Fireworks production leads to severe perchlorate contamination in aquatic systems, yet traditional approaches struggle to resolve the spatially coupled industrial pollution dynamics and governance fragmentation in river basins, fundamentally limiting effective perchlorate mitigation. Herein, we investigate the spatiotemporal patterns of perchlorate contamination in China's largest fireworks production regions, observing a significant ″accumulation corridor″ aligning with the industrial clustering zones. We developed a knowledge-guided framework, integrating process-based hydrology with deep learning, to predict perchlorate concentration dynamics at the basin scale. The model outperforms traditional data-driven approaches in capturing long-term trends and episodic peaks while leveraging Mixture-of-Experts (MoE) gates to distinguish point versus nonpoint sources. We demonstrate that industrial point sources contribute ∼65% of total corridor loads, whereas nonpoint loads are seasonally amplified, with rainy-season fluxes 1.7-2.8× higher than dry seasons. Attention analysis identifies that average fireworks factory density, precipitation, and soil properties are dominant drivers for nonpoint perchlorate sources. Furthermore, multiscenario simulations indicate that coordinated controls on point, nonpoint, and upstream boundary inputs substantially reduce exceedance frequency within the simulated ensembles. This work provides a transferable framework that converts fragmented observations into basin-scale diagnosis and scenario-based decision support for industrial contaminant risks, contingent on local monitoring, industrial structure information, and regulatory setting.

The pervasive contamination of groundwater by highly toxic oxyanions necessitates advanced sensing technologies capable of high-throughput screening. To overcome the intrinsic single-analyte limitation of conventional ion-selective electrodes (ISEs), we developed a biomimetic sensor array inspired by the cross-reactive principles of biological taste systems, which was constructed by self-assembling quaternary ammonium salts (QACs) with tailored alkyl chain lengths (Cn) within MXene interlayers (MXene/QAC-Cn). When integrated with a machine learning model, the array successfully enabled the simultaneous identification of four kinds of oxyanions (CrO42-, SeO42-, BrO3-, and ClO4-) with a discrimination accuracy of 97.1%. The sensor demonstrated exceptional sensitivity, achieving a detection limit of 1.2 × 10-9 M, and a 32-fold enhancement in analytical throughput compared to single-analyte approaches. Theoretical calculations revealed that the confined microenvironment of the MXene/QAC-Cn composite promotes partial dehydration of the oxyanions, reducing the adsorption energy by 1.09 eV. This mechanism is pivotal for generating high-quality and differentiable response fingerprints, which in turn ensures the high accuracy of the machine learning model. The programmable design of this platform underscores its potential for extension to a broader spectrum of oxyanions, offering a versatile and scalable solution for comprehensive water quality monitoring.

Aggregation of long-chain quaternary ammonium compounds (LC-QACs) into aggregates (e.g., micelles) during material modification often limits their grafting efficiency in porous adsorbents like powdered activated carbon (PAC), thereby constraining performance in anionic pollutant removal. Herein, we report a supramolecular strategy that employs beta-cyclodextrin (beta-CD) to suppress CTAB aggregation, enabling monomeric diffusion and enhanced CTAB loading within PAC micropores. The resulting beta-CD/CTAB-PAC composite achieves a high perchlorate (ClO4-) adsorption capacity of 211 mg g(-1), significantly surpassing the conventional CTAB-modified PAC (87 mg g(-1)), along with remarkable selectivity (distribution coefficient > 10 & times; higher than competing anions), stability (<8% leaching in 10-day immersion), and regenerability (>91% capacity retention over 6 cycles). Fixed-bed column tests validated its practical efficacy, treating >5400 bed volumes of contaminated water (500 mu g L-1) to below the drinking standard of 70 mu g L-1. Furthermore, density functional theory calculations attribute the high selectivity to the low hydration energy of ClO4-. Its sparse hydration shell results in a lower energy penalty for desolvation, enabling a more direct and stronger electrostatic interaction with the quaternary ammonium sites compared to the heavily hydrated competing anions. Overall, this aggregation-suppression approach provides a generalizable route for optimizing LC-QAC-based functionalization of porous materials.

