Boron carbide (B4C) has high active electrons due to its density of state localization, so it can be used as an active site to activate CO2 molecules. At the same...

Coagulation,as a core process in water and wastewater treatment,plays a vital role in the sustainable utilization of water resources.However,traditional inorganic aluminum/iron salt coagulants face limitations in practical applications,such as slow floc growth,small floc size that is difficult to settle,and high residual metal ion concentrations.These issues not only increase operational costs but also reduce process adaptability,making it difficult to meet the national low-carbon development requirements.In recent years,titanium salt coagulants have attracted significant attention due to their unique hydrolysis characteristics,excellent settling performance,and low residual metal concentrations.They have become a research hotspot in the field of water treatment.This paper systematically reviews the century-long development of titanium salt coagulants,with a focus on analyzing the floc characteristics,deep purification efficiency,and process adaptability of a new type of titanium xerogel coagulant(TXC)obtained via the sol-gel method.Furthermore,this paper provides a forward-looking perspective on the challenges faced in innovative material design,mechanism research,and engineering application of titanium-based coagulation technology.

The photocatalytic degradation of antibiotics is effective but may yield transformation products (TPs) that sustain or amplify ecological risks, including antibiotic resistance gene (ARG) induction. This study developed a predictive framework that couples photocatalytic experiments, high-resolution mass spectrometry, density functional theory (DFT) calculations and machine learning (ML) to assess risks of TPs. Using tetracycline as a model compound, we constructed a reaction network over 120 steps and 9 533 reactions, and trained an ML model to rapidly predict Gibbs free energy changes with DFT accuracy. Automatic transition-state searches were integrated to evaluate kinetic accessibility within the network. The generalizability of this approach was validated with pathways of five different antibiotics involving 545 reactions. Furthermore, a multi-dimensional scoring system was developed that integrates diversity, ecotoxicity, biodegradability, and feasibility (DEBF) to prioritize pathways by both reactivity and sustainability. Several hydroxylated, aminated, and amide-ketone TPs were identified as high-risk species with enhanced ARG-binding potential. By bridging molecular energetics with ecological outcomes, this work offers a generalizable, mechanism-anchored, and risk-aware approach for analyzing photocatalytic transformations and deriving design principles for pollutant degradation that balance efficiency with ecological safety.

In this paper, the positive and negative charges in the silicon carbide catalyst are separated by mechanical force to produce piezoelectric effect. Under the action of piezoelectric effect, the positive and negative charges formed on the surface of silicon carbide further react with carbon dioxide and intermediate species, which drives the reduction reaction of carbon dioxide. Through design experiments and density functional theory calculations, the "on-off" effect of piezoelectric effect in carbon dioxide reduction reaction and the catalytic reaction mechanism are clarified. The results show that the piezoelectric effect makes the electrons transfer from the C atom of the active site of silicon carbide to the C-C bond formed with the adsorbed carbon dioxide, and at the same time, the electrons on the C=O bond in carbon dioxide transfer to the O atom, which promotes the adsorption and activation of CO2 molecules. Piezoelectric action changed the electron transport path of the intermediate species *COOH, successfully activated *COOH, weakened the C-O bond and increased the electron density on the O atom, making it easier for H+ to attack the O atom and then generate the key intermediate species *CO. Without piezoelectric action, this step could not happen, so the piezoelectric effect played a "switch" role. In addition, the C-C coupling in the reaction is not the traditional C-C coupling between *CO, but through the (*CHO+*CO→ *CHOCO) path, and then through a series of catalytic hydrogenation reactions, the reduction of carbon dioxide to methanol and ethanol is realized at room temperature.

