Wanyi Fu

Dissolution–reprecipitation enables durable pollutant immobilization via mineral transformation, distinct from adsorption or coprecipitation.

Heterogeneous catalytic degradation of per- and polyfluoroalkyl substances (PFAS) through cleavage of the strong C-F bonds offers a robust and sustainable approach for mitigating their global threat to ecosystems and human health. However, current reduction or oxidation methods generally achieve only partial degradation of PFAS, producing chain-shortened intermediates that are often more recalcitrant and thus resulting in limited defluorination efficiency. In this study, we developed a nanoconfined photocatalytic system by encapsulating MIL-125-NH₂(Ti) within a graphene aerogel (GA) matrix. Mechanistic investigations reveal that the MIL-125-NH₂(Ti)/GA composite could generate both reductive hydrated electrons (e_aq^–) and oxidative hydroxyl radicals (HO^•) under UV irradiation, enabling integrated cascade reduction-oxidation reactions in a single system. Interestingly, the nanoconfinement effect of GA improves the adsorption affinity towards PFAS with various chain lengths by more than 30% and lowers the C-F bond energy by a maximum of 10.8%. These kinetic and thermodynamic advantages collectively resulted in high defluorination ratios, i.e., 90.2% for perfluorooctanoic acid (PFOA), 65.3% for perfluorohexanoic acid (PFHxA), and 51.8% for perfluorobutanoic acid (PFBA) within 12 h, which are typically unattainable in conventional heterogeneous catalytic systems. Our findings open avenues for advanced heterogeneous systems to address the global PFAS challenge.

Conventional catalytic water purification remains energy‐ and chemical‐intensive due to reliance on external stimuli for oxidant activation. Here, we present a self‐sustaining catalytic membrane (TMF‐CM) incorporating Ti‐doped Mn ₃ O ₄ /Fe ₃ O ₄ catalysts with engineered oxygen vacancies, which harness pollutants as electron donors to drive enzyme‐mimetic redox cycles. Through nanoconfinement within ceramic membrane pores, dissolved oxygen is autonomously activated by electrons derived from contaminants, enabling continuous regeneration of active sites without chemical additives. Mechanistic investigations, supported by spectroscopic and computational evidence, reveal that high‐valent metal–oxo intermediates mediate contaminant oxidation while concurrently restoring oxygen vacancies, thereby sustaining catalytic cycles. During 10‐day continuous testing in real wastewater, the TMF‐CM system achieved over 90.1% contaminant removal and exhibited self‐cleaning capability. This autonomous catalytic paradigm leverages the inherent chemical energy of wastewater, eliminating chemical additives and cutting energy consumption by 70%–98% compared to UV‐ or electrochemical‐based systems. By integrating molecular oxygen activation with circular electron transfer, we establish a sustainable oxidation strategy that extends beyond conventional water treatment paradigms.

Conventional catalytic water purification remains energy‐ and chemical‐intensive due to reliance on external stimuli for oxidant activation. Here, we present a self‐sustaining catalytic membrane (TMF‐CM) incorporating Ti‐doped Mn ₃ O ₄ /Fe ₃ O ₄ catalysts with engineered oxygen vacancies, which harness pollutants as electron donors to drive enzyme‐mimetic redox cycles. Through nanoconfinement within ceramic membrane pores, dissolved oxygen is autonomously activated by electrons derived from contaminants, enabling continuous regeneration of active sites without chemical additives. Mechanistic investigations, supported by spectroscopic and computational evidence, reveal that high‐valent metal–oxo intermediates mediate contaminant oxidation while concurrently restoring oxygen vacancies, thereby sustaining catalytic cycles. During 10‐day continuous testing in real wastewater, the TMF‐CM system achieved over 90.1% contaminant removal and exhibited self‐cleaning capability. This autonomous catalytic paradigm leverages the inherent chemical energy of wastewater, eliminating chemical additives and cutting energy consumption by 70%–98% compared to UV‐ or electrochemical‐based systems. By integrating molecular oxygen activation with circular electron transfer, we establish a sustainable oxidation strategy that extends beyond conventional water treatment paradigms.