Harmful algal blooms (HABs) threaten drinking water safety and ecosystem stability. Pre-oxidation-coagulation is an effective control method, but its operational optimization remains challenging due to nonlinear parameter interactions and limited systematic datasets. A machine learning-based inverse design framework was developed to optimize pre-oxidation-coagulation processes for algal removal. Literature data (n = 328) were supplemented with 471 newly conducted orthogonal experiments, yielding a balanced dataset (n = 799) covering nine oxidants, three coagulants, and pre-oxidation times from 5 to 60 min. A stacked ensemble model, employing Cat-Boost as the meta-learner over four base algorithms, was trained and interpreted using SHAP analysis. The model was coupled with sequential quadratic programming (SQP) for inverse parameter optimization, with target removal efficiency of 90 %. The ensemble model achieved an average test R2 = 0.783, with substantial gains for challenging oxidants such as K2FeO4 (+34.01 %). SHAP analysis ranked parameter importance as coagulant dose > oxidant dose > pre-oxidation time > oxidant type, revealing saturation of pre-oxidation effects within 5-20 min. Inverse design reduced experimental workload by over 98 % (384-6 validation runs) while maintaining +/- 8.34 % accuracy. Experimental validation (6 triplicate runs) confirmed both predictive reliability and process efficiency. Balanced datasets are critical for capturing oxidation-specific dynamics. The proposed framework offers a cost-effective, data-driven solution for rapid, precise HAB control, bridging laboratory studies with fullscale water treatment operations.

Ultrashort-chain PFAS like trifluoroacetate (TFA) evade conventional detection due to high hydrophilicity and redox inertness, demanding field-deployable sensors with molecular-level specificity. Herein, we engineer a heterostructured UiO-66-F4/MIP@Ti3C2Tx sensor leveraging triple synergy, where UiO-66-F4 exploits F center dot center dot center dot F interactions for TFA enrichment, molecularly imprinted polymers (MIPs) enforce geometric exclusion of interferent, and Ti3C2Tx MXene accelerates charge transfer. Detection employs [Fe(CN)6]3-/4-signal attenuation via steric-electronic dual-barrier obstruction. The sensor achieves ultralow 6.94 ng/L TFA detection with 0.01-100 mu g/L linear range, 93.25-107.93 % recovery in environmental waters, and 4.60 % RSD stability over cycles, showing better performance than the reported sensors and comparable performance to the gold-standard GC-MS. Theoretical calculations reveal that UiO-66-F4 harnesses F center dot center dot center dot F interactions to enhance TFA adsorption energy by 3.3 kcal/mol versus UiO-66, and IGM analysis demonstrates F center dot center dot center dot F interactions become to dominate binding energy between TFA and UiO-66-F4. Overall, this study highlights the potential of our F center dot center dot center dot F boosted imprinting strategy for reliable and efficient on-site detection of TFA at trace level, advancing sustainable pollution development.

Perchlorate (ClO4-) contamination poses persistent and global risks to human health and ecosystems through drinking water and the food chain, highlighting the need for effective removal strategies. Unlike separation-based technologies, chemical and electrochemical reduction can convert ClO4- to harmless chloride (Cl-), but the kinetic inertness of ClO4- presents substantial challenges. This review summarizes recent advances in ClO4- reduction in aqueous systems, including direct reduction, catalytic reduction, and electrocatalysis. For direct reduction, Fe- and Ti-based systems are discussed, underscoring their thermodynamic favorability but severe kinetic limitations and requirements for harsh conditions. In catalytic strategies, the oxygen atom transfer (OAT) and hydrodeoxygenation mechanisms are discussed in homogeneous Re/Mo/Fe complexes and heterogeneous bimetallic catalysts, particularly Re-Pd/C and Mo-Pd/C. In addition, precious group metal (PGM)-based hydrogenation systems and photocatalytic processes are discussed. Electrocatalytic approaches are reviewed in terms of anodic corrosion-generated reductants, metal-mediated OAT at cathodes, and atomic-hydrogen-mediated reduction on PGM and non-noble surfaces. Across these systems, available kinetic rate constants for ClO4- reduction to Cl- are compiled, and the influence of ligands in catalysts, metal composition, supports, and water matrices is analyzed. The major limitations of current strategies are summarized. Finally, research priorities in rational catalyst design, reactor and process engineering, and advanced mechanistic characterization are outlined, with the aim of developing novel ClO4- reduction technologies that are faster, capable of operating under mild, environmentally relevant conditions, and suitable for practical water treatment.

