Per- and polyfluoroalkyl substances (PFAS) accumulate in municipal sewage sludge and biosolids, creating a potential source of environmental release following land application. This study evaluated two sorbents, RemBind100 and RemBind100X, for limiting PFAS release from sludge-derived pellets. Bench-scale experiments were conducted using samples collected at different stages of the sludge-processing train and spiked with a mixture of 10 PFAS. Amendment performance was evaluated using the U.S. EPA Synthetic Precipitation Leaching Procedure to assess PFAS leachability and U.S. EPA Method 1633A extraction to assess PFAS-sorbent binding strength. RemBind100X outperformed RemBind100, reducing Σ10PFAS leachability of 78.81±1.32% and 91.48±2.64% at 0.3% and 0.6% (w/w), respectively. Extractable Σ10PFAS also decreased by up to ~50% with increasing amendment dosage, indicating stronger PFAS retention. Amendment addition at the raw sludge stage provided the greatest immobilization efficiency compared to later stages of sludge processing. Short-term aging and sequential leaching tests demonstrated sustained PFAS retention. Both amendments also reduced the leachability of background ultrashort-chain PFAS present in sludge, indicating applicability to highly mobile PFAS species. These findings demonstrate the potential of sorbent amendments to reduce PFAS mobility in municipal sludge-derived pellets and highlight the influence of amendment dosage and point of amendment addition during sludge-processing on PFAS immobilization.
The rapid expansion of lithium-ion battery technologies has markedly increased global demand for nickel (Ni), cobalt (Co), and manganese (Mn), critical components of layered LiNixCoyMnzO2 (NCM) cathode materials used in new energy vehicles and energy storage systems. Although these energy-transition metals are indispensable for decarbonization efforts, their intensified extraction, refining, manufacturing, recycling, and disposal raise growing concerns regarding occupational and environmental exposure. Increasing evidence indicates that Ni, Co, and Mn induce diverse adverse health effects, including neurotoxicity, reproductive dysfunction, pulmonary injury, and metabolic disorders, primarily through disruption of redox homeostasis. Beyond the well-established roles of oxidative stress, mitochondrial dysfunction, and DNA damage, emerging studies identify N6-methyladenosine (m⁶A) RNA modification as a critical post-transcriptional mechanism underlying metal-induced toxicity. As the most abundant internal modification in eukaryotic messenger RNA, m⁶A dynamically regulates RNA splicing, stability, translation, and degradation through coordinated actions of methyltransferases ("writers"), demethylases ("erasers"), and m⁶A-binding proteins ("readers"). Exposure to Ni, Co, and Mn alters the expression and activity of key m⁶A regulators, including METTL3, METTL14, METTL16, FTO, ALKBH5, YTHDF proteins, and YTHDC family members, leading to widespread epitranscriptomic reprogramming. Here, we synthesize current evidence demonstrating that these metals exploit m⁶A-dependent pathways to drive neuroinflammation, ferroptosis, autophagy impairment, mitochondrial dysfunction, aberrant iron metabolism, defective spermatogenesis, ribosome biogenesis disorders, and malignant transformation. We further highlight the bidirectional interplay between m⁶A signaling and redox-responsive pathways, including hypoxia-inducible factor signaling, oxidative stress responses, and mitochondrial quality control. Collectively, this review positions m⁶A modification as a redox-sensitive regulatory hub linking exposure to critical battery metals with adverse health outcomes. Elucidating m⁶A-mediated mechanisms may facilitate the identification of novel biomarkers for mitigating health risks associated with the accelerating global transition toward electrification.
