This paper presents a method for microplastic (MP) mass quantification using a Focal Plane Array-based Fourier Transform Infrared imaging technique. It discusses the issue that particle number is not ...a conserved base quantity and hence less suited than mass to compare independent studies on MP in the environment. It concludes that MP mass should be included when quantifying MP pollution in the environment, supplementing the conventional approach of reporting particle numbers. Applying mass as the unit of MP measurement, the paper presents data showing that Danish wastewater treatment plants discharge around 3 t/year of MP in the size range 10–500 μm. This value corresponds to an annual per capita emission from these plants of 0.56 g MP/(capita year). The distribution of polymer types by mass and particle number differed because the size of MP particles of the different material types varied.
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•98% of MPs are removed from influent wastewater in WWTPs.•The annual MP discharge from WWTPs in Denmark is approx. 0.56 g/(capita year).•MPs are quantified by mass in addition to particle number.•Mass can be estimated using FT-IR imaging.
This study investigated the effect of alkali activation process conditions on the IR spectra, on which amount and types of zeolites in the resultant geopolymers influence significantly. Kaolinite was ...used as starting materials. The kaolinitic clay was first calcined to transform into the amorphous aluminosilicate phases (metakaolinite) and then activated with sodium silicate (as water glass) and sodium hydroxide. The effects of reaction systems composition (expressed as SiO2/Al2O3 and Al2O3/Na2O molar ratios) as well as synthesis temperature on the phase composition of obtained products have been determined. In particular, the structures of materials were examined using FT-IR spectroscopy in the middle infrared range. The results were compared to the XRD measurements, as well as SEM observations.
Alkali-activation treatment of the metakaolin yielded bulk materials with different amounts and types of zeolite, which reveal the IR spectra of received materials. With proper selection of the initial conditions (temperature and composition), it is possible to obtain a solid material containing zeolite phase such as zeolite X, zeolite A or sodalite. The presence of zeolite phase was confirmed by the measurement of spectra in the middle infrared. In particular in pseudolattice range of the spectra, i.e. 800–400 cm−1, there are bands associated with the ring vibrations, which are characteristic for secondary building units (SBU) occurred in zeolite structure. IR spectroscopy is also useful in the studies of resulting amorphous phase structure.
•The study investigated the effect of alkali activation conditions on the IR spectra.•Treatment of metakaoline with the use water glass and NaOH was carried out.•It is possible to obtain a sodium zeolites in geopolimeric matrix.•We used the infrared spectra to describe the geopolymerization progress.
Breast cancer is regarded as the most malignant tumor among women throughout the world. Therefore, early detection and proper diagnostic methods have been known to help save women's lives. Fourier ...Transform Infrared (FT-IR) spectroscopy, coupled with PCA-LDA analysis, is a new technique to investigate the characteristics of serum in breast cancer. In this study, 43 breast cancer and 43 healthy serum samples were collected, and the FT-IR spectra were recorded for each one. Then, PCA analysis and linear discriminant analysis (LDA) were used to analyze the spectral data. The results showed that there were differences between the spectra of the two groups. Discriminating wavenumbers were associated with several spectral differences over the 950‐1200cm‐1(sugar), 1190‐1350cm‐1 (collagen), 1475‐1710cm‐1 (protein), 1710‐1760cm‐1 (ester), 2800‐3000cm‐1 (stretching motions of –CH2 & ‐CH3), and 3090‐3700cm‐1 (NH stretching) regions. PCA-LDA performance on serum IR could recognize changes between the control and the breast cancer cases. The diagnostic accuracy, sensitivity, and specificity of PCA-LDA analysis for 3000‐3600cm‐1 (NH stretching) were found to be 83%, 84%, 74% for the control and 80%, 76%, 72% for the breast cancer cases, respectively. The results showed that the major spectral differences between the two groups were related to the differences in protein conformation in serum samples. It can be concluded that FT-IR spectroscopy, together with multivariate data analysis, is able to discriminate between breast cancer and healthy serum samples.