Given the high energy consumption of conventional mineralization in heterogeneous advanced oxidation processes (AOPs), polymerization transfer (PT) pathway offers a sustainable alternative that enables efficient total organic carbon (TOC) abatement with the potential for polymeric products recovery from wastewater. Herein, an innovative interfacial engineering strategy was proposed using nanobubbles (NBs) to enhance the PT pathway in carbon nanotube (CNT)/peroxymonosulfate (PMS) system. We demonstrate that 81% TOC of acetaminophen is removed by NB/CNT/PMS system, which is approximately double and ten-fold higher than those by CNT/PMS and NB/PMS systems, respectively. Molecular structure analysis on CNT surface deposits reveals a substantial increase in C-C and C-O coupling polymeric products in the presence of NBs, confirming that the enhanced TOC removal is predominantly achieved via the PT pathway. Mechanistic studies identify that CNT aggregation on gas-liquid interfaces creates numerous confined microreactors, enhancing electron transfer efficiency and significantly boosting the yields of phenoxy radicals, thus steering the reaction towards polymerization. Furthermore, the NBs suppresses CNT deactivation, maintaining high catalytic activity over 50 operational periods. Overall, this work offers an efficient and sustainable strategy for enhancing AOP performance from PT pathway and advancing PT-dominated AOPs toward practical water decontamination.

Perchlorate exposure via drinking water has been extensively related to the incidence of thyroid diseases. However, escalating perchlorate contamination in drinking water sources remains underprioritized across much of the globe. Here, we report a geospatial model depicting the probability of perchlorate exceeding 70 mu g/L in natural water under diverse climates and industrial contexts, encompassing nearly 200 coun-tries/regions lacking robust monitoring data. We demonstrate that '145 million people are at risk of perchlorate exposure, with 93.6% residing in low-and middle-income countries. Upon geospatial map-ping, we reveal that '80 countries/regions are facing potential public health threats caused by perchlo-rate exposure, which is previously unreported. Furthermore, by leveraging reinforcement learning, we propose spatially differentiated control strategies to achieve maximum reduction in perchlorate-affected populations with minimal cost. These key insights will contribute to the sustainable development of perchlorate-related industries and facilitate the achievement of Sustainable Development Goal 6 (Clean Water for All).

Nitrogenous heterocyclic disinfection byproducts (NH-DBPs) are an emerging group of N-DBPs, with several species detected in treated waters and some exhibiting notable toxicity (e.g., halopyrroles, halopyridines). However, the structural diversity and reaction behaviors of other NH-DBPs remain insufficiently characterized. In this study, we investigate a series of amide heterocyclic DBPs (AH-DBPs) formed during chlorination. These compounds possess dual identities as both NH-DBPs and organic chloramines, including chloro‑cyanuric acid, chloro‑2-methyl-4-hydroxypyrimidine, chloro‑uracil, chloro‑6-methyluracil, chloro‑isocytosine, chloro‑5,5-dimethylhydantoin, and chloro‑hydantoin. Unlike conventional organic chloramines, these AH-DBPs exhibit higher stability in the presence of free chlorine, maintaining 45-90% residue after 24 h. These AH-DBPs exhibit three distinct kinetic behaviors based on the profiles of chlorine speciation (i.e., total chlorine, free chlorine, and organic chloramines) across environmentally relevant conditions. We further observe comparable bactericidal performance between freshly prepared chlorine and AH-DBPs, while after 48-h storing, AH-DBPs achieve 1.5-2.0 times higher log reductions against Escherichia coli than chlorine. The residues of free chlorine and AH-DBPs are 1.0 and 0.2∼0.5 mg L-1 as Cl2 after 48-h storing. This enhancement correlates with slower self-decomposition kinetics of AH-DBPs than free chlorine. Furthermore, using 1,3,5-trimethoxybenzene (TMB) as a probe, we demonstrate that AH-DBPs exhibit higher oxidative reactivity than conventional organic chloramines like chloro‑n-propylamine. Theoretical calculations quantitatively corroborate the experimental phenomenon, revealing activation energies of 17.98 (chlorine), ∼21 (AH-DBPs), and 31.39 (chloro‑n-propylamine) kcal mol-1 for TMB oxidation. These findings deepen our understanding of AH-DBPs as a class of organic chloramines exhibiting unexpected oxidative reactivity, which may influence disinfection performance in chlorinated water.