Selective transformation of phenol in wastewater into value-added products offers a sustainable strategy for simultaneous pollutant abatement and chemical resource recovery. However, conventional oxidation processes suffer from low product selectivity due to competing pathways, including ring-opening degradation, C-C/C-O coupling, and polymerization. Here, we develop an angstrom-confined flow-through system using laminar membrane nanochannels to enable spatiotemporally controlled oxidation and regioselective C-C coupling. The 6.0 Å interlayer spacing of ZnFe-layered double hydroxide enforces stereoselective alignment of phenoxy radicals, while flow modulation precisely regulates the reaction progression. This enzyme-inspired dual-control strategy achieves 84% C-C selectivity at 50% phenol conversion and suppresses parasitic pathways (C-O coupling, overoxidation) that are endemic to traditional batch systems. Mechanistic studies and density functional theory (DFT) calculations reveal that nanoconfinement thermodynamically stabilizes para-oriented radicals, steering barrierless C-C coupling. Integrated with selective resin adsorption for biphenol harvest and phenol recycling, up to 90% cumulative product yield is achieved. This work establishes a low-carbon pollutant-to-product paradigm for resource recovery from contaminated waters.

Lanthanum-based materials are recognized as highly effective adsorbents for advanced phosphorus removal, with a prevailing belief that acidic conditions promote phosphorus uptake via enhanced surface complexation. Herein, we demonstrate that lanthanum carbonate exhibits a 1.8-fold higher phosphate adsorption capacity at pH 7 (33.2 mg-P/g) compared to pH 4 (18.5 mg-P/g), attributed to the enhanced formation of LaPO₄ nanocrystals. Leveraging in situ atomic force microscopy (AFM), we resolve real-time phosphorus sequestration dynamics, capturing LaPO₄ nucleation within minutes, contradicting prior reports that LaPO₄ formation is time-intensive. This discrepancy arises because conventional characterization techniques (e.g., X-ray diffraction) overlook transient amorphous LaPO₄ intermediates due to insufficient sensitivity, whereas the nanoscale resolution of AFM directly tracks interfacial transformations. A dissolution-nucleation-growth mechanism was then proposed for the interfacial formation of LaPO₄. This study revises the mechanistic framework for phosphorus removal and highlights the crucial role of LaPO₄ formation in maximizing the utilization efficiency of lanthanum active sites for enhanced phosphate sequestration by La-based materials.

Nanotechnology-enabled water treatment is the most attractive approach to realizing advanced purification of contaminated waters that challenge the efficacy of traditional water treatment technologies. Confining nanomaterials inside porous scaffolds or substrates is one of the most effective strategies to push nano-enabled water treatment technologies forward from laboratory to field application. As flourishingly reported, confinement effects induce significantly improved decontamination efficiency, such as enhanced adsorption capacity, reaction kinetics, stability, and selectivity. In this review, first we provide an overview of the general fundamentals of nanoconfinement effects and their implications in environmental remediation. Next, we review confined Fe-based nanomaterials, such as different polymorphs of iron-oxides, oxyhydroxides, zero-valent iron, and single-atom iron as representative materials towards their applications in nanoconfinement systems for water decontamination. Finally, we propose future studies based on the missing scientific fundamentals regarding nanoconfinement effects and challenges for translating unique and promising nanoconfinement observations to engineering applications of confined nanomaterials-driven water treatment technologies.

Pyrogenic carbons (PCs), with varying structures depending on the materials and thermal treatment conditions, have been extensively used to enhance anaerobic digestion by mediating electron transfer. However, the underlying mechanism has yet to be explored. Herein, the redirection and enhancement of the direct interspecies electron transfer (DIET) pathway were evidenced, along with the upregulated electrochemical properties and structural proteins in the methanogenic consortia. Further, we found that PCs featured trade-off properties of "biopseudocapacitor" and "bioconductor" during thermal treatment, as endowed by the evolution of oxygen-containing functional groups (for charging and discharging) and graphitic structure (for conductivity). Correspondingly, their trade-off effect on mediating syntrophic methanogenesis (SM) was realized between the generally acknowledged bioconductor role and the pseudocapacitive effect, as highlighted by the enhanced SM of reduced PCs from more balanced electron exchange capacities. Consequently, a performance comparison of PCs obtained at 450, 650, and 850 °C in SM resulted in an optimized sample at 650 °C, where a 61.3 ± 1.8% increase in methane production rate and a 33.4 ± 1.1% decrease in lag time were observed. Microbiologically, DIET-active Methanothrix and Geobacteraceae flourished with the intra- and extracellular electron transport channels established. These findings provide new insights into the mediating mechanism and renewable potential of PCs in regulating energy-harvesting biochemical processes toward carbon neutrality.