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Organic components in atmospheric fine particulate matter have attracted much attention and several scientific studies have been performed, although most of the sample extraction methods are time consuming and laborious. Accelerated solvent extraction (ASE) is a new sample extraction method offering number of advantages, such as low extraction cost, reduced solvent and time consumption, and simplified extraction protocols. In order to optimize ASE methods to determine the concentrations of organic compounds in atmospheric fine particulate matter, different parameters were set out for the experiment, and the optimal method was selected according to the recoveries of the standard (i.e., n−alkanes and polycyclic aromatic hydrocarbons (PAHs)). This study also involves a comparison of the optimal method with the traditional method of ultrasonic extraction (USE). In addition, the optimized method was applied to measure the mass concentrations of organic compounds (n−alkanes and PAHs) in fine particulate matter samples collected in Beijing. The findings showed that the average recovery of target compounds using ASE was 96%, with the majority of compounds falling within the confidence levels, and the ASE recoveries and precision were consistent with the USE method tested. Furthermore, ASE combines the advantages of high extraction efficiency, automation, and reduced solvent use. In conclusion, the optimal ASE methods can be used to extract organic components in atmospheric particulate matter and serve as a point of reference for the development of analytical methodologies for assessing organic compounds in atmospheric particulate matter in China. [ABSTRACT FROM AUTHOR]

In this research, high strength ceramsite was sintered by zinc contaminated soil and red mud. In addition, the influence of sintering temperature and red mud addition on ceramsite properties and Zn immobilization were investigated, and the Zn immobilization mechanisms were determined. The X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM-EDS), and BCR sequential extraction technique were used to determine the crystal phases, microstructures, and Zn immobilization. Under the optimum synthesis conditions (sintering temperature of 1150 °C and the red mud addition of 5%), the sintered ceramsite exhibited a Zn loss rate of 10.31%, Zn leaching concentration of 0.13 mg/L (performed by rotating vibration device), bulk density of 1052.6 kg/m3, 1 h water absorption of 1.06%, and cylindrical compressive strength of 27.06 MPa, implying that the ceramsite obtained under this conditions not only meets the Chinese National Standards and has no environmental risk. High temperature and the addition of red mud were beneficial to the immobilization of Zn in ceramsite. The main immobilization mechanism of Zn in ceramsite was the formation of ZnFe x Al 2−x O 4 spinel and the encapsulation of glass phase. Thus, Zn can be immobilized effectively by ceramsite prepared from zinc contaminated soil and red mud at high temperature. [ABSTRACT FROM AUTHOR]