Combination of XEOL, TR-XEOL and HB-T interferometer at the TPS 23A X-ray nanoprobe for exploring quantum materials.

In this study, a combination of X-ray excited optical luminescence (XEOL), time-resolved XEOL (TR-XEOL) and the Hanbury-Brown and Twiss (HB-T) interferometer at the Taiwan Photon Source (TPS) 23A X-ray nanoprobe beamline for exploring quantum materials is demonstrated. On the basis of the excellent spatial resolution rendered using a nano-focused beam, emission distributions of artificial micro-diamonds can be obtained by XEOL maps, and featured emission peaks of a selected local area can be obtained by XEOL spectra. The hybrid bunch mode of the TPS not only provides a sufficiently high peak power density for experiments at each beamline but also permits high-quality temporal domain (∼200 ns) measurements for investigating luminescence dynamics. From TR-XEOL measurements, the decay lifetime of micro-diamonds is determined to be approximately 16 ns. Furthermore, the XEOL spectra of artificial micro-diamonds can be investigated by the HB-T interferometer to identify properties of single-photon sources. The unprecedented strategy of combining XEOL, TR-XEOL and the HB-T interferometer at the X-ray nanoprobe beamline will open new avenues with significant characterization abilities for unraveling the emission mechanisms of single-photon sources for quantum materials.

[Spatiotemporal Distribution and Pollution Risk Assessment of Heavy Metals in Sediments of Main Water Supply Reservoirs in Central Zhuhai City].

The Modaomen and Hongwan waterways are the main estuaries of the Pearl River system. Affected by tides, the Fenghuangshan Reservoir, Dajingshan Reservoir, and Zhuxiandong Reservoir, which are subject to water transfer along the river line, are important drinking water sources in the central part of Zhuhai City in the Guangdong-Hong Kong-Macao Greater Bay Area. Eight heavy metals in 15 sampling points in the reservoir area were monitored in the two seasons (August and October) of 2019. The environmental quality of the surface sediments of the three water supply reservoirs was surveyed using correlation analysis, geoaccumulation index evaluation, ecological risk assessment, and traceability analysis in the present study. The results showed that the order of the average content of the eight heavy metals in the three reservoirs was as follows: Zhuxiandong Reservoir>Dajingshan Reservoir>Fenghuangshan Reservoir. The contents of Hg, Zn, and Pb in Fenghuangshan Reservoir; Hg, As, Mn, Ni, Cu, Zn, and Pb in Dajingshan Reservoir; and Zhuxiandong Reservoir exceeded the background values of soil heavy metals in Guangdong province by 1.88-2.75, 1.05-2.32, and 1.69-6.45 times. Except for As in Fenghuangshan Reservoir, As and Cu in Dajingshan Reservoir and Cr and Ni in Zhuxiandong Reservoir, the other heavy metals elements showed the content characteristics of dry season>wet season. The evaluation results of the geoaccumulation index method indicated that the pollution degree of the three reservoirs was in the order of: Zhuxiandong Reservoir>Dajingshan Reservoir>Fenghuangshan Reservoir. Among them, the Fenghuangshan Reservoir and the Dajingshan Reservoir were only slightly polluted by Hg, Zn, and Pb elements, and the Zhuxiandong Reservoir as a whole was slightly or moderately polluted. The evaluation results of the potential ecological risk index showed that the overall ecological risk of Fenghuangshan Reservoir and Dajingshan Reservoir was low, and Zhuxiandong Reservoir was at a medium ecological risk level. Hg was the main ecological risk-contributing factor of the three reservoirs, with contribution rates of 78.8%, 64.4%, and 51.0%, respectively.

[Driving Factors Analyze of Phytoplankton Community by Comparison of Population and Functional Groups and Water Quality Evaluation in Dongting Lake].

