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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]

Soils contaminated with polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofurans (PCDFs), and dioxin-like (dl) polychlorinated biphenyls (PCBs), known as persistent organic pollutants (POPs), have garnered global attention because of their toxicity and persistence in the environment. The standard method for target analytes has been used; however, it is an obstacle in large-scale sample analysis due to the comprehensive sample preparation and high-cost instrumental analysis. Thus, analytical development of inexpensive methods with lower barriers to determine PCDDs/Fs and dl-PCBs in soil is needed. In this study, a one-step cleanup method was developed and validated by combining a multilayer silica gel column and Florisil micro-column followed by gas chromatography with triple quadrupole mass spectrometry (GC-QqQ-MS/MS). To optimize the separation and quantification of 17 PCDDs/Fs and 12 dl-PCBs in soils, the sample cleanup and instrumental conditions were investigated. For quantification method validation, spiking experiments were conducted to determine the linearity of the calibration, recovery, and method detection limit of PCDDs/Fs and dl-PCBs using isotopic dilution GC-QqQ-MS/MS. The applicability of the simultaneous determination of PCDDs/Fs and dl-PCBs was confirmed by the recovery of native target congeners and labeled surrogate congeners spiked into the quality-control and actual soil samples. The results were in good agreement with the requirements imposed by standard methods. The findings in this work demonstrated the high accessibility of the sample cleanup and analysis methods for the efficient determination of PCDDs/Fs and dl-PCBs in contaminated soils. [ABSTRACT FROM AUTHOR]

The concentration of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere has been continually monitored since their toxicity became known, whereas nitro-PAHs (NPAHs) and oxy-PAHs (OPAHs), which are derivatives of PAHs by primary emissions or secondary formations in the atmosphere, have gained attention more recently. In this study, a method for the quantification of 18 NPAH and OPAH congeners in the atmosphere based on combined applications of gas chromatography coupled with chemical ionization mass spectrometry is presented. A high sensitivity and selectivity for the quantification of individual NPAH and OPAH congeners without sample preparations from the extract of aerosol samples were achieved using negative chemical ionization (NCI/MS) or positive chemical ionization tandem mass spectrometry (PCI-MS/MS). This analytical method was validated and applied to the aerosol samples collected from three regions in Northeast Asia—namely, Noto, Seoul, and Ulaanbaatar—from 15 December 2020 to 17 January 2021. The ranges of the method detection limits (MDLs) of the NPAHs and OPAHs for the analytical method were from 0.272 to 3.494 pg/m3 and 0.977 to 13.345 pg/m3, respectively. Among the three regions, Ulaanbaatar had the highest total mean concentration of NPAHs and OPAHs at 313.803 ± 176.349 ng/m3. The contribution of individual NPAHs and OPAHs in the total concentration differed according to the regional emission characteristics. As a result of the aerosol samples when the developed method was applied, the concentrations of NPAHs and OPAHs were quantified in the ranges of 0.016~3.659 ng/m3 and 0.002~201.704 ng/m3, respectively. It was concluded that the method could be utilized for the quantification of NPAHs and OPAHs over a wide concentration range. [ABSTRACT FROM AUTHOR]