Personal care products (PCPs) and hair care products (HCPs) are well-established sources of indoor airborne nanoparticles and volatile organic compounds (VOCs), yet emissions from propellant-based aerosol HCPs, including the rapidly growing class of dry shampoos, remain poorly characterized in residential use scenarios. Here, we present real-time, breathing zone measurements of particle- and gas-phase emissions during the use of five commercially available propellant-based aerosol HCPs (four dry shampoos and one hair shine spray) in a full-scale, mechanically ventilated residential test house. Particle aerodynamic size distributions from 6nm to 10µm were resolved at 1Hz with a high-resolution electrical low-pressure impactor (HR-ELPI+), enabling continuous tracking of nanoparticle emissions, growth, and decay. Total VOC (TVOC) mixing ratios were monitored in parallel using a photoionization detector (PID) at 5s resolution. Across 14 well-mixed experiments, dry shampoo application generated breathing zone size-integrated nanoparticle number concentrations of 103–104cm-3 with peaks reaching ~105cm-3. Sub-100 nm nanoparticles, on average, accounted for ~92% of total number concentrations, and over half of the detected nanoparticles had aerodynamic diameters below 20nm. Concurrent peak TVOC mixing ratios reached up to ~5 × 103 ppb. Under non-mixed conditions representative of small bathroom enclosures, breathing zone peak number concentrations reached up to ~8 × 105cm-3 and TVOC mixing ratios reached up to ~2 × 104 ppb. These findings identify dry shampoo use as a significant, previously underexamined indoor source of breathing zone nanoparticles and co-emitted VOCs, with direct implications for indoor air quality and inhalation exposure assessment.
Pesticide contamination of water resources poses significant environmental and public health risks. This study presents a novel application of a visible light-activated titanium carbide core — titanium dioxide shell (TiC@TiO₂) nano-photocatalyst for the degradation of the neonicotinoid pesticide imidacloprid, evaluated against the benchmark Degussa P25 TiO₂ under both UV-C and simulated sunlight irradiation. The TiC@TiO₂ core-shell architecture enables visible light absorption through a narrowed effective band gap (2.93 eV vs. 3.25 eV for P25 TiO₂). Degradation kinetics followed the Langmuir-Hinshelwood model at varying initial concentrations (50–600 mg/L), transitioning to pseudo-first-order behavior as the reaction progressed. Under UV-C irradiation, TiC@TiO₂ achieved 83.5% imidacloprid degradation within 90 min (kapp = 0.0135 min⁻¹), significantly outperforming P25 TiO₂ (70.0%, kapp = 0.0081 min⁻¹). Under simulated sunlight, TiC@TiO₂ achieved 64.7% degradation (kapp = 0.0077 min⁻¹), a result not significantly different from P25 performance under UV-C irradiation (kapp = 0.0081 min⁻¹, p > 0.05). Hydroxyl radical generation under both light sources was confirmed by electron paramagnetic resonance (EPR) spectroscopy. Using a novel solid-phase microextraction arrow (SPME-Arrow) coupled GC-MS method developed in this study, twenty degradation products were identified, and a photocatalytic degradation pathway was proposed. These results demonstrate that TiC@TiO₂ represents a promising visible-light-driven photocatalyst for pesticide remediation in water treatment applications.
We report a large-scale study investigating the arsenometabolome in 93 various wild mushroom species collected from natural environments. Arsenocarnitine was discovered as a novel arsenic compound previously unreported in nature and an analogue of carnitine which is a key amino acid that plays a central role in all domains of life. Identification was based on a combination of element-selective and molecular mass spectrometry and unambiguously validated by chemical synthesis. Arsenocarnitine was found to be ubiquitous with concentrations up to 147 µg As kg⁻¹ and its abundance showed a significant positive correlation with carnitine. Two highly distinct types of the mushroom species in terms of arsenic biotransformation patterns were observed, type (-) characterized by dominance of methylated anionic arsenic, and type (+) characterized by an astonishingly complex arsenometabolome tagged with the quaternary arsonium functional group. Arsenocarnitine was clearly associated with type (+) mushrooms and largely undetectable in type (-) mushrooms. The discovery of arsenocarnitine expands the narrow chemical space of natural organoarsenic compounds beyond conventional structures and provides new insights into the close relationship between arsenic and nitrogen. The distinct types of arsenometabolomes suggest variable fate of arsenic in our environment which has been underrecognized.