The averaged FT-IR spectra of control and patients in the range of 4000‐400cm‐1. Display omitted
•FT-IR spectroscopy, coupled with PCA-LDA analysis, is a new technique to investigate the characteristics of serum in breast cancer.•The main differences between FT-IR spectra of controls and breast cancer patients in the spectra are due to protein modifications.•Accuracy and sensitivity, of PCA-LDA for 3000‐3600cm‐1 were for control (83%, 84% 74%) and for patients (80%, 76% 72%), respectively.
The global presence of microplastic (MP) in aquatic ecosystems has been shown by various studies. However, neither MP concentrations nor their sources or sinks are completely known. Waste water ...treatment plants (WWTPs) are considered as significant point sources discharging MP to the environment.
This study investigated MP in the effluents of 12 WWTPs in Lower Saxony, Germany. Samples were purified by a plastic-preserving enzymatic-oxidative procedure and subsequent density separation using a zinc chloride solution. For analysis, attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FT-IR) and focal plane array (FPA)-based transmission micro-FT-IR imaging were applied. This allowed the identification of polymers of all MP down to a size of 20 μm. In all effluents MP was found with quantities ranging from 0 to 5 × 101 m−3 MP > 500 μm and 1 × 101 to 9 × 103 m−3 MP < 500 μm. By far, polyethylene was the most frequent polymer type in both size classes. Quantities of synthetic fibres ranged from 9 × 101 to 1 × 103 m−3 and were predominantly made of polyester. Considering the annual effluxes of tested WWTPs, total discharges of 9 × 107 to 4 × 109 MP particles and fibres per WWTP could be expected. Interestingly, one tertiary WWTP had an additionally installed post-filtration that reduced the total MP discharge by 97%. Furthermore, the sewage sludge of six WWTPs was examined and the existence of MP, predominantly polyethylene, revealed. Our findings suggest that WWTPs could be a sink but also a source of MP and thus can be considered to play an important role for environmental MP pollution.
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•Microplastic (MP) was analysed in effluents from 4 tertiary and 8 secondary WWTPs.•Micro-FT-IR imaging allowed polymer identification of all MP down to a size of 20 μm.•MP was determined in all effluents of examined WWTPs.•An installed post-filtration (tertiary treatment) removed 97% of MP.•WWTP may act as MP source but also as sink since MP was detected in sewage sludge.
Simulating photosynthesis has long been one of the ideas for realizing the conversion of solar energy into industrial chemicals. Heterogeneous N2 photofixation in water is a promising way for ...sustainable production of ammonia. However, a mechanistic understanding of the complex aqueous photocatalytic N2 reduction is still lacking. In this study, a light‐dependent surface hydrogenation mechanism and light‐independent protection of catalyst surface for N2 reduction are revealed on ultrathin Bi4O5Br2 (BOB) nanosheets, in which the creation and annihilation of surface bromine vacancies can be controlled via a surface bromine cycle. Our rapid scan in situ FT‐IR spectra verify that photocatalytic N2 reduction proceeds through an associative alternating mechanism on BOB surface with bromine vacancies (BrV‐BOB). This work provides a new strategy to combine light‐dependent facilitated reaction with light‐independent regeneration of catalyst for advancing sustainable ammonia production.
Photocatalytic N2 reduction on ultrathin Bi4O5Br2 nanosheets reveals a light‐dependent surface hydrogenation mechanism and light‐independent protection of the catalyst surface. Creation and annihilation of surface bromine vacancies can be controlled via a surface bromine cycle.
The correlation between water molecules and polylactide was clarified. The crystallinity in stereocomplex (SC) crystal spherulites was investigated using microbeam wide-angle X-ray diffraction. The ...crystallinity was higher in the central region, and edge-on lamellae grew in a twisted manner. The hydrogen bonding in SC-crystal spherulites was evaluated via microbeam FT-IR spectroscopy in a humidity-controlled cell. The water-derived bands corresponding to OH vibration and HOH bending increased with increasing humidity. Microbeam FT-IR spectroscopy was used to evaluate the water absorption behavior of crystalline films depending on their position. Coarse-grained molecular dynamics simulations indicated that the number of adsorbed water molecules increased with decreasing crystallinity. In SC-crystal spherulites, water molecules are absorbed in both amorphous and crystalline regions but with greater difficulty in the crystalline regions. These insights into water molecule absorption on SC-crystal spherulite can facilitate the development of polylactide materials with controlled biodegradability for advanced medical and optical applications.
