In this study, a microbial fuel cell was constructed using Raoultella sp. XY-1 to efficiently degrade tetracycline (TC) and assess the effectiveness of the electrochemical system. The degradation rate reached 83.2 ± 1.8 % during the 7-day period, in which the system contained 30 mg/L TC, and the degradation pathway and intermediates were identified. Low concentrations of TC enhanced anodic biofilm power production, while high concentrations of TC decreased the electrochemical activity of the biofilm, extracellular polymeric substances, and enzymatic activities associated with electron transfer. Introducing electrogenic bacteria improved power generation efficiency. A three-strain hybrid system was fabricated using Castellaniella sp. A3, Castellaniella sp. A5 and Raoultella sp. XY-1, leading to the enhanced TC degradation rate of 90.4 % and the increased maximum output voltage from 200 to 265 mV. This study presents a strategy utilizing tetracycline-degrading bacteria as bioanodes for TC removal, while incorporating electrogenic bacteria to enhance electricity generation.

Due to the significant POPs characteristics, dioxins caused concern in public health and environmental protection. Evaluating the toxicity risk of dioxin degradation pathways is critical. OCDD, 1,2,3,4,6,7,8-HpCDD, and 1,2,3,4,6,7,8-HpCDF, which are highly abundant in the environment and have strong biodegradation capabilities, were selected as precursor molecules in this study. Firstly, their transformation pathways were deduced during the metabolism of biometabolism, microbial aerobic, microbial anaerobic, and photodegradation pathways, and density function theory (DFT) was used to calculate the Gibbs free energy to infer the possibility of the occurrence of the transformation pathway. Secondly, the carcinogenic potential of the precursors and their degradation products was evaluated using the TOPKAT modeling method. With the help of the positive indicator (0-1) normalization method and heat map analysis, a significant increase in the toxic effect of some of the transformation products was found, and it was inferred that it was related to the structure of the transformation products. Meanwhile, the strength of the endocrine disrupting effect of dioxin transformation products was quantitatively assessed using molecular docking and subjective assignment methods, and it was found that dioxin transformation products with a higher content of chlorine atoms and molecules similar to those of thyroid hormones exhibited a higher risk of endocrine disruption. Finally, the environmental health risks caused by each degradation pathway were comprehensively assessed with the help of the negative indicator (1-2) standardization method, which provides a theoretical basis for avoiding the toxicity risks caused by dioxin degradation transformation. In addition, the 3D-QSAR model was used to verify the necessity and rationality of this study. This paper provides theoretical support and reference significance for the toxicity assessment of dioxin degradation by-products from inferred degradation pathways.

Presently, the hydroxyl radical oxidation mechanism is widely acknowledged for the degradation of organic pollutants based on hydrodynamic cavitation technology. The presence and production mechanism of other potential reactive oxygen species (ROS) in the cavitation systems are still unclear. In this paper, singlet oxygen (1O2) and superoxide radical (·O2-) were selected as the target ROS, and their generation rules and mechanism in vortex-based hydrodynamic cavitation (VBHC) were analyzed. Computational fluid dynamics (CFD) were used to simulate and analyze the intensity characteristics of VBHC, and the relationship between the generation of ROS and cavitation intensity was thoroughly revealed. The results show that the operating conditions of the device have a significant and complicated influence on the generation of 1O2 and ·O2-. When the inlet pressure reaches to 4.5 bar, it is more favorable for the generation of 1O2 and ·O2- comparing with those lower pressure. However, higher temperature (45 °C) and aeration rate (15 (L/min)/L) do not always have positive effect on the 1O2 and ·O2- productions, and their optimal parameters need to be analyzed in combination with the inlet pressure. Through quenching experiments, it is found that 1O2 is completely transformed from ·O2-, and ·O2- comes from the transformation of hydroxyl radicals and dissolved oxygen. Higher cavitation intensity is captured and shown more disperse in the vortex cavitation region, which is consistent with the larger production and stronger diffusion of 1O2 and ·O2-. This paper shed light to the generation mechanism of 1O2 and ·O2- in VBHC reactors and the relationship with cavitation intensity. The conclusion provides new ideas for the research of effective ROS in hydrodynamic cavitation process.

Municipal sludge contains abundant amounts of carbon, with contents ranging from 14 % to 38 %. The various carbon-containing group compounds can be converted into beneficial products, but pollutants and greenhouse gases are also released through the municipal sludge pyrolysis process. Ascertaining the pathways by which carbon-containing group compounds is converted and transformed is crucial for addressing pollution concerns and promoting recycling. This study explored the transformation pathways of carbon-containing group compounds during the pyrolysis process of municipal sludge. The results showed that the three major carbon-containing group compounds including protein (61 %), cellulose (9 %), and hemicellulose (7 %), had significantly different pyrolysis temperature of 600 °C, 400 °C and 300 °C. In terms of gas pollution, most carbon was fully pyrolyzed into CO2. While the temperature raised up to 500 °C, a part of the CO2 converted into CO. Meanwhile, the various carbon-containing compounds exhibited distinct effects on gas production, which CH4 was produced more with cellulose and protein presenting in the sludge. When temperature increased to 700 °C, the 60 % of the carbon-containing group compounds were transformed into liquid and solid. The pyrolysis liquid in the low-temperature stage (30-300 °C) contained a relatively high aliphatics content and lower organooxygen species (OOSs) content (at 200 °C), suggesting a potential for resource utilization. The yield of CO in the gas rapidly increased as the temperature increased in the high-temperature stage (500-700 °C). The insights from this study hold practical implications for enhancing municipal sludge pyrolysis efficiency, reducing pollution, and facilitating more sustainable and resource-efficient practices.