Phytoplankton is the most important component of water ecosystems, which could indicate the state of the water environment owing to its sensitivity to water environment variation. However, its response to the environment is influenced by classification methods. To understand the phytoplankton population(phyla and genera) and functional groups(FG) for driving response characteristics and applicability to the environment in Dongting Lake, a total of four samples were collected from the lake from March to December 2019, and the distribution characteristics of the phytoplankton population and functional groups and their responses to environmental factors were compared and analyzed. Meanwhile, the applicability of the TLI index, Shannon-Wiener index, and Q index was compared in Dongting Lake. The results showed that a total of 61 genera belonging to six phyla of phytoplankton were detected in Dongting Lake, which could be divided into 23 functional groups and nine dominant functional groups. The succession trend of functional groups was P/MP/D(March)→MP/P/J(June)→MP/H1(September)→Y/P/MP(December). The results of hierarchical segmentation showed that the population distribution and change in phytoplankton were driven by environmental factors more than the area in Dongting Lake. The main environmental factors affecting phytoplankton population and functional groups were water temperature(WT), permanganate index, dissolved oxygen(DO), conductivity(Cond), water level(WL), and total phosphorus(TP). RDA analysis showed that phytoplankton functional groups identified phytoplankton response to environmental factors better than phytoplankton population. It was shown that using the Q index to evaluate water quality had better applicability in Dongting Lake.

[Pollution Characteristics and Risks of Polycyclic Aromatic Hydrocarbons in Underground and Surface Drinking Water Sources in Northeast Inner Mongolia].

Polycyclic aromatic hydrocarbons (PAHs) are hazardous and ubiquitous pollutants in the aquatic environment, and understanding the pollution characteristics and risk levels of PAHs is of great significance to the sustainable development of drinking water sources and drinking water safety. Hence, PAHs residues were measured qualitatively and quantitatively with solid-phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS) in 33 water samples (including 22 groundwater and 11 surface water samples) of the drinking water sources in the Manzhouli and Xinyouqi areas of northeast Inner Mongolia, and assessments of the pollution level of PAHs and the health and ecological risks were carried out. The results showed that PAHs were detected in all 33 sampling points of Manzhouli drinking water sources, except for benzo[k] fluoranthene, benzo[a] pyrene, and dibenzo[a,h] anthracene, with detection rates ranging from 36.36% to 95.45%; the detection rates of the other 13 PAHs monomers were 100%. The detection range of ρ（ΣPAHs） was 42.76-164.50 ng·L-1, and the mean value was 90.82 ng·L-1. The detection ranges of ρ（ΣPAHs） in surface water and groundwater were 66.39-164.50 ng·L-1 and 42.76-147.70 ng·L-1, respectively. The concentration of the detected naphthalene was the highest, with a mean value of 36.91 ng·L-1, and the concentration of anthracene was the lowest, with a mean value of 0.81 ng·L-1; there were no significant differences among the concentrations of all the PAHs monomers of the surface and groundwater (P>0.05). The pollution of PAHs was at a median level in China and abroad, mainly in the middle and low loops (3-4 loops). The analysis of the sources of PAHs in groundwater and surface water in Manzhouli using the ratio feature method and principal component analysis showed that the PAHs in the drinking water source water bodies in the Manzhouli area were mainly affected by the combustion of coal and biomass and oil, and some surface water sources were affected by the oil source. The human health and ecological risk assessment results showed that the water body of drinking water would not cause health risks to the human body, and the ecological risk was at a medium level; however, the high risk of benzo[b] fluoranthene (BbF) monomer production should be continuous cause for concern. From the perspective of the sustainable development of drinking water sources and drinking water safety, the necessary supervision and protection measures should be considered to prevent further pollution. The results of this research provide a scientific basis for the pollution control and prevention and control of PAHs in drinking water sources.

[Structural Characteristics of Phytoplankton Communities and Its Relationship with Environmental Factors in a Group of Drinking Water Reservoirs by Water Transmission from Modaomen Waterway in Zhuhai].

