No abstract

In this study, Xuzhou, a typical industrial city in the north of Jiangsu Province, was chosen to investigate the pollution level of atmospheric particulates. The proportion of fine particles (PM 2.5 ) in PM 10 is larger than that of coarse particles (about 58%). The physicochemical properties of PM 2.5 were analyzed by SEM and EDS. DGGE was used to study the distribution characteristics of bacterial community structure on atmospheric particulates (TSP, PM 2.5 and PM 10 ) in different functional areas of Xuzhou city during the winter haze. It was found that the microbial populations of atmospheric particles were mainly divided into three groups: Proteobacteria, Bacteroidetes, and Pachytenella. The community structure of bacteria in fine particle size was more abundant than that in coarse particle size. When haze occurs, the concentration of all kinds of pathogens in fine particle size will increase. Therefore, it is necessary to focus on the monitoring and management of fine particles.

Ultrafiltration (UF) processes exhibit high removal efficiencies for suspended solids and organic macromolecules, while UF membrane fouling is the biggest obstacle affecting the wide application of UF technology. To solve this problem, various pretreatment measures, including coagulation, adsorption, and advanced oxidation, for application prior to UF processes have been proposed and applied in actual water treatment processes. Previously, researchers mainly focused on the contribution of natural macromolecular pollutants to UF membrane fouling, while the mechanisms of the influence of emerging pollutants (EPs) in UF processes (such as antibiotics, microplastics, antibiotic resistance genes, etc.) on membrane fouling still need to be determined. This review introduces the removal efficiency and separation mechanism for EPs for pretreatments combined with UF membrane separation technology and evaluates the degree of membrane fouling based on the UF membrane’s materials/pores and the structural characteristics of the cake layer. This paper shows that the current membrane separation process should be actively developed with the aim of overcoming specific problems in order to meet the technical requirements for the efficient separation of EPs.

A powerful and promising route for developing chemically stable luminescent sensors for visible sensing of toxic pesticides in water and actual food samples is presented. Herein, a novel twofold interpenetrated luminescent metal–organic framework (MOF), Cd-TM, is prepared by incorporating 2-methyl-1H-imidazole-5-carbaldehyde as the imidazole-containing tridentate coordination linker and the luminescent organic bridging linker 4,4′,4″-tricarboxyltriphenylamine (H3tca) into a framework. Thanks to the imidazole coordination and structurally interpenetrated nature, the MOF exhibits high fluorescence stability and water stability up to 6 months. Fluorescence titration experiments reveal that Cd-TM shows rapid and ultrasensitive fluorescence response to p-nitroaniline compared with other nitroanilines with the limit of detection of about 8 nM. In particular, the Cd-TM material also shows high sensitivity to detect dicloran (DCN, 2,6-dichloro-4-nitroaniline) pesticides with the structure similar to that of p-NA. The detection limit is 7.6 nM, which is found to be superior to those of the recently reported MOF-based sensors. In addition, the detection mechanism of DCN is studied by FT-IR analysis, SEM/EDX elemental mapping, XPS, and theoretical calculations. Practically, the recoveries of spiked environmental samples were found to be satisfactory (95.8–106.4%). Further, Cd-TM is also used for the rapid in situ nondestructive imaging detection of pesticide residues in simulated fresh agricultural products. These results indicate that Cd-TM has the potential to detect organophosphorus pesticide contamination with rapid in situ imaging via easy-to-read visual signals.