Deyou Yu

Rational design of regenerants for perfluoroalkyl and polyfluoroalkyl substances (PFAS)-laden ion-exchange resins is hindered by the complex interplay among solution components, resin properties, and PFAS structures. This study applied machine learning (ML) with 916 experimental data points to predict the liquid-phase desorption efficiency (DE) of PFAS-laden resins and identify critical influencing factors. We observed that DE positively correlated with the application of polyacrylic resins and organic solvent concentration, but was negatively influenced by PFAS chain length. Subsequently, the interpretable ML model was employed to design targeted regeneration strategies, guiding a systematic assessment from single-component to multicomponent regenerants. The model revealed that polyacrylic resins achieve high DE (>95%) using single-chloride salts (e.g., 5–10% NaCl) through ion exchange. In contrast, most polystyrene resins require combined alkali-salt solutions to surpass 80% DE by disrupting hydrophobic interactions. Model-proposed optimal formulations for nine resins across four PFAS were experimentally validated, demonstrating a close match between predictions and outcomes with a mean absolute deviation of 10.5–16.7 percentage points. This study offers a transferable and data-driven strategy for optimizing resin regenerant formulations, highlighting interpretable ML’s role in advancing efficient recovery practices.

Mass transfer limitations and inefficient nonradical oxidant generation often constrain the practical performance of Fenton-like catalysts for micropollutant removal. Here, we develop a synergistic architectural strategy to construct carbon-supported cobalt single-atom catalysts (Co-INC) via ammonium iodide-assisted chemical vapor deposition, integrating atomically dispersed Co–N4 sites with carbon–iodine (C–I) coordination motifs to simultaneously enhance reactant transport and singlet oxygen (1O2) production. Benefiting from in situ NH3-mediated etching, the architecture enhances active-site accessibility while achieving a high Co density of 0.165 mmol g–1, facilitating peroxymonosulfate (PMS) diffusion. Additionally, iodine incorporation creates an asymmetric Co–N4/C–I coordination environment that upshifts Co d-band center to −0.54 eV, strengthening PMS adsorption (−2.54 eV). This configuration promotes interfacial electron transfer and reduces the rate-determining energy barrier to −0.84 eV, substantially boosting 1O2 generation and achieving a steady-state concentration of 0.295 mM. Furthermore, the optimized pore architecture alleviates mass-transfer constraints, enabling efficient 1O2 utilization and a 2.3-fold increase in the ciprofloxacin mass-transfer coefficient. Consequently, Co-INC exhibits an exceptional normalized rate constant of 507 min–1·M–1 for ciprofloxacin degradation, outperforming pristine Co-NC by 10.3 times and surpassing most PMS-based catalysts. This study demonstrates that coupling active-site coordination with mass-transfer enhancement is pivotal for maximizing nonradical oxidation pathways in water treatment.

In this study, we introduce a highly effective non-metallic iodine single-atom catalyst (SAC), referred to as I-NC, which is strategically confined within a nitrogen-doped carbon (NC) scaffold. This configuration features a distinctive C-I coordination that optimizes the electronic structure of the nitrogen-adjacent carbon sites. As a result, this arrangement enhances electron transfer from peroxymonosulfate (PMS) to the active sites, particularly the electron-deficient carbon. This electron transfer is followed by a deprotonation process that generates the peroxymonosulfate radical (SO₅^•−). Subsequently, the SO₅^•− radical undergoes a disproportionation reaction, leading to the production of singlet oxygen (¹O₂). Furthermore, the energy barrier for the rate-limiting step of SO₅^•− generation in I-NC is significantly lower at 1.45 eV, compared to 1.65 eV in the NC scaffold. This reduction in energy barrier effectively overcomes kinetic obstacles, thereby facilitating an enhanced generation of ¹O₂. Consequently, the I-NC catalyst exhibits remarkable catalytic efficiency and unmatched reactivity for PMS activation. This leads to a significantly accelerated degradation of pollutants, evidenced by a relatively high observed kinetic rate constant (k_obs ~ 0.436 min⁻¹) compared to other metallic SACs. This study offers valuable insights into the rational design of effective non-metallic SACs, showcasing their promising potential for Fenton-like reactions in water treatment applications.

