MoS2 nanoflowers were synthesized via a temperature-controlled hydrothermal route (200 - 240 °C) to investigate the coupling among structural ordering, electronic disorder, and adsorption performance toward methylene blue (MB). The MS-240 sample exhibited the highest removal percentage 96.92% with an adsorption capacity of ∼12.92 mg g−1 within 20 min under low-concentration conditions (10 ppm) among the investigated samples. Structural and textural analyses revealed enhanced crystallinity, reduced interlayer spacing, and a mesoporous architecture (∼36.35 m2 g−1). These properties enable effective mass transport during adsorption. Optical studies demonstrate an increase in band gap (2.19 - 2.29 eV) and a decrease in Urbach energy (0.74 - 0.58 eV), indicating reduced electronic disorder. An inverse trend between Urbach energy and adsorption performance was observed within the investigated synthesis-temperature range. This indicates that reduced electronic disorder is one of several characteristics that co-evolve with synthesis temperature, and the Urbach energy serves as a complementary electronic descriptor for understanding adsorption behaviour rather than an independent causal parameter. Zeta potential measurements confirmed enhanced negative surface charge, strengthening electrostatic interactions with MB. Adsorption followed pseudo-second-order kinetics and the Freundlich isotherm, indicating heterogeneous surface-controlled adsorption. Thermodynamic parameters are consistent with a spontaneous, endothermic and predominantly physical adsorption process. These findings demonstrate that Urbach energy can serve as a complementary electronic descriptor for understanding adsorption behaviour and provide useful guidance for the design of MoS2-based adsorbents.
This study investigates trace element accumulation in the peregrine falcon (Falco peregrinus) at two contrasting sites in Italy, using a non-invasive multi-matrix approach based on feathers and faeces, integrated with environmental data from soil and well water. Individuals from Manfredonia and Orvieto were compared to assess both exposure during feather growth and recent dietary exposure. Soil analyses confirmed marked differences in geochemical contamination between the two sites, while well water showed more heterogeneous patterns. Trace element concentrations in feathers showed a consistent spatial pattern, with significantly higher levels in Manfredonia individuals for most elements, including mercury and lead. These differences may reflect enhanced dietary exposure and a potential trophic transfer, although prey items were not analyzed and facility-specific exposure factors cannot be excluded. In particular, mercury concentrations in feathers were markedly elevated in Manfredonia falcons, highlighting the potential value of feathers as indicators of exposure integrated during feather growth. Consistently, faecal analyses provided complementary information on recent exposure, with higher concentrations of several elements in Manfredonia individuals. The lack of significant differences for some elements may be hypothesized to reflect rapid excretion dynamics or physiological regulation, although these mechanisms were not experimentally investigated in the present study. The combined use of feathers and faeces provided complementary information that may be consistent with exposure during feather growth and recent dietary intake, although these exposure windows were not independently validated. The multi-matrix comparison revealed that feathers and soil exhibited the most consistent site-related differences, while faeces and water showed greater variability, reflecting distinct contamination and exposure dynamics. Overall, the results indicate that trace element exposure in raptors is associated with site-specific environmental conditions and suggest the potential use of peregrine falcons as bioindicators of terrestrial ecosystem contamination. This exploratory study provides a baseline for future investigations and highlights the value of non-invasive multi-matrix approaches for monitoring trace element exposure in terrestrial raptors.
In the present work, a novel magnetic ternary composite, MIL-100/MoS2/Fe3O4, was rationally designed and fabricated via a stepwise solvothermal method for the robust activation of peroxymonosulfate (PMS) toward tetracycline (TC) degradation. A combination of XRD, FT-IR, XPS, and FE-SEM provided comprehensive structural and morphological characterization of the composite. Electrochemical impedance spectroscopy (EIS) further suggested a reduced charge transfer resistance, potentially contributing to improved interfacial charge transfer. Compared to its individual components and binary counterparts, the composite demonstrated markedly superior catalytic activity, achieving 82.5% TC degradation within 5 min. Key operational parameters were systematically investigated. Radical quenching and EPR analyses revealed a synergistic radical/non-radical pathway, with singlet oxygen (1O2) playing a dominant role. Degradation intermediates were identified by LC-MS, enabling the proposal of transformation pathways, and an ECOSAR assessment indicated a reduction in ecological risk. Furthermore, the integrated Fe3O4 component enabled facile magnetic separation, with the catalyst retaining 77% activity after six cycles. The outstanding performance is attributed to the well-engineered heterostructure, which promotes efficient interfacial electron transfer and accelerates the Fe3+/Fe2+ redox cycle. This study provides a high-performance, magnetically recoverable catalyst and offers fundamental insights into the structure-activity relationship in MOF-based heterostructures for advanced oxidation processes.