In the process of synthesizing hydrogen peroxide from water and oxygen at room temperature, the reaction of water or its hydrogen ions with either oxygen or superoxide radicals is thermodynamically unfavorable (ΔGθ > 0) and also has a high activation energy. This significantly limits the progress of the reaction and the manifestation of its activity. To solve this problem, this paper found through density functional theory simulation budget that the frictional catalysis of amorphous strontium barium titanooxalate can activate the proton alcohol solvent, so that it can release highly active hydrogen protons that react preferentially with oxygen, and the alcohol that loses hydrogen protons can be combined with hydrogen protons in aqueous solution to "recover", thus acting as a hydrogen proton "transfer station" to cycle out highly active proton hydrogen. This highly active protonic hydrogen readily combines with oxygen to form hydrogen peroxide. Therefore, the tribocatalytic effect of amorphous strontium barium titanooxalate can overcome the thermodynamic prohibitions and high activation energy that limit the reaction between water and oxygen, thereby efficiently synthesizing hydrogen peroxide. Corresponding experimental results also prove this budget result.

Confinement has been extensively studied in catalysis over recent decades. Although it shapes active sites across enzymatic, supramolecular, and heterogeneous systems, research remains predominantly focused on solid materials. To advance the field, we propose a water-centric framework for classifying confined systems, elevating water from a passive solvent to an active architectural element that defines unique catalytic landscapes. This paradigm shift is essential for distinguishing genuine confinement effects—arising from nanoscale water structuring—from phenomena such as local concentration enrichment or surface interactions. By centering water’s role, this framework enables the design of next-generation catalysts capable of breaking traditional scaling relations for sustainable energy production and environmental remediation. Key challenges include defining critical spatial and interfacial thresholds, exploiting curvature-driven electric fields, and leveraging synergies between different confinement types.

Microbial contamination and enzymatic browning remain key challenges in apple juice processing. This study introduces ultraviolet-activated diacetyl (UV/BD) as a non-thermal intervention that simultaneously ensures microbial safety and quality retention. Treatment with 0.5 mM BD and 1.5 kJ/m2 UV reduced native bacterial counts below detection limits and suppressed browning by 32.9% through two synergistic mechanisms: photolytically generated peroxyacetyl radicals selectively oxidize polyphenol oxidase, while oxygen-deprivation resulting from BD photooxidation halts quinone formation and starves peroxidase by inhibiting H2O2 generation. The primary BD photolysis product, acetic acid, ensures no harmful residues and no off-flavors detected at the applied concentration. Comprehensive acute and subacute murine toxicity studies confirmed clinical safety, with no mortality, hematological deviations, or histopathological alterations observed. This technology offers immediate scalability via existing UV infrastructure, bridging the critical gap between safety, quality, and sustainability in juice processing.

The reduction of hexavalent chromium (Cr(VI)) under alkaline conditions remains significant challenge. In this study, we deigned a simple reaction system to generate reductive radicals, which enabled the complete reduction of Cr(VI) under alkaline conditions. The total Cr was easily removed due to the formation of Cr(III) precipitates, exhibiting excellent recyclability. Alcohols were introduced in the thermal activated persulfate (PS) system, and the reaction between oxidative radicals and alcohols resulted in the generation of alcohol radicals. Electron paramagnetic resonance (EPR) measurement, free radical quenching experiments, and chemical probe trapping all demonstrated that alcohol radicals were responsible for the efficient reduction of Cr(VI). Adding different alcohol precursors enabled the generation of corresponding alcohol radicals, which all achieved high efficiency in Cr(VI) reduction and Cr removal, and the Cr slag contained 39.6 % Cr. The detection of acetic acid (ethanol radical oxidation product) indicated that oxygen atom transfer (OAT) mechanism was predominated in the Cr (VI) reduction process by alcohols radicals. Furthermore, density functional theory (DFT) calculations also revealed that OAT process required lower activation energy and generated more thermodynamically stable products. This study provides a new insight on the reduction of Cr(VI) at high pH, and a promising strategy for the treatment of Cr(VI)-contaminated wastewater, ensuring both environmental and economic benefits.