The semiconductor industry has claimed that perfluorooctanesulfonate (PFOS), a persistent per- and polyfluoroalkyl substance (PFAS), has been eliminated from semiconductor production; however, information about the use of alternative compounds remains limited. This study aimed to develop a nontarget approach to discovering diverse PFAS substitutions used in semiconductor manufacturing. A distinct fragment-based approach has been established to identify the hydrophobic and hydrophilic features of acidic and neutral fluorosurfactants through fragments and neutral losses, including those outside the homologous series. Ten sewage samples from 5 semiconductor plants were analyzed with target and nontarget analysis. Among the 20 identified PFAS spanning 12 subclasses, 15 were reported in semiconductor sewage for the first time. The dominant identified PFAS compounds were C4 sulfonamido derivatives, including perfluorobutane sulfonamido ethanol (FBSE), perfluorobutane sulfonamide (FBSA), and perfluorobutane sulfonamido diethanol (FBSEE diol), with maximum concentrations of 482 μg/L, 141 μg/L, and 83.5 μg/L in sewage, respectively. Subsequently, three ultrashort chain perfluoroalkyl acids (PFAAs) were identified in all samples, ranging from 0.004 to 19.9 μg/L. Three effluent samples from the associated industrial wastewater treatment plants (WWTPs) were further analyzed. This finding, that the C4 sulfonamido acetic acid series constitutes a significant portion (65%-82%) of effluents from WWTP3 and WWTP4, emphasizes the conversion of fluorinated alcohols to fluorinated acids during aerobic treatment. The identification of the intermediate metabolites of FBSEE diol, further supported by our laboratory batch studies, prompts the proposal of a novel metabolic pathway for FBSEE diol. The total amount of perfluorobutane sulfonamido derivatives reached 1934 μg/L (90%), while that of PFAAs, which have typically received attention, was only 205 μg/L (10%). This suggests that perfluorobutane sulfonamido derivatives are emerging as a new trend in fluorosurfactants used in the semiconductor industry, serving as PFAS precursors and contributing to the release of their metabolites into the environment.

Per- and polyfluoroalkyl substances (PFASs) have raised significant concerns within the realm of drinking water due to their widespread presence in various water sources. This prevalence poses potential risks to human health, ecosystems, and the safety of drinking water. However, there is currently a lack of comprehensive reviews that systematically categorize the distribution characteristics and transformation mechanisms of PFASs in drinking water sources. This review aims to address this gap by concentrating on the specific sources of PFASs contamination in Chinese drinking water supplies. It seeks to elucidate the migration and transformation processes of PFASs within each source, summarize the distribution patterns of PFASs in surface and subsurface drinking water sources, and analyze how PFASs molecular structure, solubility, and sediment physicochemical parameters influence their presence in both the water phase and sediment. Furthermore, this review assesses two natural pathways for PFASs degradation, namely photolysis and biodegradation. It places particular emphasis on understanding the degradation mechanisms and the factors that affect the breakdown of PFASs by microorganisms. The ultimate goal is to provide valuable insights for the prevention and control of PFAS contamination and the assurance of drinking water quality.

UV/Peracetic Acid (UV/PAA), as an innovative advanced oxidation process (AOP), is employed to treat bisphenol A (BPA) in water through the generation of hydroxyl radicals (•OH) and carbon-centered radicals (R-C•). The impact of halide ions (Cl-; Br-; I-) on the efficiency of UV/PAA was investigated for the first time under varying pH levels. The presence of halide ions exerted an influence on the reactivity of •OH and R-C•, exhibiting varying degrees of impact across different pH conditions. It was discovered that pH exerts a significant influence on its efficiency, with optimal removal performance observed at a pH 9. The degradation of BPA was inhibited by Cl- through the generation of reactive chlorine species (RCS), which triggers the interconversion between •OH and R-C•. Reactive bromine species (RBS) were produced in the presence of Br-, facilitating BPA degradation and generating HOBr as a supplementary source of •OH radicals. I- primarily generate reactive iodine species (RIS) through photolysis, which facilitates the degradation of BPA. The transformation of BPA involves hydroxylation, demethylation, halogenation, and cleavage reactions to form various products and pathways. The toxicity test demonstrates that the UV/PAA treatment of BPA exhibits lower toxicity, thereby indicating its environmentally friendly.

