The efficient development and clean utilization of biomass energy have garnered increasing attention, with potential solutions being proposed to alleviate global pressures on energy and chemical demands. In this work, a degradation system of Caragana korshinskii (Ck) with formic acid (FA) as an additive was constructed, and combinations of FA with five solvents, including cyclohexane, ethyl acetate, methanol, ethanol, and isopropanol, were compared. Among them, FA and ethanol exhibit a positive synergistic effect in Ck degradation. As a proton-type nucleophilic reagent, ethanol can effectively swell Ck by providing a supercritical environment, penetrating into the dense macromolecular skeleton, and participating in alkylation, alkyl/alkoxy transfer, and transesterification. In addition, FA provides H+ and in-situ hydrogen, promoting cleavage > C-O- bonds and stabilizing active fragments. Density functional theory calculation results also support the proposed FA-ethanol synergistic effect, because H+-assisted phenethoxybenzene cleavage pathways of FA-ethanolysis have lower energy barriers than those of conventional ethanolysis. Results show that FA-alcoholysis increases both oil yield and O content. Under optimal conditions (2 g Ck, 16 mL ethanol, 4 mL FA, 300 °C, and 60 min), bio-oil yields increased from 17.8 wt% for conventional ethanolysis to 49.6 wt% for FA-ethanolysis. By comparing the composition differences among three bio-oils derived from FA-alcoholysis, it was found that abundant aliphatic Cal-O/C=O and arenes/Car-O species can be obtained from FA-methanolysis/ethanolysis and FA-isopropanolysis, respectively. Overall, the combination of FA and ethanol is more favorable than other tested systems.

Polyethylene terephthalate (PET) has broad environmental applications, yet its inherent poor conductivity limits its utility in microbial fuel cell (MFC). This study addressed the need for cost-effective and conductive PET-supported materials. In this study, PET-supported three-dimensional materials were used as a substrate, introducing the conductive coating layer that enhanced hydrophilicity, electrochemically active surface area, and decreased charge transfer resistance. The PET-supported cathode modified with polypyrrole (PPy) and carbon nanotubes (CNTs) achieved a maximal power density (758.2 mW/m2) with long-term operational stability for 4 months. The PET/PPy/CNTs cathode exhibited 2.23-fold higher nitrate removal efficiency than carbon felt cathode. Notably, the average viability of biofilm on the internal surface of PET/PPy/CNTs (63.5%) was 2.89-fold higher than carbon felt. Furthermore, the PET/PPy/CNTs demonstrated significant cost-effectiveness with a cost of approximately $2.04/m2. Considering the superior bioelectrochemical performance, low costs, and low life cycle environmental impacts, the PET-supported cathode demonstrates notable potential for enhancing MFC performance.

Surface atomic oxygen (*O) is increasingly considered a reactive oxygen species in catalytic ozonation. However, its role as a key intermediate in ozone activation remains poorly understood, while the mechanism governing its site-dependent evolution and pathway differentiation remains unclear. Herein, a nanoconfinement-enhanced MOF-derived catalytic membrane with dual reactive centers was developed to enable site-dependent *O evolution and the coexistence of radical and nonradical pathways. ZIF-67 was in situ grown on a stainless steel-cobalt hollow fiber membrane and pyrolyzed to construct Co/NC@SSCoM. The confined membrane structure promotes pollutant enrichment and interfacial mass transfer, while pyrolysis generates Co-Nx sites and oxygen vacancies (Vo) as dual active centers. Mechanistic investigations combining experiments and DFT calculations show that ozone activation forms *O at both sites, whereas its subsequent evolution differs. At Co-Nx sites, *O conversion to •OH is more thermodynamically favorable, whereas at Vo sites, *O tends to be preferentially stabilized. This site-dependent evolution of *O enables the coexistence of radical and nonradical pathways. Consequently, rapid atrazine degradation (k = 0.34 s⁻¹) is achieved, about 1000 times faster than single ozonation, with robust performance in real water matrices. This work provides new insights into reactive oxygen intermediate evolution for rational catalytic membrane design.

Microplastics (MPs) are widely recognized as particulate hazards, yet environmental aging releases a time-evolving pool of MP-derived dissolved organic matter (MP-DOM) that engages in photochemical and redox reactions. This work provides a critical overview of the aging mechanisms of MPs and the release characteristics of MP-DOM, with emphasis on its molecular properties and the intrinsic and extrinsic factors driving DOM release. Particular attention is given to the strong polymer dependence of MP-DOM, as different plastic classes can generate dissolved mixtures with distinct release kinetics, chemical profiles, and environmental reactivities. Insights into the unstable characteristics of MP-DOM are translated into measurable physicochemical reactions by evaluating its photochemical reactivity and interactions with natural minerals. Importantly, high methodological heterogeneity in experimental protocols hampers reliable comparisons across studies, underscoring the need for standardized leaching procedures in MP-DOM quantification and characterization. The role of MP-DOM in influencing the behavior of environmental pollutants, such as organic contaminants, metals, and antibiotic resistance genes, is critically assessed, particularly its contribution to disinfection byproduct formation, an ongoing concern in water quality management. Recent advances in understanding the ecological and biogeochemical impacts of MP-DOM are synthesized, highlighting its effects on cellular toxicity, microbial responses, and disruptions in element cycling and greenhouse gas emissions. Future directions include standardized aging protocols, rapid source attribution methods, and transferable models for predicting MP-DOM fate and ecological consequences under multistressor conditions. This review provides an updated synthesis of MP-DOM by linking its environmental behavior to ecological fate, advancing our understanding of the long-term ecological impacts and toxicity of plastics.