Leachate from municipal landfills is a major source of per- and polyfluoroalkyl substances (PFAS) to groundwater. This study presents field-scale evidence of PFAS generation, release, and downward migration in a closed landfill comprising a 15 m waste body overlying a 16 m sandy unsaturated zone. PFAS composition and transport were monitored using a vadose zone monitoring system, with monthly leachate and porewater sampling over six months (November 2022–April 2023). Analysis of leachate samples shows short-chain perfluoroalkyl carboxylic acids (PFCAs), particularly PFBA, PFPeA, and PFHxA, dominate leachate and are preferentially released from decomposing waste, subsequently migrating through the unsaturated zone. In contrast, long-chain PFAS (PFOS, PFNA) and the precursor 6:2 FTS persist in shallow waste (<5 m) but are absent in deeper waste profiles, indicating in-waste transformation. Deeper waste layers and the underlying unsaturated zone show attenuation of long-chain compounds and enrichment of mobile short-chain species. Hydrological data indicate a transition from preferential flow in the waste to matrix-dominated flow in the sandy vadose zone, with episodic infiltration pulses governing PFAS transport. Overall, these findings demonstrate that landfills act as long-term, depth-stratified PFAS sources, where coupled hydrological and biogeochemical processes control the mass pollution potential of PFAS and associated groundwater risks.
Radioactive strontium is a priority contaminant in nuclear wastewater because of its high environmental mobility and long-term health risks. In this study, a Bacillus cereus strain, BC-11, was isolated from soil surrounding an irradiation facility. BC-11 maintained growth under Sr2+ stress and exhibited optimal adsorption at pH 7.0, 30℃, 150 rpm, and a biomass dosage of 100 mg. The Langmuir model best described the adsorption isotherm, with a theoretical maximum adsorption capacity of 26.1 mg/g, suggesting monolayer adsorption on finite and specific active sites. Sr2+ adsorption followed the pseudo-second-order model, indicating that chemisorption dominated the uptake process. SEM-EDS confirmed progressive Sr accumulation on the bacterial surface, while FTIR analysis showed that carboxyl, phosphate, hydroxyl, amino, and amide groups participated in Sr2+ fixation through surface complexation and ion exchange. Proteomic analysis suggested that BC-11 regulated cell wall remodeling, secretion systems, ABC transporters, and energy metabolism to control strontium transport. This study identifies a radiation-resistant Bacillus cereus strain with efficient Sr2+ adsorption, highlighting its potential for remediating radioactive strontium-contaminated wastewater.
Phenolic pollutants such as 4-chlorophenol (4-CPh), 4-chloro-3,5-dimethylphenol (PCMX), and 2,6-dimethylphenol (2,6-DMP) are toxic and persistent organic contaminants that pose serious environmental and health concerns due to their low biodegradability and high chemical stability. In this work, the roles of the functional groups and the framework flexibility of the MIL-53 derivative metal–organic frameworks (MOFs) in the adsorption-based removal of phenolic pollutants were systematically investigated. Structural characterization confirmed the flexible breathing nature of MIL-53(Al), whereas NH2-MIL-53(Al) and MIL-53(Al)-TDC had comparatively rigid frameworks. Adsorption analysis revealed remarkably high adsorption capacities for PCMX on MIL-53(Al) and 2,6-DMP on MIL-53(Al)-TDC. The adsorption process followed pseudo-second-order kinetics, indicating that host-guest interactions may be responsible for the high adsorption capacity. The conventional Langmuir and the Freundlich isotherms did not describe the adsorption behavior due to the sigmoidal nature of the adsorption profiles. The sigmoidal adsorption behavior is consistent with multiple host–guest interactions, as supported by PXRD, FTIR, XPS, and DFT analyses. Temperature-dependent adsorption analysis revealed a predominantly exothermic adsorption process, with 4-CPh exhibiting more stable adsorption than PCMX and 2,6-DMP due to stronger hydrogen-bonding interactions. This work highlights the importance of framework functionality and structural adaptability in designing efficient MOF adsorbents for the removal of phenolic pollutants.
