In situ surface-enhanced Raman spectroscopy for the detection of nanoplastics: A novel approach inspired by the aging of nanoplastics.

Nanoplastics (NPs) present a hidden risk to organisms and the environment via migration and enrichment. Detecting NPs remains challenging because of their small size, low ambient concentrations, and environmental variability. There is an urgency to exploit detection approaches that are more compatible with real-world environments. Herein, this study provides a surface-enhanced Raman spectroscopy (SERS) technique for the in situ reductive generation of silver nanoparticles (Ag NPs), which is based on photoaging-induced modifications in NPs. The feasibility of generating Ag NPs on the surface of NPs was derived by exploring the photoaging mechanism, which was then utilized to SERS detection. The approach was applied successfully for the detection of polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET) NPs with excellent sensitivity (e.g., as low as 1 × 10-6 mg/mL for PVC NPs, and an enhancement factor (EF) of up to 2.42 × 105 for small size PS NPs) and quantitative analytical capability (R2 > 0.95579). The method was successful in detecting NPs (PS NPs) in lake water. In addition, satisfactory recoveries (93.54-105.70 %, RSD < 12.5 %) were obtained by spiking tap water as well as lake water, indicating the applicability of the method to the actual environment. Therefore, the proposed approach offers more perspectives for testing real environmental NPs.

High sensitivity in quantitative analysis of mixed-size polystyrene micro/nanoplastics in one step.

As emerging environmental pollutants, microplastics (MPs) and nanoplastics (NPs) pose a serious threat to human health. Owing to the lack of feasible and reliable analytical methods, the separation and identification of MPs and NPs of different sizes remains a challenge. In this study, a hyphenated method involving filtration and surface-enhanced Raman spectroscopy (SERS) for the separation and identification of MPs and NPs is reported. This method not only avoids the loss of MPs and NPs during the transfer process but also provides an excellent SERS substrate. The SERS substrate was fabricated by electrochemically depositing silver particles onto the reduced graphene oxide layer coated on stainless steel mesh. Results show that polystyrene (PS) MPs and NPs are efficiently separated on the SERS substrate via vacuum filtration, resulting in high retention rates (74.26 % ± 1.58 % for 100 nm, 81.06 % ± 1.49 % for 500 nm, and 97.73 % ±0.11 % for 5 µm) and low limit of detection (LOD). The LOD values of 100 nm, 500 nm, and 5 µm PS are 8.89 × 10-5, 3.39 × 10-5, and 1.57 × 10-4 µg/mL, respectively. More importantly, a linear relationship for uniform quantification of 100 nm, 500 nm, 3 µm and 5 µm PS was established, and the relationship is Y = 225.61 lgX + 1076.36 with R2 = 0.980. The method was validated for the quantitative analysis of a mixture of 100 nm, 500 nm PS NPs, 3 µm and 5 µm PS MPs in a ratio of 1:1:1:1, which successfully approaches the evaluation of evaluated PS NPs in the range of 10-4-10 µg/mL with an LOD value of approximately 7.82 × 10-5 µg/mL. Moreover, this method successfully detected (3.87 ± 0.06) × 10-5 µg MPs and NPs per gram of oyster tissue.

Preparation of hollow tubular TpBD COF and pod-like ZIF-8/H-TpBD COF tubes using a porous anodic aluminum oxide membrane as template.

By sacrificing a porous anodic aluminum oxide (AAO) membrane as a template, hollow tubular TpBD (H-TpBD) covalent organic framework (COF) tubes were synthesized in situ and zeolitic imidazolate framework (ZIF-8) nanoparticles were creatively synthesized in situ in H-TpBD tubes at room temperature. H-TpBD COF tubes and ZIF-8/H-TpBD COF tubes were procured by using a strong base or acid to remove the AAO membrane. Then they were analyzed by X-ray diffraction, Fourier infrared spectroscopy, scanning electron microscope, transmission electron microscope, etc. Surprisingly, the obtained TpBD COF has a very small aperture (1.8 nm), thinner tube thickness (50 nm), high stability, and a smooth and homogeneous surface. And the pod-like ZIF-8/H-TpBD COF with complete tubular structure was also obtained.

Data of temperature, thermal conductivity, heat production and heat flow of the southern Tan-Lu Fault Zone, East-Central China.

In this article we report 5 terrestrial heat flow points along the southern Tan-Lu Fault Zone based on the first systematic deep borehole temperature measurements and thermal conductivities of 128 rock samples. All the temperature logs after 1 m spacing is plotted. The thermal properties test data of all samples have been collated separately, and the thermal conductivity correction data for different depths is presented. In combination with steady state temperature and thermal properties testing, the vertical variation of heat flow is calculated. Detailed interpretation of this data can be found in a research article titled "Heat flow, heat production, thermal structure and its tectonic implication of the southern Tan-Lu Fault Zone, East-Central China" (Wang et al., 2019) [1].

[Relationships between grazing-path and Berberis aggregate population characteristics in upper reaches of Minjiang River, Southwest China].

Taking the Berberis aggregate shrubs in the ecotone of dry valley and montane forests in upper reaches of Minjiang River as study objects, and by the methods of tracking grazing and field survey, this paper studied the characteristics of habitat utilization by livestock and the features of grazing-path. The major factors affecting the features of grazing-path were screened by redundancy analysis (RDA), and the relationships of the grazing-path features with the coverage, size class, and distribution pattern of the shrubs were analyzed. It was shown that the distribution pattern of the grazing-path could intuitively reflect the characteristics of the habitat utilization by livestock, being in accordance with the results of tracking grazing. The Morisita index at 5 m scale could objectively reflect the distribution type of the grazing-path. Sample plots 1, 2 and 6 presented a contagious distribution of grazing-path, while the other plots showed regular distribution. In slope scale, the coverage and height of the shrubs were the notable affecting factors, which had negative correlations with the grazing-path features. There was a significant negative correlation between the coverage of B. aggregate population and the area of grazing-path. The population structure of B. aggregate had a close correlation with the distribution of grazing-path. The ratio of the long axis to short axis of the shrubs was averagely 1.29, and the shape of the shrubs approached to round. It was considered that the grazing-path landscape and the livestock on the grazing-paths had the function of reconstructing the shape of the shrubs. The directionality of the population pattern of B. aggregate was generally in line with the distribution type of grazing-path, but actually, they were opposite in distribution. The patches of the shrubs were in aggregated or uniform distribution in the areas deviated from the grazing-path.