Heavy metal complex wastewater, characterized by “three complexities and one stability” (diverse sources, multiple types, varied ionic forms, and stable coordination structures), poses significant challenges in industrial pollution control. While these wastewaters are laden with strategic metals like copper, nickel, and chromium, making them a critical resource, their treatment is hampered by high cost, low efficiency, excessive sludge generation, and difficulties in recovering valuable metals. The key to unlocking this resource potential lies in decomplexation, i.e., the breaking of stable metal-ligand bonds. Current resource-oriented strategies for this purpose could be categorized into five groups: sole oxidation, sole reduction, oxidation-reduction synergy, displacement, and displacement-redox synergy, each operating through distinct mechanisms for decomplexation and subsequent metal recovery. This review systematically summarizes recent advances in these technologies, analyzes their mechanisms and efficiencies, and identifies current limitations. Looking forward, we propose that the future of this field hinges on leveraging geochemical principles to drive selective decomplexation and integrating artificial intelligence (AI)-driven high-throughput screening, molecular design, and biomimetic targeting to develop precision agents. By establishing a geochemistry- and AI-based framework, this review aims to steer heavy metal wastewater treatment toward greener, smarter, and closed-loop resource recovery paradigms, offering innovative insights for sustainable pollution control and resource security.

The management and control of harmful cyanobacterial blooms remain a persistent global environmental challenge. This study evaluated the algicidal efficacy and ecological impacts of butanedione (BD), a naturally occurring agent, in aquatic microcosms that simulate real-world conditions. Special attention was given to the distinct roles of its two main photolytic products, peroxyacetyl radical (CH3C(O)OO•) and acetate (Ac). The results demonstrated that Ac exerted minimal short-term impact on cyanobacterial proliferation. In contrast, BD-derived radicals induced rapid cyanobacterial suppression, improving key water quality parameters in the early phase and subsequently supporting the recovery of eukaryotic algae. These radicals also markedly altered aquatic community structure, enriched beneficial photoheterotrophic bacteria, and suppressed functional pathways related to cell envelope biosynthesis. Notably, BD treatment reduced the abundance of antibiotic resistance genes (ARGs) and virulence factor genes, as well as the total relative abundance of potential bacterial hosts carrying both types of genes to 1/5 of that observed in the Ac-treated group. These results underscore BD's dual functionality as an effective cyanocide with application potential, providing a scientifically grounded strategy for the sustainable management of harmful cyanobacteria-affected aquatic ecosystems.

Environmental chemistry, a cornerstone of environmental science, faces critical challenges including research homogenization, the persistent gap between laboratory-scale discoveries and engineering-scale applications, and the need to rationally integrate emerging data-driven tools. Drawing on deliberations from the 6th Youth Forum on Frontiers of Environmental Science and Engineering, this perspective outlines three guiding principles for the discipline’s future. First, fundamental mechanistic research—particularly on interfacial reaction kinetics, radical pathways, and molecular recognition—must be strengthened to provide interpretable physicochemical bases for cross-disciplinary innovations. Second, engineering thinking should be embedded from the outset, incorporating life-cycle assessment and real-water-matrix complexities to bridge the “last mile” between high-performance materials and practical deployment. Third, artificial intelligence (AI) should be positioned as an auxiliary tool rather than a universal solution; its pattern-recognition capabilities can accelerate hypothesis generation and process optimization, but its outputs require mechanistic validation and causality scrutiny. Ultimately, the authors advocate a closed-loop paradigm of “hypothesis–prediction–validation” that integrates empirical research, AI-assisted analytics, and collaborative academia–industry–government platforms, ensuring that environmental chemistry evolves from homogenized competition toward original breakthroughs and tangible environmental benefits.

In 2025, PFAS treatment approaches moved beyond separation and/or destruction to complete mineralization and potential resource recovery.