Uranium (U) contamination poses serious environmental risks, but phytoremediation efficiency is often limited. This study evaluated single and combined inoculation of two U-tolerant plant growth-promoting rhizobacteria (PGPR) strains (Microvirga sp. M2 and Bacillus cereus B6) on Sorghum sudanense for U phytoremediation under pot and field conditions. The combined inoculation (M2 +B6) showed the highest efficiency, increasing U accumulation in roots and shoots by 49.0% and 78.2%, respectively, under 100 mg·kg−1 U stress. PGPR inoculation significantly reduced malondialdehyde (MDA) content, elevated antioxidant enzyme activities and glutathione (GSH) levels, thereby alleviating oxidative damage. It is worth noting that inoculation was associated with elevated rhizosphere enzyme activities (urease, phosphatase, saccharase, and fluorescein diacetate hydrolase) and shifts in bacterial community composition (dominated by Proteobacteria, Actinobacteriota, and Gemmatimonadota). RDA revealed potential associations among acid phosphatase, catalase, urease, microbial communities, nutrient cycling, and plant U accumulation, although these findings remain correlative. Field trials offered initial evidence for the consortium's practical applicability. Collectively, this study demonstrates that the M2 + B6 consortium synergistically and effectively enhances uranium phytoremediation by promoting plant growth, fortifying antioxidant defense, and modulating the rhizosphere microbial community. Its efficacy validated in field trials highlights the consortium's great potential as a sustainable, ready-to-use inoculant for in‑situ remediation of uranium- contaminated soil, and opens promising avenues for future mechanistic exploration and wider application.
Aqueous film-forming foams (AFFF) are extensively used in firefighting and are composed of a mixture of per- and polyfluoroalkyl substances (PFAS), including anionic, cationic, and zwitterionic compounds. Remediating soils contaminated by these emerging compounds is challenging due to their distinctive behavior in soil. This study investigates soil flushing methods using sodium dodecylbenzene sulfonate (SDBS) solutions at various levels of its critical micelle concentration (CMC) and foam (90% air, 10% SDBS) to extract PFAS from AFFF-contaminated soil. Batch desorption experiments showed that increasing SDBS concentration enhanced PFAS recovery through micellar solubilization. 1D-column experiments showed that foam injection improved PFAS recovery compared to SDBS, because of the mobile air-water interface (AWI). Foam sped up desorption kinetics for short-chain anionic PFAS and caused higher concentration overshoot for long-chain anionics as more CF2 groups were present, as well as for non-anionic species, due to electrostatic and hydrophobic interactions at the AWI. Overall, foam injections achieved higher recovery rates: 100% for anionic, 90% for zwitterionic, and 66% for cationic PFAS.
Per- and polyfluoroalkyl substances (PFAS), including perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorobutanesulfonic acid (PFBS), are a critical class of emerging environmental contaminants. The continuous release of PFAS from land surfaces into water creates contaminated sites where appropriate treatment methods are needed. There are currently around 42,000 suspected industrial and municipal PFAS-contaminated sites in the United States. To evaluate sediment capping as a potential remedy in these locations, we examined the fate and transport of long- and short-chain PFAS including PFOA, PFOS, and PFBS in laboratory-scale microcosms of sediment caps using activated carbon (AC), biochar (BC), Fluorosorb® (FS200®), and sand. Pore water sampling with peepers was used to determine concentration profiles in the microcosms at three times across a 2-month period. We found that all three chemicals were contained effectively by adsorbent layers over the duration of the experiments but were able to break through the sand and reach the top surface of the beds within two months. A sediment capping model, CAPSIM, was used to interpret PFAS fate and transport in the experiments by fitting isotherm data. The modeling approach has potential applications for design and decision support at PFAS-contaminated sites. The results of this study validated contaminant transport predictions by identifying the roles of linear and nonlinear sorption equilibrium and diffusion-dispersion processes in sediment, sand, and adsorbent media.
