Journal of hazardous materials最新文献

Microplastics (MPs) in biosolids used as soil amendments are of growing concern. The purpose of this study was to improve the characterization of MPs in complex biosolid matrices by optimizing sample preparation for morphological and chemical analyses with different spectroscopic techniques. We compared extraction procedures involving Fenton oxidation (F), Fenton plus sodium dodecyl sulfate (SDS), and Fenton plus cellulase (FE). We performed partial particle sample counting along with a helical shape, corresponding to 56 % of sample area, and total particle counting. Chemical characterization was performed using sub-micron optical-photothermal infrared (O-PTIR) spectroscopy, and the results were compared with those obtained via commonly employed Raman and Fourier transform infrared absorption microspectroscopy technique (µ-FTIR). Our FE protocol yielded a slightly higher total sample mass removal (97 %±0.3 %) compared to other pre-treatment methods. No significant difference was observed in the total MPs count between the two approaches, indicating a homogeneous distribution across the filter and supporting reliable quantification using only half the filter in the helical method. O-PTIR's high spatial resolution (down to 0.5 µm) and absence of spectral artefacts compared to Raman and µ-FTIR enabled accurate identification of fine fibers (2 µm wide) and small particles (∼5 µm). Single-frequency O-PTIR imaging revealed well-defined particles clearly separated from their surroundings, highlighting the technique's potential for particle identification. The findings highlight the need to combine effective sample pre-treatment with high-resolution chemical analysis to improve understanding of plastic fate in the environment and supporting future policy development or regulatory updates on plastic content in biosolids.

Background: Emerging plasticizers are increasingly detected in environmental and human biological samples, yet data regarding human exposure and associated health risks remain limited.

Objectives: This study uniquely assesses human exposure to emerging plasticizers by simultaneously quantifying 26 metabolites and 8 serum lipid biomarkers. It aims to explore their associations with lipid metabolism, providing new insights into the potential metabolic disruptions caused by these compounds.

Methods: Biomonitoring was conducted among 1514 participants from Jiangsu Province, Eastern China. Spearman's correlation was used to assess the influence of gender and age on metabolite levels. Generalized additive models examined associations between plasticizers and lipid biomarkers; quantile-based g-computation evaluated joint effects, and Bayesian benchmark dose analysis determined benchmark doses and hazard quotients.

Results: Six plasticizers, namely dibutyl fumarate (DBF), diethyl succinate (DES), trihexyl trimellitate (THTM), dimethyl adipate (DMA), and two isomers of diisobutyl adipate (DiBA & DnBA), were identified as significantly associated with lipid biomarkers, suggesting their potential to disrupt lipid metabolism. Notably, THTM was identified as a plasticizer that may pose a potential health risk to the general population (hazard quotient > 1), a finding not previously highlighted in the literature.

Conclusion: This study identifies six emerging plasticizers associated with lipid metabolism disruption, with THTM potentially posing a health risk. The simultaneous assessment of plasticizer metabolites and lipid biomarkers represents a novel approach that provides valuable insights for future research and risk management, particularly in low- and middle-income countries.

Polyethylene terephthalate (PET) is a widely used plastic whose poor degradability has led to serious environmental pollution. In recent years, it was shown that the engineered enzyme FAST-PETase can efficiently catalyze the hydrolysis of PET into monomers; however, large-scale production and low-cost application of this enzyme remain challenging. In this study, we successfully produced FAST-PETase at a large scale using the silk gland expression system of Bombyx mori and integrated an optimized FAST-PETase gene into the B. mori genome using genetic engineering technology. The content of recombinant FAST-PETase reached 53.3 mg per gram of cocoon weight, and approximately 22 % of which can be extracted using mild extraction conditions. The analysis revealed that rFAST-PETase, when extracted from cocoon crude extracts, efficiently and completely hydrolyzes PET plastics into terephthalic acid (TPA) and ethylene glycol (EG). Notably, the extraction method did not affect the spinning properties of the silk. Furthermore, a unique N-glycosylation modification of rFAST-PETase in the silkworm system was identified, which led to a significant enhancement in its thermostability. In comparison with conventional hydrolysis strategies for PET plastics, the cost of the proposed method is reduced by a minimum of 72 %, and the TPA hydrolysis product with 99 % purity can be recycled through an acid precipitation method. These findings indicate that this genetically engineered silk material has potential for use in PET plastic waste recycling.