Modaomen Waterway is the main outlet of the Pear River system and an important water source for Zhuhai and Macao. The water quality of 13 sampling sites in Modaomen Waterway, phytoplankton, and environmental factors were investigated at 21 sampling sites in 4 drinking water source groups, which transport water from Modaomen Waterway and connect with each other, in August and October of 2021. A total of 73 genera of phytoplankton in eight phyla were identified, with a total of 150 species, most of them belonging to Cyanophyta, Chlorophyta, and Bacillariophyta. The relative abundance of Cyanophyta was higher than 90% in the DJS and YL reservoirs during flood and dry seasons; Cyanophyta, Chlorophyta, and Bacillariophyta were dominant phyla during different seasons; and their distribution was balanced in the ZXD and ZY reservoirs. The Shannon-Wiener index, Pielous uniformity index, and Margalef richness index showed that the ZY reservoir had the most abundant biodiversity, which indicated the best water quality, followed by the ZXD and YL reservoirs. Conversely, the DJS was the least diverse reservoir for phytoplankton. The PCoA analysis indicated significant differences in plankton structures in ZXD and ZY with the other two reservoirs (P<0.05), respectively. Redundancy analysis (RDA) showed that the main environmental factors affecting the distribution of the phytoplankton community were NO3-, TOC, TP, Cl-, and NH4+-N. These results indicated that the phytoplankton community of the four reservoirs were greatly affected by the nutrient salt caused by water transport, which suggested that the water quality of Modaomen Waterway should be improved to increase reservoir water nutrition to ensure the safety of drinking water sources.

Facile Microwave Hydrothermal Synthesis of ZnFe2O4/rGO Nanocomposites and Their Ultra-Fast Adsorption of Methylene Blue Dye.

The industry development in the last 200 years has led to to environmental pollution. Dyes emitted by pharmaceutical and other industries are major organic pollutants. Organic dyes are a pollutant that must be removed from the environment. In this work, we adopt a facile microwave hydrothermal method to synthesize ZnFe2O4/rGO (ZFG) adsorbents and investigate the effect of synthesis temperature. The crystal structure, morphology, chemical state, and magnetic property of the nanocomposite are investigated by X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and a vibrating sample magnetometer. Furthermore, the synthesized ZFGs are used to remove methylene blue (MB) dye, and the adsorption kinetics, isotherm, mechanism, and reusability of this nanomaterial are studied. The optimal ZFG nanocomposite had a dye removal percentage of almost 100%. The fitting model of adsorption kinetics followed the pseudo-second-order model. The isotherm model followed the Langmuir isotherm and the theoretical maximum adsorption capacity of optimal ZFG calculated by this model was 212.77 mg/g. The π-π stacking and electrostatic interaction resulted in a high adsorption efficiency of ZFG for MB adsorption. In addition, this nanocomposite could be separated by a magnet and maintain its dye removal percentage at almost 100% removal after eight cycles, which indicates its high suitability for utilization in water treatment.

One-Step Microwave-Assisted Synthesis and Visible-Light Photocatalytic Activity Enhancement of BiOBr/RGO Nanocomposites for Degradation of Methylene Blue.

In this study, bismuth oxybromide/reduced graphene oxide (BiOBr/RGO), i.e. BiOBr-G nanocomposites, were synthesized using a one-step microwave-assisted method. The structure of the synthesized nanocomposites was characterized using Raman spectroscopy, X-ray diffractometry (XRD), photoluminescence (PL) emission spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), and ultraviolet-visible diffuse reflection spectroscopy (DRS). In addition, the ability of the nanocomposite to degrade methylene blue (MB) under visible light irradiation was investigated. The synthesized nanocomposite achieved an MB degradation rate of above 96% within 75 min of continuous visible light irradiation. In addition, the synthesized BiOBr-G nanocomposite exhibited significantly enhanced photocatalytic activity for the degradation of MB. Furthermore, the results revealed that the separation of the photogenerated electron-hole pairs in the BiOBr-G nanocomposite enhanced the ability of the nanocomposite to absorb visible light, thus improving the photocatalytic properties of the nanocomposites. Lastly, the MB photo-degradation mechanism of BiOBr-G was investigated, and the results revealed that the BiOBr-G nanocomposites exhibited good photocatalytic activity.