Gyms are widely regarded as health-promoting microenvironments with intense human activity and abundant synthetic materials, yet the burden of emerging contaminants in these spaces remains poorly understood. Here, we report high concentrations of microplastics (MPs) and associated polymer additives in the indoor air of typical gyms, including plasticizers (phthalate esters, PAEs), antioxidants (p-phenylenediamines, PPDs), and their quinone derivatives (PPD-Qs). Median concentrations of PPDs/PPD-Qs (503 pg/m3), MPs (2069 ng/m3), and particle-phase PAEs (2163 ng/m3) in gym PM2.5 were one to two orders of magnitude higher than outdoor levels, while PAEs showed pronounced accumulation in the gas phase, indicating that both particle-bound and gaseous fractions should be considered. Gym aerosols exhibited a distinct chemical fingerprint enriched in parent PPDs, suggesting possible contributions from rubber-associated additives in indoor synthetic materials. Exposure assessment further revealed that younger groups showed higher body-weight-normalized intake under the modeled exposure scenarios, with MPs contributing the largest intake among the target contaminant classes. These findings identify gyms as underrecognized exercise-related indoor microenvironments for potential co-exposure to plastic- and rubber-derived contaminants, supporting future monitoring, exposure assessment, and low-emission material design in sports environments.
The present study investigated the occurrence of per- and polyfluoroalkyl substances (PFAS) and trace elements in glyphosate-based herbicides (GBHs). A set of 12 GBHs was analyzed for 68 PFAS and 12 trace elements. PFAS analysis was performed using ultra-high-performance liquid chromatography coupled with Q Exactive high-resolution orbitrap mass spectrometry (UHPLC-HRMS) whereas analysis of trace elements was performed using inductively coupled plasma mass spectrometry (ICP-MS). As a result, all investigated GBHs contained at least one PFAS and at least 10 out of the 12 trace elements. Total PFAS concentrations ranged from 216 to 3124 ng/kg product, with N-MeFOSAA being the most prevalent and abundant. Total elemental concentrations ranged from 680 to 196,752 µg/kg product, with Fe, Ti, Cu, Zn, and As among the most abundant elements. The annual Σ68PFAS inputs to Québec soils may reach 2–25 g/yr (1–16 µg/ha/yr) while global inputs may reach 809–10,986 g/yr (1–17 µg/ha/yr). The Σ12 trace elements inputs were substantially higher, reaching 14–1503 kg/yr (9–940 mg/ha/yr) in Québec and up to 657,188 kg/yr globally (9–1017 mg/ha/yr). These findings suggest additional environmental and health implications associated with contaminants other than glyphosate in GBHs, warranting further ecotoxicological and exposure assessment studies.
This study tested microwave (MW) regeneration of PFAS-laden field-spent GACs collected from four U.S. treatment plants with different operational histories. This work provides new insights into the application-specific performance and challenges of MW regeneration for exhausted, aged GAC, accounting for changes in surface chemistry, porosity, and PFAS adsorption capacity before and after MW treatment. MW treatment significantly increased the surface area (8–34%) and pore volume (7–34%) of spent GACs to levels comparable to those of virgin F400 GAC, showing improved PFAS adsorption capacity. Batch adsorption tests showed an 85–100% increase in PFAS removal efficiency after MW regeneration, comparable to virgin F400. Results from batch tests and RSSCTs consistently demonstrated the effectiveness of MW regeneration in recovering the PFAS adsorption performance of GAC. PFAS extraction results showed that PFAS concentrations decreased from 39 to 670 ng/g (field-spent GACs) to below method detection limits after MW-regeneration, indicating an extensive reduction in extractable PFAS concentrations and the accumulation of fluoride following regeneration. This accumulation demonstrated substantial PFAS defluorination, which was further enhanced by increased GAC moisture content. Overall, the findings showed the effectiveness of MW treatment in removing PFAS from field-spent GACs and in regenerating GACs.