As tribocatalysis gains increasing attention for the efficient degradation of refractory organic pollutants, developing facile synthesis strategies to boost tribocatalytic performance has become a key research focus. In this work, anatase-rich TiO2 nanoparticles with high crystallinity were prepared via a hydrothermal method, and both the morphology and crystal phase were systematically tuned by varying the hydrothermal temperature. The optimal sample, obtained at 150 oC, possessed a large specific surface area of 121.69 m2/g and a high pore volume of 0.41 cm3/g. Under magnetic stirring with a Teflon rotating disk at 400 rpm in the dark at room temperature, 50 mg of this sample completely degraded 50 mL of a 20 mg/L Rhodamine B (RhB) solution within 5 h, achieving 100% degradation efficiency, and still retained 96% efficiency after five consecutive cycles. Weak adsorption of RhB onto the TiO2 nanoparticles was confirmed, ruling out any dominant contribution from surface adsorption. Electron paramagnetic resonance (EPR) spectroscopy and active-species trapping experiments revealed that friction-generated holes (h⁺) are the primary reactive species, with electrons (e⁻) and hydroxyl radicals (·OH) also participating in the degradation process. These results demonstrate that hydrothermally synthesized TiO2 nanoparticles constitute a cost-effective, high-performance, and environmentally benign tribocatalyst, and they provide a rational strategy for designing advanced tribocatalytic materials for environmental remediation.

Humic acid (HA) is ubiquitous in water and significantly influences coagulation performance of metal salts. To guide the rational selection of coagulants, this study systematically investigates the interactions between HA functional groups and the hydrolyzed species of three metal salt coagulants: titanium xerogel coagulant (TXC), polyferric sulfate (PFS), and polyaluminium chloride (PAC). Their distinct binding behaviors were elucidated by leveraging two spectroscopic techniques: Fourier transform infrared and three-dimensional fluorescence spectroscopy. The resulting spectra were subsequently analyzed using two-dimensional correlation analysis (2D-COS) to resolve binding sequences and fluorescence regional integration (FRI) to quantify changes in humic acid fractions. The results demonstrate that TXC coordinated effectively with phenolic hydroxyl, carboxyl, and vinyl groups, demonstrating robust sweep flocculation under acidic conditions that was further enhanced in neutral/alkaline environments. PFS showed similar complexation but weaker sweep flocculation, while PAC failed to form effective flocs in acidic condition. In neutral/alkaline conditions, PFS and PAC primarily targeted carboxyl groups through adsorption-bridging and charge neutralization. The coagulation efficiency was ultimately determined by the distribution of hydrolyzed species and their specific interactions with HA, providing a theoretical basis for coagulant selection and optimization under varying water quality conditions.

Peroxidase‐mimicking nanozymes have revolutionized biomedicine and environmental catalysis, but their pH‐dependent catalytic behavior remains a blind spot in activity evaluation and application design. Here, a framework is presented for understanding and harnessing pH effects through a synergistic interplay of interfacial electrostatics and proton‐coupled electron transfer (PCET) process. Contrary to the entrenched “pH 4.0 gold standard,” the proposed multi‐index evaluation matrix for activity evaluation reveals that platinum nanozymes achieve peak activity at pH <2.5 via proton‐triggered surface reconstruction and optimized PCET energetics. This insight enables a pH‐adaptive bio‐ and contaminant‐sensing strategy: by leveraging the signals of the double‐electron oxidation product of 3,3′,5,5′‐tetramethylbenzidine (TMB 2 ⁺) at pH 2.5, a 47‐fold increase in glutathione determination sensitivity is achieved over the traditional single‐electron oxidation product (TMB⁺ • ) analysis at pH 4.0. This study not only recalibrates nanozyme evaluation benchmarks but also pioneers proton‐engineered catalysis for environmental applications.

Nanozymes, while possessing greater stability and durability than their natural counterparts, still face limitations of low catalytic activity and inefficient production. Here, we report a one-step method for the efficient construction of highly active nanozymes. The photolysis of butanedione was leveraged to generate surface-functionalized metal nanozymes. The in situ generated surface acetate (Ac) ligands serve as electron bridges between the substrates to boost the electron transfer, thus drastically improving the catalytic activity. The resulting Ac-Ptzyme, with a precisely tuned surface Ac content, demonstrated a peroxidase-like activity superior to that of the natural horseradish peroxidase and was approximately 200 times greater than that of Fe3O4. This superior activity endowed the Ac-Ptzyme with enhanced performance for visually monitoring the oxidative stress in bloom-forming cyanobacterial cells and for killing pathogenic bacteria in biofilm. This work paves a path to the facile synthesis of high-activity nanozymes for catalysis.

