Meiping Tong

Insufficient oxygen mass transfer and inadequate charge separation are two critical factors restricting the photocatalytic efficiency of covalent organic frameworks (COFs) for water purification. Here, we develop a facile strategy to simultaneously boost oxygen mass transfer and charge separation in COFs through constructing efficient oxygen capture tentacles via replacing conventional pyridine groups with nicotinic‐acid/methyl‐nicotinate groups, which have tunable oxygen affinity. Molecular dynamics simulations and in situ characterizations reveal that compared to pyridine groups in COF‐EP1 and nicotinic‐acid groups in COF‐EP2, respectively serving as weak and medium oxygen capture tentacles, methyl‐nicotinate groups in COF‐EP3 can serve as strong oxygen capture tentacles due to their superb oxygen affinity, which can enhance oxygen interaction energies and thus promote oxygen mass transfer. Owing to the optimal charge polarization, methyl‐nicotinate groups in COF‐EP3 also strengthen internal electric fields to facilitate charge separation. COF‐EP3 thus achieves exceptional photocatalytic degradation performance towards sulfadiazine (99.5% removal in 25 min, k = 0.21 min ⁻¹ ), which is 16.2 and 2.8 times higher than that of COF‐EP1 ( k = 0.013 min ⁻¹ ) and COF‐EP2 ( k = 0.076 min ⁻¹ ), respectively. Besides, COF‐EP3 exhibits high sulfadiazine degradation performance in complicated water matrices, continuous‐flow system, and scaled‐up reactor, demonstrating its practical application potential.

Insufficient oxygen mass transfer and inadequate charge separation are two critical factors restricting the photocatalytic efficiency of covalent organic frameworks (COFs) for water purification. Here, we develop a facile strategy to simultaneously boost oxygen mass transfer and charge separation in COFs through constructing efficient oxygen capture tentacles via replacing conventional pyridine groups with nicotinic‐acid/methyl‐nicotinate groups, which have tunable oxygen affinity. Molecular dynamics simulations and in situ characterizations reveal that compared to pyridine groups in COF‐EP1 and nicotinic‐acid groups in COF‐EP2, respectively serving as weak and medium oxygen capture tentacles, methyl‐nicotinate groups in COF‐EP3 can serve as strong oxygen capture tentacles due to their superb oxygen affinity, which can enhance oxygen interaction energies and thus promote oxygen mass transfer. Owing to the optimal charge polarization, methyl‐nicotinate groups in COF‐EP3 also strengthen internal electric fields to facilitate charge separation. COF‐EP3 thus achieves exceptional photocatalytic degradation performance towards sulfadiazine (99.5% removal in 25 min, k = 0.21 min ⁻¹ ), which is 16.2 and 2.8 times higher than that of COF‐EP1 ( k = 0.013 min ⁻¹ ) and COF‐EP2 ( k = 0.076 min ⁻¹ ), respectively. Besides, COF‐EP3 exhibits high sulfadiazine degradation performance in complicated water matrices, continuous‐flow system, and scaled‐up reactor, demonstrating its practical application potential.

Wastewater treatment plants simultaneously emit greenhouse gases and rely on external carbon sources, presenting both a challenge and an opportunity for carbon circularity. We develop a comprehensive life-cycle assessment of 32 Waste-to-Chemical pathways that integrate thermochemical and electrochemical conversions in sequential or parallel architectures to convert CH₄ and CO₂ into reusable carbon sources for in-plant utilization. Sequential thermochemical-electrochemical coupling consistently delivers the strongest climate benefit, with formate identified as the optimal product, reducing emissions up to ~35% reduction relative to direct-emission baselines. We further validate this pathway experimentally using commercially available Pd/Al₂O₃ catalysts for CH₄ thermochemical oxidation and Bi₂O₃ catalysts for CO₂ electroreduction in a porous solid electrolyte reactor. Residual heat generated during CH₄ oxidation enhances downstream CO₂ electroreduction, enabling 97.2 ± 1.2% Faradaic efficiency toward separation-free formate at 150 mA cm⁻² and 45 °C. These results validate that commercially relevant catalysts and thermally coupled operation can deliver experimentally validated performance aligned with system-level projections. This framework establishes a scalable strategy for embedding carbon circularity into wastewater infrastructure and transforming wastewater treatment plants into distributed platforms for low-carbon chemical production.

Ice-phase Cr(VI) reduction is commonly attributed to freeze concentration and proton enrichment, implicitly assuming solution-like reaction mechanisms. However, this study reveals that interfacial processes serve as a critical complement to freeze concentration and strongly influence reaction pathways in ways not explained by concentration enrichment alone. By investigating nine structurally diverse organic acids under frozen conditions and comparing them with aqueous systems, we observed no reduction at ambient temperature but pronounced, structure-dependent behaviors in frozen solution. Organic acids were categorized into three classes: Class I (e.g., tartaric acid) promoted Cr(VI) reduction in the dark via five-membered ring complexes and showed light enhancement correlated with TD-DFT excitation energies (R2 = 0.93), consistent with photoinduced ligand-to-metal charge transfer (LMCT). Class II (maleic acid) reduced Cr(VI) only under visible light through a dehydration-hydration-chromate ester pathway. Strikingly, Class III acids (e.g., acetic acid) suppressed reduction, likely by competitively adsorbing on ice surfaces, disrupting proton mobility and blocking catalytic sites, as supported by CP2K/DFT calculations. These findings underscore that freeze concentration alone is insufficient to explain pathway selection and that interfacial processes make an essential contribution by modulating coordination environments and proton-coupled electron transfer in frozen systems. This work redefines frozen-phase reactivity, highlighting the imperative of interfacial processes in predicting contaminant transformations in cold environments.