As regulatory standards for per- and polyfluoroalkyl substances (PFAS) become increasingly stringent, innovative water treatment technologies are urgently demanded for effective PFAS removal. Reported sorbents often exhibit limited affinity for PFAS and are frequently hindered by competitive background substances. Recently, fluorinated sorbents (abbreviated as fluorosorbents) have emerged as a potent solution by leveraging fluorine-fluorine (F···F) interactions to enhance selectivity and efficiency in PFAS removal. This review delves into the designs and applications of fluorosorbents, emphasizing how F···F interactions improve PFAS binding affinity. Specifically, the existence of F···F interactions results in removal efficiencies orders of magnitude higher than other counterpart sorbents, particularly under competitive conditions. Furthermore, we provide a detailed analysis of the fundamental principles underlying F···F interactions and elucidate their synergistic effects with other sorption forces, which contribute to the enhanced efficacy and selectivity. Subsequently, we examine various fluorosorbents and their synthesis and fluorination techniques, underscore the importance of accurately characterizing F···F interactions through advanced analytical methods, and emphasize the significance of this interaction in developing selective sorbents. Finally, we discuss challenges and opportunities associated with employing advanced techniques to guide the design of selective sorbents and advocate for further research in the development of sustainable and cost-effective treatment technologies leveraging F···F interactions.

Electronic structure modulation of active sites is critical important in Fenton catalysis as it offers a promising strategy for boosting H₂O₂ activation. However, efficient generation of hydroxyl radicals (•OH) is often limited to the unoptimized coordination environment of active sites. Herein, we report the rational design and synthesis of iron oxyfluoride (FeOF), whose iron sites strongly coordinate with the most electronegative fluorine atoms in a characteristic moiety of F-(Fe(III)O₃)-F, for effective H₂O₂ activation with potent •OH generation. Results demonstrate that the fluorine coordination plays a pivotal role in lowering the local electron density and optimizing the electronic structures of iron sites, thus facilitating the rate-limiting H₂O₂ adsorption and subsequent peroxyl bond cleavage reactions. Consequently, FeOF exhibits a significant and pH-adaptive •OH yield (~450 µM) with high selectivity, which is 1 ~ 3 orders of magnitude higher than the state-of-the-art iron-based catalysts, leading to excellent degradation activities against various organic pollutants at neutral condition. This work provides fundamental insights into the function of fluorine coordination in boosting Fenton catalysis at atomic level, which may inspire the design of efficient active sites for sustainable environmental remediation.

Here, stretchable hierarchical porous polyurethane fibers were designed, fabricated, and employed as a three-dimensional hierarchical interconnected framework for conductive networks interwoven with silver nanoparticles and carbon nanotubes. The fiber possessed favorable thermal insulation, strain sensing, and electric heating properties. The core-shell layered porous structure of fiber made the fiber have high heat insulation performance (the difference value of temperature |ΔT| = 3.54, 8.9, and 12.7 °C at heating stage temperatures of 35, 50, and 65 °C) and ultrahigh elongation at break (813%). Importantly, after conductive filler decoration, the fiber could exhibit real-time strain-sensing capacities with a high gauge factor. In addition, the fibers could be heated at low voltage, like an electrical heater. The development of flexible, stretchable, and multifunctional porous fibers had great potential applications in intelligent wearable devices for integrated thermal management, strain sensing, and intrinsic self-warming capability.

Detergency determination for single polymeric fibers is of significant importance to screening effective detergents for laundry, but remains challenging. Herein, we demonstrate a novel and effective method to quantify the detergency for single polymeric fibers using a confocal laser scanning microscope (CLSM). It was applied to visualize the oil-removing process of single polymeric fibers and thus assess the detergency of various detergents. Four typical surfactants were selected for comparison, and a compounded detergent containing multiple components (e.g., anionic and nonionic surfactants, enzymes) was demonstrated to be the most effective and powerful soil-removing detergent because more than 50% of oil on the cotton fiber could be easily removed. Moreover, the oil removal process of three kinds of fibers (i.e., cotton, viscose, and polyester) was imaged and monitored by confocal microscopy. It was found that the percentage of the detergency of a single polyester fiber exceeded 70%, which is much higher than that of cotton and viscose fibers (~50%), which may be due to its relatively smooth surface. Compared to traditional methods, the CLSM imaging method is more feasible and effective to determine the detergency of detergents for single polymeric fibers.