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•Water absorption on PLLA/PDLA blended films was investigated.•Interactions between water molecules and Sc-crystal spherulites were clarified.•The crystallinity of the spherulites was investigated using microbeam XRD.•Hydrogen bonding in spherulites was assessed by microbeam FT-IR spectroscopy.
Microplastic (MP) appears to be omnipresent in the atmosphere, raising concerns about dispersion across environmental compartments, ecological consequences and human health risks by inhalation. To ...date, data on the sources of atmospheric MP and deposition to river catchment areas are still sparse. We, therefore, took aerosol and total atmospheric deposition samples in the catchment area of the large German river Weser to estimate microplastic deposition fluxes (DFs) at six specific sites and airborne MP concentrations. Sampling in rural, suburban, and urban environments and wastewater treatment plants (WWTPs) was performed, aiming at a variation in airborne MP pollution and elucidating potential MP source areas. Aerosol samples were taken twice in April and October while monthly total deposition samples were collected over a period from March to October. Microplastics were detected in all analysed aerosol samples by Raman spectroscopy down to 4 μm, and in all 32 total deposition samples by μFT-IR down to 11 μm. Average MP number concentrations of 91 ± 47 m−3 were found in aerosol samples. The measured total MP number DFs ranged between 10 and 367 N m−2 day−1 (99 ± 85 mean ± SD) corresponding to total deposition of 0.05 ± 0.1 kg ha−1 per year and to an estimated 232 metric tons of plastic being deposited in the Weser River catchment annually. MP number DFs were higher in urban than rural sites. An effect of WWTPs on the MP abundance in air was not observed. Polypropylene, polyethylene, polyethylene terephthalate, polyvinyl chloride, polystyrene, and silicone fragments were found as the predominant polymer types in total deposition samples, while polyethylene particles dominated in aerosol samples. The results suggest that proximity to sources, especially to cities, increase the numbers of MP found in the atmosphere. It further indicates that atmospheric MP considerably contributes to the contamination of both aquatic and terrestrial habitats.
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•Average airborne MP concentration of 91 ± 47 particles per m3 (>4 μm)•Average total MP deposition rate of 99 ± 85 particles per m2 per day (>11 μm)•Atmospheric deposition must be considered as a diffuse MP source.•Proximity to sources, especially to cities, increase MP numbers in the atmosphere.•PP and PE fragments predominate in air in Central and Northwest Germany.
In this work, the heavy metal borate glass system (B2O3-PbO) was doped with a hybrid of transition metal and rare earth ions via a fixed ratio of MnO2 and a variable La2O3 ratio. X-ray diffraction ...spectra confirmed the amorphous nature of the manufactured glassy system. The effect of La2O3 ions in causing modifications to the internal structure was examined through density measurements and Fourier-transform infrared spectroscopy. According to structural studies, the density increases gradually with increasing La2O3/B2O3 concentrations, in addition to an increase in the ratio of non-bridging oxygen resulting from structural transformations between the BO4 and BO3 units. The optical absorption bands were deconvoluted and studied, where the samples acquired a light brown color resulting from the absorption band at ∼466 nm and the electronic transition 6A1 g(S) → 4A1 g(G). The detected absorption bands verified the existence of Mn2+/Mn3+ in octahedral/tetrahedral sites. However, photoluminescence spectra indicated the tendency of Mn2+ ions to occupy more octahedral coordination. The shift of the fundamental absorption edges to lower energy with La2O3 addition confirmed the successive narrowing of the optical band gap. In addition, the entry of La3+ ions improved the optical basicity and electronic polarization, raising linear/nonlinear refractive indices. The ligand field effect showed the role of La3+ ions in reducing the crystal field intensity around Mn2+ ions and increasing the nephelauxetic ratio, indicating a gradual increase in the ionic bonding nature between the Mn2+ cations and the adjacent ions.