Gen-X was introduced as safer alternative to PFOA. Although its short-chain structure reduces bioaccumulation potential, it may mimic some legacy PFAS toxic effects. Its mobility in freshwater ecosystems and persistence raise concerns about biota. This study investigates whether sub-chronic Gen-X exposure induces oxidative stress in hepatopancreas and gills of Procambarus clarkii, maintained for 28 days at three environmentally relevant Gen-X concentrations (0.5, 1, 10 µg/L), plus a control tank. Chemical analyses (pooled samples) revealed dose-dependent accumulation in tissues, mainly in hepatopancreas. Oxidative biomarkers indicated cellular damage, including lipid peroxidation in the hepatopancreas at 1 µg/L and protein and lipid oxidation in both organs at 10 µg/L. Enzymatic assays (N = 10) revealed tissue-specific responses. In the hepatopancreas, SODs activity was inhibited at the two highest doses, suggesting enzyme impairment, while it was activated in gills. In both organs, Se-GPxs exhibited a biphasic response, with increase at low exposure and decrease at high, coinciding with macromolecular injury. Catalase was inhibited at 0.5 µg/L in hepatopancreas and activated at 1 µg/L in gills, indicating compartment-specific detoxification. Results demonstrate that Gen-X disrupts redox homeostasis in P. clarkii through differential antioxidant modulation, with enzyme inhibition marking critical thresholds beyond which defences fail and oxidative damage occurs.
In this study, a novel dual-molecule system made of spiropyran-loaded magnetite is designed and synthesized in the laboratory for the degradation of Bisphenol A. Comprehensive chemical, morphological, structural, photo-responsive, and cytotoxic examinations show that the smart material has been successfully functionalized and acts as a highly active catalyst. Spiropyran-loaded magnetite nanoparticles demonstrate efficient singlet oxygen generation (approx. 59 µM of ¹O₂ in only 60 min) while maintaining sustainable operational parameters, offering a promising alternative to conventional advanced oxidation process-based systems. At a catalyst loading of 1 g/L, all photodegradation reactions followed pseudo-first-order kinetics, with apparent rate constants (k) in the range of 0.0078–0.1549 ± 0.0007 min⁻¹ (R2 > 0.989). Moreover, the photocatalyst was successfully used in four consecutive runs, without significant loss of catalytic activity. In agreement with photocatalytic oxidation data, the cytotoxicity results showed that during the photocatalytic reaction, the samples were less cytotoxic. Based on the obtained results, among the organic molecules used as photosensitizers, spiropyrans hold great promise for the development of smart photocatalysts.
Per- and polyfluoroalkyl substances (PFAS) are a diverse class of persistent, synthetic chemicals widely used in modern society, now recognised for their global distribution and adverse impacts on environmental and human health. Their pervasive presence has necessitated structured regulatory and management responses to limit exposure and mitigate risk. This review synthesises contemporary evidence on the extent of PFAS contamination across Australian environments, drawing on data from freshwater, marine, and terrestrial systems. It also examines the evolution of Australia’s PFAS policy landscape, including national regulations, environmental guidelines, monitoring programs, and frameworks governing risk assessment, management, and remediation. While substantial progress has been made, serious gaps remain in Australia’s approach to PFAS, particularly in relation to next-generation PFAS chemicals. Notably, ultra-short chain PFAS remain underrepresented in both research and regulatory frameworks, underscoring urgent need for improved monitoring, analytical methodology, and assessment of these compounds.