Active species (AS) are key in Fenton/Fenton-like reactions. The unclear AS category and generation order of SO₄^•- and HO^• in the reaction of peroxymonosulfate (PMS) and Fe²⁺, as well as the quantity of SO₄^•- produced in the Fe²⁺/peroxydisulfate (PDS) system, limiting the practical application of selective AS generation for targeted pollutant degradation. Understanding the pathway of PMS/PDS/H₂O₂ activated by Fe²⁺ for SO₄^•-, HO^•, and Fe^Ⅳ generation is critical for the selective generation of AS by adjusting reaction conditions of pH or temperature. Results suggested that SO₄^•- was the sole PMS active product at T < 340 K and pH < 12, subsequently driving HO^• generation from H₂O, while Fe^ⅣO²⁺ was rapidly generated due to the chemical interaction between Fe²⁺ and PMS. In Fe²⁺/PDS system, one SO₄^•- instead of reputed two SO₄^•- was generated since the coactions of Fe²⁺ and SO₄ moiety, while Fe^ⅣO²⁺ is generated when H₂O acts as reactant at pH 0 -7. In Fe²⁺/H₂O₂ system, Fe^ⅣO²⁺ can only be formed stem from the pre-reaction of HO^• generation. Furthermore, Tuning the reactant concentration could convert the AS category. This work advances the cognition of Fenton/Fenton-like microcosmic reactions, and is positive to the future design of experimental and industrial processes.

Coupling heterogeneous photocatalysis with free chlorine (HOCl/ClO^-) emerges as an effective strategy to enhance the yield of reactive species, while the chlorine activation mechanism is yet to be clear. In this study, facet- and morphology-engineered BiVO₄ was synthesized and employed to activate HOCl/ClO^- under visible light irradiation, termed as Vis/BiVO₄/chlorine process. The HOCl/ClO^- activation mechanisms in the Vis/BiVO₄/chlorine process was investigated through use of of oxalate (hole (h_VB⁺) quencher) or Cu²⁺ (electron (e_CB^-) shuttle). e_CB^- and superoxide radicals (O₂^•-) activates HOCl to form hydroxyl radicals (HO•) (one-electron transfer pathways) while only reduces ClO^- to Cl^- (two-electron transfer pathways). O₂ not only promotes HO• production, but also enables more HO• to reach target compound without being scavenged. The reactions between h_VB⁺ and chlorine are both chlorine species- and valance band (VB) potential-dependent. h_VB⁺ activates both HOCl and ClO^- to form ClO•. While at pH 5.0, the more positive VB potential of BiVO₄ than the E°(Cl⁺/HOCl) enables h_VB⁺ to oxidize HOCl to HO• and Cl⁺, which reacts rapidly with H₂O to regenerate HOCl. Using truncated bipyramid-like BiVO₄ at larger exposed area of {110} facet (h_VB⁺-dominated) and plate-like BiVO₄ at larger exposed area of {010} facet (e_CB^-/O₂^•--dominated) favors the h_VB⁺- and e_CB^-/O₂^•--induced HOCl/ClO^- activation pathway, respectively. These findings provide novel insights into the chlorine activation mechanism and the modulation of reaction pathways that HOCl and ClO^- undergo and the corresponding radicals/ions.

Microorganisms critically regulate radionuclide migration through diverse biological mechanisms. Bacillus subtilis (B. subtilis) exhibits strong adsorption capacity, immobilizing radionuclides and limiting their mobility. By contrast, biological colloids predominantly enhance transport via complexation and mobilization. This study systematically investigates the influence of B. subtilis cells, spores, extracellular polymeric substances (EPS), and bentonite colloids (BC) on Eu(III) transport in quartz sand. Integrating advanced microscopy, spectroscopy, and machine learning, we reveal that Eu(III) mobility is governed by intricate interactions among bacterial activity, spores, EPS, and BC. Notably, inactivated B. subtilis colloids exhibited higher mobility yet more pronounced Eu(III) transport inhibition compared to live cells. Under neutral pH/low ionic strength conditions, B. subtilis cells and spores enhanced Eu(III) transport by 63 %, whereas acidic pH/high ionic strength conditions reduced transport by 30 % for cells, with spores maintaining elevated mobility. EPS removal increased both bacterial mobility and Eu(III) transport efficiency by 20 %, particularly under acidic conditions. While B. subtilis elevated Eu(III) mobility by 63 %, BC attenuated this effect by 13 %, primarily through the formation of BC-B. subtilis-Eu(III) ternary pseudo-colloids. Machine learning identified BC concentration and pH as key governing factors. These findings provide critical insights into microbial-mediated radionuclide transport and advance predictive risk assessment models for high-level radioactive waste disposal.

Viable pathogenic microorganisms in atmospheric particles pose notable health risks, while their exposure characteristics and health risks across climate zones remain unclear. This study collected 399 particulate samples from automobile air conditioning filters in eight Chinese cities across five climate zones, analyzing microbial concentration, viability, and pathogenicity via microbial culture, fluorescence staining, and high-throughput sequencing. Health risks were evaluated with quantitative microbial risk assessment (QMRA) method. Results revealed distinct microbial patterns. Proportion of viable microorganisms was highest in tropical monsoon climate region (42.58 %). Conversely, plateau and mountain climate region exhibited lower microbial viability (25.12 %) and bacterial culturability ((1.58 ± 0.41) × 10⁵ CFU/g). Bacterial genera like Acinetobacter were consistent across climate zones. However, dominant fungal genera manifested significant differences while pathogenic fungi such as Aspergillus and Cryptococcus were more abundant in temperate continental climate region. These may be attributed to different sources and microbial biogeographical characteristics, such as latitudinal distribution pattern. Annual infection risk and disease burden exceeds threshold of 10^-4 and 10^-6 in temperate, subtropical and tropical monsoon climate regions. Dermal contact demonstrated higher health risk. These insights into exposure characteristics of viable microorganisms can offer data support and theoretical basis for improving the air quality evaluation system and control of potential health risks.

