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The research of microplastics should start with quantitative analysis methods. At present, the commonly used dyeing methods for microplastics have the disadvantages of low fluorescence intensity and uneven dyeing distribution. Polystyrene microplastics (PS) were dyed by rotary evaporation and Nile Red (NR) dyes in this paper. Scanning electron microscope (SEM) and infrared spectroscopy (FTIR) were used to compare the changes of the microstructure and surface groups of PS before and after staining. The quantity of fluorescent PS (FPS) was counted by flow cytometry and compared with the results measured by fluorescence method. The results show that the dyeing eccifency of rotary evaporation on PS is in line with expectations, the relative standard deviation of quantitative analysis of small size FPS is less than 10%, and the fluorescence signal of FPS is strong and easy to detect. In the stability test of FPS, it is found that the dyeing effect of this method is stable, and it is suitable for dyeing PS of different sizes and samples in simulated environment.the dyeing efficiency is stable, and this method is suitable for dyeing PS of different sized and samples in simulated environment. [ABSTRACT FROM AUTHOR]

BiOBr nanoplates, marked as α-BiOBr and β-BiOBr, were synthesized via hydrothermal method using cetylpyridinium bromide (CPB) and NaBr as reactants, respectively. X-Ray Diffraction (XRD), transmission electron microscope (TEM), N2 adsorption/desorption, UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), and cyclic voltammetry (CV) were employed to characterize the obtained BiOBr. The results showed that α-BiOBr and β-BiOBr can absorb visible light and both the band gaps of them were about 2.76 eV. Under visible light irradiation, the photodegradation of organic dye sulforhodamine (SRB) and salicylic acid (SA) using α-BiOBr and β-BiOBr as the catalysts was carried out. The reaction kinetic constants of the degradation of SRB by α-BiOBr and β-BiOBr were 0.00602 min-1 and 0.0047 min-1, respectively, which indicated that the photocatalytic activity of α-BiOBr was higher than that of β-BiOBr. The UV-Vis DRS and total organic carbon (TOC) were also monitored, and the TOC removal rate of α-BiOBr and β-BiOBr was 86% and 48%, respectively. At the same time, hydrogen peroxide (H2O2) and active radicals were measured and analyzed, which showed that the main active species was oOH during the photocatalytic reaction. [ABSTRACT FROM AUTHOR]

As an emerging environmental pollutant, microplastics have attracted much attention, but the sources and health hazards of atmospheric microplastics (AMPs) remain unclear. In order to explore the distribution characteristics, assess the risk of human respiratory exposure, and analyze the sources of AMPs in different functional areas of Yichang City, AMPs samples from 16 observation points were collected and analyzed, and the HYSPLIT model was used. The results showed that the main shapes of AMPs in Yichang City were fiber, fragment, and film, and six colors were observed including transparent, red, black, green, yellow, and purple. The smallest size was 10.42 μm, and the largest was 4761.42 μm. The deposition flux of AMPs was (4400±474) n·(m 2 ·d) -1 . The types of APMs were polyester fiber (PET), acrylonitrile-butadiene-styrene copolymer (ABS), polyamide (PA), rubber (Rubber), polyethylene (PE), cellulose acetate (CA), and polyacrylonitrile (PAN). The order of the subsidence flux in each functional area was as follows:urban residential area>agricultural production area>landfill>chemical industrial park>town residential area. The human respiratory exposure risk assessment models showed that the daily intake of AMPs (EDI) for adults and children in urban residential areas was higher than in town residential areas. The atmospheric backward trajectory simulation showed that the AMPs in the districts and counties of Yichang City mainly came from the surrounding areas via short-distance transportation. This study provided basic data support for the research on AMPs in the middle reaches of the Yangtze River and was of great significance for the traceability and health risk research of AMPs pollution.

As a visible light photocatalyst, bismuth oxide bromide (BiOBr) was used to catalyze the degradation of beta-cypermethrin (beta-CP). The photocatalytic degradation of beta-CP was studied with gas chromatography. The effects of pH and catalyst dose on the photocatalytic degradation efficiency were discussed. The oxidization and mineralization of beta-CP were detected by chemical oxygen demand (COD) analyzer. The results showed that beta-CP could be effectively degraded under visible light irradiation using BiOBr as the catalyst. At given experimental conditions, the degradation rate of beta-CP reached 94. 68% after 10 h and the COD removal rate reached 67. 99% after 36 h. With the increase of catalyst dose and pH value, the degradation rate was improved. The photocatalytic oxidation species was determined by peroxidase method and terephthalic acid fluorescence method. These results suggested that the photocatalytic degradation process mainly referred to hydroxyl radical ( OH) mechanism.