Raphani Semen (RS) encompasses two distinct application forms in Chinese clinical practice: raw RS (RRS) and stir-fried RS (SRS). They exhibit divergent drug properties and effects, as described in traditional Chinese medicine theory known as \"Sheng shu yi zhi, sheng sheng shu jiang\". The dissimilarity in RS\'s drug properties is intrinsically linked to alterations in its internal components during the stir-frying process. Previous studies have demonstrated that stir-frying renders myrosinase inactive, thereby preventing the enzymatic hydrolysis of glucosinolates in RS. However, the precise enzymatic hydrolysis pathway and products of glucosinolates remain unclear. Furthermore, it remains uncertain whether other components undergo changes influenced by endogenous enzymes. The objective of this study is to systematically analyze the chemical components disparities between RRS and SRS using high-performance liquid chromatography coupled with time-of-flight mass spectrometry (HPLC-TOF-MS). Additionally, it seeks to elucidate the potential transformation pathways of multiple components from an enzymatic hydrolysis perspective. We have developed a sensitive and efficient high-performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (HPLC-QQQ-MS) method for quantifying the content of 5 characteristic components, including glucoraphenin, sinapine thiocyanate, sulforaphene, sinapic acid, and 3\',6-disinapoylsucrose. Based on retention time and MS spectra, we have identified 19 characteristic components in both SRS and RRS, encompassing glucosinolates and sulfur-containing derivatives, oligosaccharide esters, and small-molecule phenolic acids. Notably, 18 of these components undergo changes during the enzymatic hydrolysis process, leading to the identification of 4 transformation pathways: glucoraphenin, 6-sinapoylglucoraphenin, 3\',6-disinapoylsucrose and β-D-(3,4-disinapoyl) furanofructosyl-α-D-(6-sinapisoyl) glucoside, along with 3\'-O-sinapoyl-6-O-feruloylsucrose. Quantitative analysis reveals significant differences, including lower levels of glucoraphenin in RRS compared to SRS, higher sulforaphene and sinapic acid levels in RRS, while sinapine thiocyanate and 3\',6-disinapoylsucrose remain unchanged before and after stir-frying. The results of this study highlight distinct chemical compositions between RRS and SRS. Additionally, the method of characterization and content determination constructed in this paper has strong practical value and provides a useful approach for comprehensively evaluating the chemical composition and quality of RS.

Clarifying the antibacterial mechanism of silver (Ag)-based materials is of great significance for the rational design, synthesis, and evaluation of antimicrobials. Herein, detailed description of the antibacterial mechanism of a synthesized silver deposited fullerene material (Ag(I)-C60) towards Staphylococcus aureus was surveyed from the point of view of DNA damage by ultraviolet-visible spectroscopy (UV-vis), inductively coupled plasma mass spectrometry (ICP-MS), and liquid chromatography-mass spectrometry (LC-MS). The model material, Ag(I)-C60, was prepared by liquid-liquid interfacial precipitation method, and characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), thermos-gravimetric analysis (TGA), and nitrogen adsorption/desorption analysis. Ultra-efficient bacteriostatic rate of Ag(I)-C60 was found to be 88.98% under light irradiation for 20 min. UV-vis measurement of the composition changes of four DNA bases showed that they changed in the presence of Ag(I)-C60 under light irradiation, suggesting Ag(I)-C60 could destroy the cells and genetic material of Staphylococcus aureus and thereby inhibit its growth and reproduction. ICP-MS analysis demonstrated the releasing behavior of Ag+ from Ag-based materials. Finally, the transformation pathway of G, A, C, and T were measured by LC-MS, demonstrating the conversion of Adenine (m/z 136.06) to 8-OH-Ade (m/z 174.04). These collective results suggested that Ag(I)-C60 was a new ultra-efficient antibacterial by slowly releasing Ag+ in water and producing a large amount of ROS under light.

Colloidal semiconductor II-VI metal chalcogenide (ME) magic-size clusters (MSCs) exhibit either an optical absorption singlet or doublet. In the latter case, a sharp photoluminescence (PL) signal is observed. Whether the PL-inactive MSCs transform to the PL-active ones is unknown. We show that PL-inactive CdS MSC-322 transforms to PL-active CdS MSC-328 and MSC-373 in the presence of acetic acid (HOAc). MSC-322 displays a sharp absorption at ≈322 nm, whereas MSC-328 and MSC-373 both have broad absorptions respectively around 328 and 373 nm. In a reaction of cadmium myristate and S powder in 1-octadecene, MSC-322 develops; with HOAc, MSC-328 and MSC-373 are present. We propose that the MSCs evolve from their relatively transparent precursor compounds (PCs). The PC-322 to PC-328 quasi-isomerization involves monomer substitution, while monomer addition occurs for the PC-328 to PC-373 transformation. Our findings suggest that S dominates the precursor self-assembly quantitatively, and ligand-bonded Cd mainly controls MSC optical properties.