Although methanogenic archaea are among the oldest microorganisms capable of mercury methylation, their contribution to methylmercury (MeHg) production has only recently gained attention. Studies with laboratory-cultivated methanogens elucidate the transformation of inorganic mercury (Hg) into MeHg, thereby uncovering underlying microbial methylation mechanisms. However, this field faces challenges such as significant Hg loss and unstable culture systems, which impede accurate assessment of these processes. This study aims to develop a reliable low-Hg-loss cultivation protocol for Hg methylation by methanogens, enabling a more accurate evaluation of their contribution to MeHg production. Our findings demonstrate that redox potential is a critical factor for Hg methylation, affecting Hg speciation and microbial growth. Notably, titanium nitrilotriacetate (Ti(III)-NTA), a reducing agent used in prior studies, was identified as a primary cause of Hg loss, reducing 83.2 % of Hg(II) to elemental Hg(0) at 500 μM. Adding cysteine satisfied both the redox and sulfur requirements of methanogens. Under these optimized conditions, Methanospirillum hungatei JF-1 achieved the highest MeHg production of all methanogens, converting 75.7 % of Hg(II) to MeHg and 630.4 pmol MeHg/mg protein. Overall, this study establishes a stable culture system for investigating Hg methylation by methanogens and indicates that the role of methanogens in mercury methylation is more substantial than previously acknowledged.

The engineering application of electro-Fenton process is subject to limited availability of •OH caused by mass transfer limitation and the short lifetime of •OH in water. In this study, an efficient electro-Fenton treatment process is developed by constructing a flow-through micro-nanoscale spatial confinement electrode with NiFe bimetal atom catalyst for oxygen reduction reaction (ORR). The NiN₄-FeN₄ active sites are anchored onto carbon nanotubes grown in the tunnel of carbonized pine wood (NiFe-NCNTs-CP). Efficient generation of •OH is achieved through 3-electron ORR over NiFe-NCNTs-CP. Because of the unique flow-through micron-nanoscale confinement environment, the concentration of accumulated •OH reaches as high as 6092 μmol L^-1 min^-1 even though the water flux is up to 236 L m^-2 h^-1 (equivalent to a retention time of 60 s). The proposed electro-Fenton system achieves 100 % removal of florfenicol, thiamphenicol, chloramphenicol, sulfamethoxazole, and tetracycline in water within just 60 s (C₀=20 mg L^-1, pH=7, 0.7 V vs SCE). The proposed continuous flow process maintains highly stable for treating actual medical wastewater within 8 days, achieving discharge standards and eliminating the antibacterial activity of medical wastewater. Furthermore, the proposed process showed a low energy consumption of only 7.35 kWh kg (COD)^-1. This study presents a highly practical electro-Fenton process for organic wastewater treatment.

Biochar derived from lignocellulosic biomass (LB) has shown broad application prospects in the field of peroxymonosulfate (PMS) catalysis, but the regulation mechanism of its catalytic active sites (e.g., C=O group) and LB components (cellulose, hemicellulose, and lignin) remains to be systematically elucidated. In this study, a laccase-mediated directional regulation strategy of LB components was innovatively proposed to target the design of biochar rich in the C=O group. Using wheat straw (WS) as a model feedstock, the properties and performance of biochar derived from native WS (BC-WS) and laccase-pretreated WS residue (BC-LR) were compared. Laccase pretreatment significantly enhanced the C=O group content of BC-LR by 213 %, achieved through a 27 % reduction in the relative lignin content and a corresponding increase in cellulose proportion. BC-LR demonstrated superior catalytic activity and reactive oxygen species yield than BC-WS in PMS activation, with strong positive correlations observed between its C=O content and phenol degradation kinetics (R²=0.9145) as well as PMS decomposition kinetics (R²=0.9957). Mechanistic investigations revealed that C=O-mediated non-radical pathway (including ¹O₂ and surface electron transfer) and adsorbed carbon transfer pathway dominated the phenol removal process in the BC-LR/PMS system. Notably, the BC-LR/PMS system exhibited broad-spectrum degradation of typical pollutants such as bisphenol F, o-phenylphenol, and naproxen. In addition, the system exhibited robust performance in dynamic remediation experiments under diverse hydrogeological conditions, achieving high efficiency in complex environments. This study elucidates the critical role of LB components in determining the C=O content and catalytic performance of biochar, providing a foundation for the tailored design of high-performance biochar for PMS catalytic environments.