•The optical spectra of Mn2+/Mn3+ ions can be tuned in the visible region by La3+ additions.•The linear/nonlinear refractive indices increased by La2O3 addition.•Ligand field parameters showed an increase in the ionic nature of Mn2+ ions•The Mn2+ ions occupied tetrahedral and octahedral sites.
In the present work, Zinc Oxide (ZnO) nanoparticles (NPs) were synthesized by the chemical co-precipitation method using Zinc Chloride as the initial chemical, while Nickel and Cobalt chloride as ...dopants. Phase identification of metal (Ni, Co) doped Zinc Oxide nanoparticles (NPs) was observed using x-ray diffraction (XRD). The small lattice distortion or phase changes appeared due to shifting of diffraction angles peaks towards larger angle in ZnO are corresponded to metal (Ni, Co) dopant. The average crystallite size appears to decrement in NP size from 7.67 nm to 6.52 nm and 5.35 nm to 5.17 nm with increasing 5 % to 80 % of metal (Ni, Co) dopant respectively. The optical characteristics, including the absorption spectra of the prepared sample were observed through UV–Vis spectroscopy, Meanwhile SEM confirmed the observation of composition change in specimen with metal (Ni, Co) dopant concentration. The bandgap value was also found decrement 5.23 eV to 5.05 eV with increment of metal (Ni, Co) dopant concentration. The functional groups were measured by Fourier transformation infrared spectroscopy (FTIR). FTIR peaks found the metal (Ni, Co) doped ZnO with the vibration mode of (Zn2+ –O2−) ions due to the increment of dopant concentrations. Furthermore, electrical results show the ohmic behavior of prepared samples. These findings indicate the possibility of tuning optical, structural and electrical properties of metal (Ni, Co) doped ZnO with various dopant concentrations of Nickel and will have great potential to find application in optoelectronic devices.
Micro-plastic (MP) contamination of drinking water is an emerging global concern. Findings on the cytotoxic effects of MPs in human cells are an incentive to investigate the MP concentration in ...drinking water. The present study quantitatively and qualitatively analyzes the MPs in 10 brands of single-use PET-bottled water, sourced from Thailand. A set of glass-bottled water was similarly analyzed to compare the MP concentrations between the two packaging. Two sorting techniques were used: 1) fluorescent tagging with Nile Red (≥6.5 μm) and 2) optical microscopy (≥50 μm). ATR-FT-IR (≥50 μm) and confocal Raman spectroscopy (1–50 μm) were also used. The MP concentration was found to be 140 ± 19 p/L in single-use plastic-bottled water and 52 ± 4 p/L in glass-bottled water. Plastic bottles had a significantly higher MP quantity than the latter. Both 6.5–20 μm and 20–50 μm MPs showed significant dominance over the ≥50 μm fraction. Fibers accounted for 62.8% of the total particle content, followed by fragments. Under optical microscopy, ≥50 μm particles were 10 ± 1 p/L (on average), which did not differ largely from that of fluorescent-tagged particles in the same size range (12 ± 1 p/L), implying the suitability of both techniques to sort ≥50 μm MPs. However, fluorescent-tagging was more reliable for MP identification in drinking water, particularly in the 6.5–50 μm range. Among the particles that were confirmed to be polymeric, PET, PE, PP, and PA were dominant. Accordingly, the contamination mainly emanates from the packaging, but could also occur during the manufacturing process. Given the direct human exposure to MPs through bottled water and their cellular toxicity, further studies are encouraged on smaller-sized MPs in drinking water.
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•Single-use PET-bottled water contained an average of 140 ± 19 MPs per liter.•MPs of 6.5–20 μm range showed a significant dominance, and fibers were abundant.•Major polymers detected for ≥50 μm particles: PE, PET, PP, and PA.•Bottle packaging plays a significant role in the MP contamination.
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