This study evaluated the sorption of seven per- and polyfluoroalkyl substances (PFAS) across four synthetic soil horizons representative of biosolids-impacted soils in Maine. The experimental soil profiles comprised four distinct layers (Depth 1-4) with varying compositions, where Depth 1 represented organic-rich surface soils and Depth 4 was the mineral layer characterized by higher sand and clay contents. This design enabled controlled investigation of depth-dependent PFAS sorption. Sorption kinetics for PFAS were fit by the pseudo-second-order model (R2 = 0.96-0.99), where PFOS exhibiting slower sorption than PFOA. In terms of sorption capacity, qe decreased from 2.08 to 1.54 & micro;g g-1 for PFOS and from 0.67 to 0.52 & micro;g g-1 for PFOA from surface to deeper soils, respectively. PFOS exhibited the highest sorption capacity at Depth 1 (qmax=28.17 & micro;g/g) while 90% less capacity of 2.10 & micro;g/g at Depth 4. Across all depths, long-chain PFAS exhibited higher sorption capacities (qe=0.52-2.5 & micro;g/ g) than short-chain compounds (qe=0.001-0.74 & micro;g/g). Overall, PFAS sorption increased with organic matter, PFAS chain length, indicating organic-rich surface soils acting as primary sinks espcially for long-chain PFAS, while mineral-dominated subsoils exhibited limited sorption capacity. These findings can enable vertical transport models where the mobility of short-chain PFAS and the depth-sensitive sorption behavior of long-chain analogues are crucial.
As the most widely used MXene, Ti3C2 shows immense industrial and biomedical potential. However, its expansive application leads to inevitable environmental release, raising urgent biosafety and ecological concerns. The poorly understood mechanisms of its interaction with the innate immune system currently hinder comprehensive environmental health risk assessments. This study elucidates the mechanisms underlying Ti3C2 MXene-induced immunotoxicity and pro-inflammatory activation in RAW 264.7 macrophages. Our findings suggest that the pro-inflammatory response is a sequential biological cascade closely associated with clathrinmediated endocytosis. Upon internalization, Ti3C2 MXene appears to engage a robust, parallel activation state characterized by simultaneous activation of the MAPK, PI3K/Akt, and NF-kappa B pathways. This signaling transition coincides with a profound transcriptional shift, including the upregulation of putative regulators such as Mmp9, Ccl5, and Ehfr. These genes are proposed to function as sensory amplifiers and feedback mediators that may contribute to the stabilization of a classical M1 polarized phenotype. Our findings provide a comprehensive molecular blueprint of MXene-induced activation in RAW 264.7 macrophages, offering critical insights into the biocompatibility of 2D nanomaterials and establishing a framework for risk intervention and environmental safety management.
Pervasive and recalcitrant per-and polyfluoroalkyl substances (PFAS) contamination has motivated development of a plethora of treatment approaches aimed at their degradation, with increased interest in process intensification to enhance defluorination. However, limited attention has been given to the unintended consequences of the empirical intensification of tunable electrochemical treatment systems. Here, we consider the reductive defluorination of 4-(trifluoromethyl)hexafluoropent-2-enoic acid (PFMeUPA), a lesser studied PFAS with growing health concerns, using elemental palladium (Pd(0))-coated carbon fiber paper cathodes. Pd(0) catalyzed the formation of surface-adsorbed atomic hydrogen (H center dot), which was confirmed as the reactive species responsible for defluorination via scavenger experiments with 2,4 dichlorophenol. Fluoride release (serving as direct evidence of defluorination) followed a volcano-shaped relationship with applied current, revealing an optimal operating point at-2.5 mA where defluorination was maximized. At higher currents, substantial H2 bubble formation indicated wasteful H center dot recombination and dominance of the competing hydrogen evolution reaction (HER). These results represent a caveat that increasing energy input for process intensification may eventually hinder PFAS degradation. Thus, process design and operation should not overlook HER to optimize H center dot utilization for energy-efficient PFAS defluorination.