Freeze–thaw (FT) cycle, a ubiquitous and important physical process in natural environments, may influence the horizontal gene transfer (HGT) process of antibiotic-resistant genes (ARGs), yet its impact and underlying mechanisms remain unclear. This study investigated the impact and mechanisms of FT cycles on ARG conjugative transfer among intra- and interspecies under different solution ionic strength conditions. The results showed that despite ionic strengths and species pairs, different FT treatment cycles induced diverse influences on ARG conjugation frequency with inhibition effect of 1 FT cycle (decreased by 3.5–76-fold) and facilitation effect of 2 and 3 FT cycles (promoted by 2–27-fold). The reduced conjugation frequency after 1 FT treatment cycle is mainly attributed to energy deficiency caused by the starvation process during FT treatment. The enhanced cell–cell adhesion induced by the increased hydrophobicity and secretion of bacterial extracellular polymeric substances (EPS) facilitated the formation of conjugative pilus, primarily promoting the ARG conjugative transfer process after 2 and 3 FT treatment cycles. The results of our study clearly show that FT cycles (intensified by the ongoing climate change) exhibit profound influence on the dissemination of ARGs, which helps understand and predict ARG risks in different natural environments.

Hydrogen peroxide (H ₂ O ₂ ) photosynthesis from H ₂ O and O ₂ using covalent organic frameworks (COFs) is a sustainable approach, yet its efficiency is restricted by a sluggish water oxidation reaction (WOR) due to insufficient water adsorption and charge separation. Herein, we propose a facile and universal polar center spatial‐manipulation strategy to enable efficient H ₂ O ₂ photosynthesis by COFs via converting high‐polarity C═N linkages into 4‐carboxyl‐quinolyl linkages with weakened‐polarity quinoline backbones and ultra‐polar carboxyl side chains (forming COF‐TBC). This polar‐center side‐shifting strategy concurrently enhances water adsorption (via the polar carboxyl side chain) and water activation (enabled by efficient exciton formation and separation along the low‐polarity quinoline backbone) by COF‐TBC, lowering the energy barrier of the rate‐determining WOR and achieving outstanding and stable H ₂ O ₂ photosynthesis from O ₂ and H ₂ O without sacrificial agents (5624 µmol g ⁻¹ h ⁻¹ , accumulating to 41 mM, solar‐to‐chemical efficiency of 0.72%). The polar‐center side‐shifting strategy can be extended to modify other COFs for enhancing H ₂ O ₂ photosynthesis, indicating its universality. COF‐TBC maintains high H ₂ O ₂ yield in complex real‐water matrices and can be integrated into membrane‐based and continuous‐flow reactors for successive H ₂ O ₂ generation under natural sunlight. COF‐TBC also exhibits efficient photocatalytic performance toward organic contaminant degradation and microorganism inactivation, highlighting its broad potential for water purification.

Hydrogen peroxide (H ₂ O ₂ ) photosynthesis from H ₂ O and O ₂ using covalent organic frameworks (COFs) is a sustainable approach, yet its efficiency is restricted by a sluggish water oxidation reaction (WOR) due to insufficient water adsorption and charge separation. Herein, we propose a facile and universal polar center spatial‐manipulation strategy to enable efficient H ₂ O ₂ photosynthesis by COFs via converting high‐polarity C═N linkages into 4‐carboxyl‐quinolyl linkages with weakened‐polarity quinoline backbones and ultra‐polar carboxyl side chains (forming COF‐TBC). This polar‐center side‐shifting strategy concurrently enhances water adsorption (via the polar carboxyl side chain) and water activation (enabled by efficient exciton formation and separation along the low‐polarity quinoline backbone) by COF‐TBC, lowering the energy barrier of the rate‐determining WOR and achieving outstanding and stable H ₂ O ₂ photosynthesis from O ₂ and H ₂ O without sacrificial agents (5624 µmol g ⁻¹ h ⁻¹ , accumulating to 41 mM, solar‐to‐chemical efficiency of 0.72%). The polar‐center side‐shifting strategy can be extended to modify other COFs for enhancing H ₂ O ₂ photosynthesis, indicating its universality. COF‐TBC maintains high H ₂ O ₂ yield in complex real‐water matrices and can be integrated into membrane‐based and continuous‐flow reactors for successive H ₂ O ₂ generation under natural sunlight. COF‐TBC also exhibits efficient photocatalytic performance toward organic contaminant degradation and microorganism inactivation, highlighting its broad potential for water purification.

The abuse of antibiotics leads to widespread antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in water systems, threatening public health. Existing disinfection technologies have limitations including the generation of toxic disinfection byproducts (DBPs) and inefficiency in eliminating intracellular ARGs. Herein, we provide an effective and toxic-DBP-free disinfection approach to remove ARB/ARGs by reactive species generated via activation of sodium percarbonate (SPC) inside and outside cells with naturally abundant sunlight. Combining in situ characterization and theoretical calculation, we reveal that CO₃^•-, ^•OH, and O₂^•- are generated both intra- and extracellularly. SPC passively diffusing into cells complexes with intracellular substances (e.g., heme, Fe-S cluster protein, and cytochrome c) to produce various reactive species in situ under sunlight irradiation, leading to the locally increased oxidation levels within cells. These reactive species synergistically contribute to the collapse of the antioxidant system, resulting in effective ARB inactivation and ARGs degradation. Owing to its limited reactivity toward background substances in water and effective intracellular oxidation mechanisms, the SPC/sunlight system demonstrates efficient ARB disinfection capabilities without any toxic DBPs generation in real water. This study presents a green, cost-effective, and toxic-DBP-free alternative for efficient ARB/ARGs removal with deep insights into intracellular oxidation mechanisms.