This study systematically investigates the behaviors and mechanisms of N,N-dichloramine decomposition in new iron pipes (NIP) and corroded iron pipes (CIP). The half-life of N,N-dichloramine in the CIP is orders of magnitude shorter than in the NIP (0.46 min vs. 35.5 h), accompanied by substantial formation of ammonia (0.27 mg/L as NH3-N). We demonstrate that the Fe2+-N,N-dichloramine complex formed in CIP is a critical factor in catalyzing the decay of N,N-dichloramine and promoting ammonia formation. Density functional calculations confirm that the coordination bond formed between Fe2+ and N,N-dichloramine effectively lowers the energy barrier for N,N-dichloramine decomposition via the nitrile pathway, thereby promoting ammonia formation. Furthermore, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) provides molecular-level evidence for the Fe2+-N,N-dichloramine complex-catalyzed deamination of CHNO compounds to CHO species. These findings suggest that metal-induced decomposition of organic chloramines could trigger unforeseen ammonia release, underscoring the need to account for disinfection strategies in iron-based DWDS.

The urgent need for monitoring trifluoromethanesulfonic acid (TFMS), a widespread and highly persistent member of the ultrashort-chain per- and polyfluoroalkyl substances (PFAS) family, is hampered by the formidable challenge of developing a selective and sensitive sensing platform. Herein, we address this gap through designing a nanoconfined microenvironment by intercalating 4-trifluoromethy-benzylammonium bromide into MXene (MX/CF3BZA) to construct a highly selective channel for TFMS detection. The resulting MX/CF3BZA-based ion-selective electrodes (ISEs) achieve remarkable performance, exhibiting an ultralow detection limit (1.2 × 10-11 M), which is over 1 × 104-fold lower than that of conventional commercial ISEs, 17-fold enhancement in selectivity (Kij ∼ 7 × 10-3), and near-Nernstian sensitivity of 56.37 mV/decade. Quartz crystal microbalance measurements directly corroborate this superior performance, showing a 6.4-fold stronger affinity of MX/CF3BZA for TFMS compared with pristine MXene. Density functional theory calculations reveal that the CF3BZA modification creates a unique nanoconfined environment that integrates synergistic F-F, electrostatic, and anion-π interactions, reducing the permeation energy barrier for TFMS by 16.71 kcal/mol. Furthermore, we integrated the ISE into a smartphone-based platform, demonstrating its practical application for on-site TFMS detection. This study showcases the potential of precise interface engineering in advanced sensing platforms for ultrashort-chain PFAS and beyond.

Anion exchange resins (AERs) represent an effective technology for perchlorate (ClO4-) removal from wastewater, yet conventional quaternary ammonium (QA) functionalized AERs suffer from limited selectivity towards ClO4- due to indiscriminate electrostatic interactions with competing anions. To address this limitation, six novel AERs modified with long-chain quaternary ammonium (LCQA) groups were synthesized via nucleophilic grafting. Experimental characterizations confirmed successful LCQA loading on chloromethylated polystyrene matrices. Among these, the C-14-chain optimized AER (AER-14) demonstrated high-efficiency performance, achieving an adsorption capacity of 217.7 mg g(-1), with separation factor of 47.9 against SO4-. AER-14 exhibited remarkable operational resilience, maintaining a broad pH work range (2-12) and exceptional anti-anions interference capability. Regeneration of AER-14 via a mixture eluent (0.35 M FeCl3/2 M HCl/35 % ethanol) almost restored initial capacity. In rapid small-scale column tests, AER-14 processed similar to 1235 bed volume (123.5 L) of actual firework manufacturing wastewater (similar to 50 mg L-1) before breakthrough (0.7 mg L-1), outperforming commercial strong base gel resin (717-AER) by 91 % in treatable volume. This work establishes a design strategy for selective ClO4- adsorbents, providing a feasible pathway for sustainable wastewater treatment and green transformation in ClO4--intensive industries.

The pervasive contamination of groundwater by highly toxic oxyanions necessitates advanced sensing technologies capable of high-throughput screening. To overcome the intrinsic single-analyte limitation of conventional ion-selective electrodes (ISEs), we developed a biomimetic sensor array inspired by the cross-reactive principles of biological taste systems, which was constructed by self-assembling quaternary ammonium salts (QACs) with tailored alkyl chain lengths (Cn) within MXene interlayers (MXene/QAC-Cn). When integrated with a machine learning model, the array successfully enabled the simultaneous identification of four kinds of oxyanions (CrO4 2-, SeO4 2-, BrO3 -, and ClO4 -) with a discrimination accuracy of 97.1%. The sensor demonstrated exceptional sensitivity, achieving a detection limit of 1.2 & times; 10-9 M, and a 32-fold enhancement in analytical throughput compared to single-analyte approaches. Theoretical calculations revealed that the confined microenvironment of the MXene/QAC-Cn composite promotes partial dehydration of the oxyanions, reducing the adsorption energy by 1.09 eV. This mechanism is pivotal for generating high-quality and differentiable response fingerprints, which in turn ensures the high accuracy of the machine learning model. The programmable design of this platform underscores its potential for extension to a broader spectrum of oxyanions, offering a versatile and scalable solution for comprehensive water quality monitoring.