The paper clarifies the two electron transfer mechanism of water splitting of TiB2 under tribocatalysis. The results of the paper show that under the action of multifunctional TiB2, taking advantage of the characteristics of tribocatalysis, it not only solves the problem of hydrogen evolution selectivity in pure water splitting, but also avoids the limitation of hydrogen peroxide on the reaction rate, and finally greatly improves the efficiency of water splitting hydrogen evolution reaction. In the paper, TiB2 exhibits four excellent functions under the action of friction. The four functions of TiB2 are: First, the surface of TiB2 can continuously generate a large number of positive and negative charges by tribocatalysis. Second, it can efficiently catalyze the water splitting reaction. Third, it is extremely easy to catalyze water splitting and positive charges to form hydroxyl radicals and oxygen to form superoxide radicals. Final, it is very easy to decompose the intermediate hydrogen peroxide. TiB2 provides sufficient electrons for water splitting hydrogen evolution reaction through tribocatalysis, and simultaneously decomposes hydrogen peroxide to break the speed control step. It improves the reaction rate and avoids the poisoning effect of hydrogen peroxide. The positive charge reacts with water to release a large amount of hydrogen ions, which become the hydrogen ion source for the hydrogen evolution reaction. The oxygen liberated by hydrogen peroxide is further catalytically converted to form superoxide radicals, which greatly promotes the forward progress of the water splitting reaction.

Mass-independent isotope fractionation (MIF) enables powerful geochemical tracers for various geological and planetary problems, yet the mechanisms driving MIF for tin (Sn) remain ambiguous. Here, we demonstrate that distinct Sn isotope fractionation signatures were produced during photolysis of organic Sn species (i.e., methyltin) under laboratory UV irradiation and natural sunlight. UV irradiation of methyltin induced pronounced Sn-MIF in all odd Sn isotopes (Δ115Sn up to 21.82‰, Δ117Sn up to 23.16‰, Δ119Sn up to 24.01‰), with their ratios (Δ117Sn/Δ115Sn = 1.069; Δ119Sn/Δ115Sn = 1.099; Δ119Sn/Δ117Sn = 1.028) strongly correlating with nuclear magnetic moments. This unambiguously identifies the magnetic isotope effect (MIE) as the driving mechanism, ruling out other causes such as the nuclear volume effect (NVE). Methyl radicals (•CH3) were detectable during the methyltin photolysis experiments, and the magnitude of MIF for Sn was suppressed by the presence of electron spin trapping agent (DMPO) for radicals, supporting that the pronounced Sn-MIF originated from radical-mediated singlet-triplet state transitions of Sn species. Furthermore, the magnitude of Sn-MIF depended nonmonotonically on external magnetic fields (peak suppression at 100 to 180 G), implying competition between hyperfine coupling and Zeeman interactions. Notably, Sn-MIF was absent during photolysis of methyltin by natural sunlight despite significant mass-dependent Sn isotope fractionation (e.g., >3‰ in δ122/116Sn), attributed to atmospheric ozone shielding of short-wavelength UV (<290 nm) required for radical generation. Our results register Sn-MIF as a sensitive tracer of UV-driven photochemistry in low-oxygen environments, underlining the potential of Sn isotopes in studies of early Earth's atmosphere and planetary environments.

At ambient conditions, boron nitride (BN) is incapable of catalyzing the liquid-phase synthesis of hydrogen peroxide from oxygen and water. However, experiments have demonstrated that friction can significantly enhance the efficiency of this reaction. Under certain experimental conditions, the yield of hydrogen peroxide reached 8374.58 mu mol/L/g. This study utilizes density functional theory (DFT) and associated experimental calculations to investigate the mechanism by which oxygen is reduced in water to form hydrogen peroxide. The application of frictional force enables the continuous generation of a substantial amount of hydrogen ions and superoxide radicals, thus facilitating the reaction. The process primarily proceeds through two pathways: O2 -> center dot O2 - -> center dot OOH -> H2O2 and O2 + 2q- + 2H+ -> H2O2.