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Recently, emerging nanoadsorbents, such as graphene/(reduced) graphene oxide (GO)-based nanomaterials, have been prepared and used in different environmental applications, particularly water purification. This study is a review of the research progress on adsorption mechanisms for bisphenol A removal, which is significantly influenced by the physicochemical properties of various graphene/(reduced) GO-based nanomaterials and water quality conditions. In addition, this study presents the beneficial knowledge for the application of these nanomaterials for water purification. Results on the removal of bisphenol A and several other comparable contaminants using various graphene/(reduced) GO-based nanoadsorbents suggest that their removal can vary significantly depending on the properties of compounds or adsorbents and water chemistry conditions. Therefore, the bisphenol A adsorption performance of these nanomaterials is discussed: (i) to evaluate the overall adsorption capacities of various graphene/(reduced) GO-based nanomaterials based on the properties of nanomaterials and comparable contaminants; (ii) to summarize the influences of main water quality factors, such as pH, temperature, background ions/alkalinity, and natural organic matter or other organics, on adsorption; (iii) to discuss the key mechanisms that affect adsorption on these nanomaterials; and (iv) to describe the possible desorption and reusability of these carbon-based nanomaterials. [ABSTRACT FROM AUTHOR]

Conventional liquid–liquid extraction coupled with gas chromatography/mass spectrometry (GC/MS) was improved for the determination of twelve synthetic musk compounds (SMs) in water samples by consideration of pH and organic solvents for extraction. Samples collected from eleven different points of the Han River estuary and a coastal area were analysed, and the overall concentration of SMs downstream of the Han River was higher than of the coastal area. The extraction efficiencies were above 74% for the twelve SMs from three different classes when using the optimum pH and extraction with dichloromethane (DCM). Results for method detection limit (MDL), method quantification limit (MQL)and recovery obtained by the established analytical method showed that it is adequate for the determination of SMs in real samples. Among the SMs, Galaxolide (HHCB) and Iso E Super (OTNE) had the highest concentrations and detection frequencies. By using the established analytical method, our study showed regional and seasonal distribution of SMs originated from the Han River in estuary and coastal areas. [ABSTRACT FROM AUTHOR]

Application of a drone-based, high-volume (38 L min−1) sampling system developed for time-resolved monitoring of elemental and organic carbon (EC and OC) is demonstrated in this study. Filter samples collected by the samplers were analyzed by a laboratory-based, thermal-optical transmittance (TOT) method of the National Institute for Occupational Safety and Health using a Sunset Laboratory OC-EC analyzer. The EC, OC, and total carbon (TC) results for filter samples collected by the high-volume (38 L min−1) sampler are compared to those obtained by a low-volume (4 L min−1) sampler at ground level. Prior to the use of the developed high-volume sampler at 150 m, three 30-min air samples, taken from 11:00 to 15:00, and three 1-h samples, taken between 15:00 and 22:00, were collected at ground level by the drone-based system. For reference, the low-volume filter sample was collected over the 12-h period on the same day. In addition, particulate matter and black carbon concentrations were obtained as supportive data. In the ground-level test, the average EC, OC, and TC concentrations determined with the high-volume (drone) samples agree well with those determined with the 12-h, integrated, low-volume sample. Further field samplings on the ground and at 150-m were conducted over 2 days to assess the developed drone-based sampling system for measurement of carbonaceous aerosols. The EC, OC, and TC concentrations at a 150-m altitude were successfully examined via drone-based, high-volume sampling and TOT analysis. Copyright © 2023 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

Based on the filter-sampled chemical composition data the seasonal variation of the optical properties of polydispersed aerosols, extinction, scattering, and absorption coefficient, are estimated for various types of aerosol mixtures. The mixtures considered in this study are the internal mixture, elemental carbon (EC)/ non-EC external mixture, and fully external mixture. This study also evaluated the sensitivity of the aerosol optical properties for different size distributions. The results show that the extinction coefficient can be mostly accounted for scattering and generally shows a good agreement with each mixture type in this case study. However, the absorption coefficient shows a different tendency for internal and external mixtures. This study also shows that the aerosol optical properties vary as a function of particle diameter at the same composition and mass concentration. This means that mass extinction, scattering, and absorption efficiencies, which were considered as constants in general, should be reassessed and more specifically described as a function of particle size. [ABSTRACT FROM AUTHOR]

The physical and chemical properties as well as the oxidative potential (OP) of water soluble components of coal combustion fine particles were examined. A laboratory-scale pulverized-coal burning system was used to produce coal combustion particles at different burning temperatures of 550 °C, 700 °C, 900 °C, and 1,100 °C. Few studies have reported the effects of burning temperature on both the chemistry and toxicity of coal combustion particles. The highest mass emission factor of particulate matter less than 2.5 µm (PM2.5) was found to be produced at 700 °C (3.51 g/kg), owing to strong elemental carbon (EC) emission and ash formation (ions and elements) resulting from the incomplete combustion of tar and char, and mineral fragmentation. The highest organic carbon in PM2.5 was found at 550 °C. At a temperature higher than 700 °C, the fraction of carbonaceous species decreased while the fractions of ions and elements increased owing to ash formation. Sulfate was found to be the dominant ionic species, followed by sodium, calcium, and magnesium. The highest emission of elements (Al, As, Ba, Cd, Co, Cu, Fe, Mn, Ni, Pb, Sr, Ti, V, and Zn) and the highest fractions of Fe and Al were observed at 700 °C. Intrinsic OP activities obtained from dithiothreitol (DTT) and electron spin resonance (ESR) assays showed the highest values at 550 °C, suggesting that fine particles from low-temperature coal combustion had the highest reactive oxygen species generation capability (potentially toxic) among various tested burning temperatures. The results of principal component analysis suggested a correlation between OP-DTT activity and OC, EC, Cd, Co, V, and Zn, while OP-ESR activity was associated with chloride, nitrate, Ba, Pb, Sr, and Ti. © 2018 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]