Strategies for selective perchlorate (ClO4−) removal from industrial wastewater remain critical but insufficiently explored, as existing technologies prioritize idealized performance metrics over scalability and cost-effectiveness. Herein, a counterintuitive phenomenon is reported that specific-chain-length QACs (C12-C16) can initiate selective ClO4− co-assembly into 0.2-0.3 μm flocs starting at sub-CMC concentrations. Thus, we propose a QACs-assisted ultrafiltration (UF) process to treat ClO4− wastewater. Our experimental results show that QACs-assisted UF achieves up to ∼99% ClO4− removal for specific industrial wastewater, with only ∼10% decline in flux and resist interference from 10-fold excess competing anions. Through state-of-the-art characterizations and meticulous theoretical calculations, we reveal that ClO4− triggers interaction transition from repulsion to attraction between QACs with C12-C16 alkyl chains via synergistic van der Waals, hydrophobic, and electrostatic effects, enabling QACs−ClO4− co-assembly and spontaneous floc formation. Furthermore, we demonstrate that QACs with C12, C14, and C16 alkyl chains bind ClO4− with high Kd of 1.4 × 104, 3.4 × 104, and 7.6 × 104 M-1, and ΔG of -23.60, -25.86, and -27.86 kJ/mol, respectively. Overall, QAC-assisted UF provides a low-pressure, interference-tolerant route to achieve near-complete ClO4− removal in real industrial wastewater.

Drinking water disinfection processes are generally effective at eliminating waterborne pathogens and preventing waterborne disease outbreaks. However, some chlorine-resistant opportunistic fungal pathogens have still been detected in drinking water in recent years, suggesting that conventional chlorination may be less effective against certain fungi. In this study, a chlorine-resistant strain of Aspergillus terreus was isolated from finished water in Changsha, Hunan Province, China. Upon exposure to 2 mg/L free chlorine for 30 min, the isolated strain exhibited markedly higher survival (< 0.84-log inactivation) than the standard reference strain (> 2.33-log inactivation). Metabolomic analysis revealed that chlorine resistance was associated with stress-induced metabolic reprogramming, involving key pathways such as unsaturated fatty acid biosynthesis; cutin, suberin, and wax biosynthesis; and the citrate cycle. The resistant strain upregulated specific metabolites, including citrate and oleic acid, which are typically involved in maintaining cellular vital activities and reinforcing cell membrane integrity. Based on the aforementioned mechanism, we evaluated monochloramine as an alternative disinfectant for A. terreus. Monochloramine exhibited superior membrane-penetrating ability, achieving a 2.05-log inactivation at CT 60 mg·min/L compared with free chlorine under the same conditions, which achieved a 0.84-log inactivation. This study highlights the potential limitations of conventional chlorination and proposes a strategy for controlling chlorine-resistant fungi in drinking water.

Perchlorate (ClO4⁻) is a persistent and toxic oxyanion widely used in military and industrial activities, posing a crucial challenge in drinking water treatment due to its high solubility and chemical stability. To meet increasingly stringent regulatory limits, adsorbents suitable for full-scale treatment must reconcile high selectivity, rapid kinetics and material safety. Herein, we develop a modified granular activated carbon (GAC) using poly(diallyldimethylammonium chloride) (PDDA), a cationic polyelectrolyte widely used in water-treatment processes. The PDDA-GAC exhibits high ClO4⁻ selectivity against common competing anions and rapid adsorption kinetics, reaching saturation within 10 min. The remarkable performance is attributed to a unique surface-confined functionalization. The enhanced surface hydrophobicity (water contact angle: 71.2°) favors the enrichment of weakly hydrated ClO4⁻, which is then rapidly captured via strong electrostatic interaction (∼70 kcal mol-1) with readily accessible quaternary ammonium groups, minimizing intraparticle diffusion resistance. In fixed-bed treatment of source water containing 500 μg L-1 ClO4⁻, PDDA-GAC increases the treatable volume before breakthrough at 70 μg L-1 from 950 to 3250 bed volumes, compared to pristine GAC, and maintains excellent reusability. Overall, this work provides an efficient, rapid, and safe adsorbent platform with strong potential for full-scale ClO4⁻ removal.

