics for a model organic dye (methylene blue) compared to bare ZnO nanorods, attributed to the plasmonic effects leading to better interfacial exciton separation and improved hydroxyl radical activity along with a 78% increase in visible light absorption. These demonstrations of the plasmonically enhanced photocatalyst enabled it to effectively degrade microplastic fragments as confirmed following the changes in carbonyl and vinyl indices in infrared absorption. In addition, visual proof of physical surface damage of the LDPE film establishes the efficacy of using plasmonically enhanced nanocomposite photocatalytic materials to tackle the microplastic menace using just sunlight for a clean and green approach towards mitigation of microplastics in the ecosystem.
关键词： microplastics,platinum nanoparticle,ZnO nanorod,LDPE film,visible light photodegradation,nanocomposite
更新于2025-09-16 10:30:52