Selective perchlorate (ClO4 -) removal from surface water is a pressing need due to the stringent perchlo-rate drinking water limits around the world. Herein, we anchored N+ -C-H hydrogen bond donors in hydrophobic cavities via interactions of cationic surfactants with montmorillonite to prioritize perchlo-rate bonding. The prepared adsorbent exhibited high selectivity over commonly occurring competing anions, including SO4 2-, NO3 -, PO4 3-, HCO3 -, and halide anions. High adsorption capacity, fast adsorption kinetics, and excellent regeneration ability (removal efficiency >= 80% after 20 cycles) were confirmed via batch experiments. Unconventional CH O hydrogen bonding was verified as the primary driving force for perchlorate adsorption, which relies on the higher bond energy (similar to 80 kcal mol-1 ) than conventional bonding. The removal efficiency of anions followed the order of the Hofmeister Series, demonstrating the importance of hydrophobic cavities formed by the tail groups of cationic surfactants. The hydropho-bic cavities sheltered the C-H bonds from interacting with anions of low hydration energy (e.g., perchlo-rate). Furthermore, a fixed-bed column test demonstrated that about 2900 bed volumes of the feeding streams (similar to 500 lg L-1 ) can be treated to <= 70 lg L-1 , with an enrichment factor of 10.3. Overall, on the basis of the hydrophobicity-induced hydrogen bonding mechanism, a series of low-cost adsorbents canbe synthesized and applied for specific perchlorate removal. (c) 2025 THE AUTHORS. Published by Elsevier LTD on behalf of Chinese Academy of Engineering and Higher Education Press Limited Company. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Perchlorate (ClO 4 − ) contamination in surface water is an escalating issue for drinking water safety. Herein, an imine‐linked covalent organic framework (COF) tuned by quaternary ammonium alkyls (R 4 N + ) is developed for ClO 4 − adsorption. The hydrophobic and cationic COF adsorbent achieves a record‐breaking adsorption capacity of ClO 4 − at 912.7 mg g −1 , demonstrating remarkable selectivity for ClO 4 − over other environmentally relevant anions and exhibiting rapid adsorption kinetics. Furthermore, the adsorbent maintains excellent recycling performance (removal efficiency ≥ 80% after 10 cycles) using tetrachloroferrate for regeneration. In dynamic flow‐through experiments with real water samples, the adsorbent effectively treats ≈3200‐bed volumes of feed streams (≈500 µg L −1 ), with an enrichment factor of 15.2. The hydrophobicity of the COF adsorbent is identified as a premise for its interaction with ClO 4 − . Molecular dynamic simulations and density functional theory calculations reveal that R 4 N + anchored in COF cores enriches ClO 4 − via electrostatic attraction and bonds with ClO 4 − via unconventional hydrogen bonds (C─H─O). These key insights pave the way for future design and optimization of adsorbents for removing oxo‐anion from water, especially for ClO 4 − .

Ozone water, which is known for its effective disinfection properties and low cytotoxicity, represents a significant method for treating dental caries. S. mutans, a major cariogenic bacterium, was selected as the research subject, and a point-of-use BDD device was utilized to produce low-concentration ozone water through anode electrolysis. This research demonstrated that ozone water effectively inactivates free-living and biofilm-forming bacteria, with the latter showing increased resistance correlated with elevated EPS secretion, which provides protective benefits. Additionally, an artificial mouth model was established to simulate the growth of S. mutans biofilms in the human mouth, where the biofilm received twice daily ozone water treatments over several days. The results indicated that ozone water effectively eliminated S. mutans biofilms, with higher concentrations and longer treatment periods enhancing its efficacy. This study revealed that ozone water not only oxidizes EPS to reduce cellular resistance and disrupt biofilm structure but also damages the cell membrane, resulting in content leakage, decreased ATP levels, and eventual cell inactivation, thereby facilitating biofilm removal. These findings support the feasibility of the use of ozone water to treat dental caries, as demonstrated by experiments involving the eradication of biofilms in the artificial mouth model.