Soil cadmium (Cd) pollution is a persistent concern for soil quality, crop production, and food safety. Despite global concerns, spatial predictions of topsoil Cd remain challenging due to limitations in model accuracy, covariate representation, and nonlinearity handling. This study addresses these gaps by integrating 59,328 topsoil Cd samples worldwide to map global Cd exceedance probability and concentration distribution using classification and regression machine-learning models, with AUC of 0.90 and R² of 0.72, respectively. Variable importance analysis identifies climate factors (39.00%) and soil properties (34.01%) as the dominant factors associated with Cd exceedance probability, followed by geology (13.22%), topography (5.01%), and vegetation (4.58%), while anthropogenic contributions appear more localized at the global scale. High-resolution (1 km) maps of global soil Cd exceedance probability and predicted concentration distribution are generated. Under the moderate screening scenario, approximately 0.14% of global cropland (23,130 km²) overlapped with acidic high-soil-Cd-risk zones, mainly in China (15,201 km²), the UK (4956 km²), and Ireland (1382 km²). Approximately 1.24% of rice, 0.33% of wheat, and 0.22% of maize production were located in areas classified as high soil-Cd-risk zones, indicating priority areas for monitoring rather than direct evidence of grain Cd exceedance. These findings provide a spatially explicit basis for preliminary screening, targeted monitoring, and soil Cd management.

This study demonstrated the synergy between peroxymonosulfate (PMS) and p-benzoquinone (p-BQ) in the sulfamethoxazole (SMX) degradation under the ultraviolet (UV) irradiation. In the UV/p-BQ/PMS process, the SMX degradation showed positive dependence on the initial dosages of PMS, p-BQ and SMX. The variation of the observed pseudo-first-order rate constant (kobs) exhibited aligned with the speciation of SO52-across pH 7-10, and the anomalous decline of kobs emerged at pH 10-12. It suggested that SO52-might be significant for the SMX degradation. The quenching experiments and the electron paramagnetic resonance spectroscopy confirmed the dominant reactive oxygen species (ROS) (i.e., sulfate radicals (SO4 center dot-), hydroxyl radicals (OH center dot), singlet oxygen (1O2), peroxymonosulfate anion radical (SO5 center dot-)) in the UV/p-BQ/PMS process. The generation of SO5 center dot- might be attributed to the single electron transfer (SET) mechanism from PMS to the triplet excited-state ofp-BQ, which subsequently triggered the formation of SO4 center dot- and 1O2 via disproportionation. The possible degradation pathways of SMX were identified by LC-MS, including the hydroxylation, the cleavage of S-N bond, the nitration and the oxidation of amino group. Compared to p-BQ, methyl-p-benzoquinone, with an electron donating group, was found to suppress the activation of PMS, which validated the rationality of the SET mechanism. While tetrachloro-1,4-benzoquinone, with an electron withdrawing group, inhibited the SMX degradation by scavenging the generated radicals. Furthermore, the coexisting ions made no diffidence to the SMX degradation. The results provided the critical insights into the role of quinones in the PMS-based advanced oxidation processes for water treatment.

Traditional anti-corrosion coatings are susceptible to cracking and exhibit poor anti-fouling performance. In this work, hydrophobic alpha-zirconium phosphate (α-ZrP) particles were synthesized via a hydrothermal method and incorporated into polydimethylsiloxane (PDMS) to fabricate a micro-nano structured α-ZrP/PDMS superhydrophobic anti-corrosion coating. Compared with bare steel, the coated steel sheets demonstrated significantly enhanced corrosion resistance: the corrosion current decreased from 2.31×10 -3 mA/cm 2 to 1.12×10 -4 mA/cm 2 , the corrosion potential increased from -474.22 mV to -447.26 mV, and the polarization resistance rose from 8.96×10 3 Ω·cm 2 to 7.41×10 4 Ω·cm 2 . As a result, the anti-corrosion efficiency improved markedly from 36.20% to 98.70%.

Selenium (Se), though essential in trace amounts for biological systems, poses significant ecological and public health risks when present in aquatic environments at concentrations exceeding natural thresholds. To tackle this problem, a novel Zr-Ce composite oxide was synthesized via a tailored co-precipitation method. Structural characterization revealed that the material comprised nanoscale agglomerates with a specific surface area of 24.65 m2/g. Batch adsorption experiments demonstrated its remarkable affinity for Se species, attaining maximum uptake capacities of 83.81 mg/g for Se(IV) and 65.08 mg/g for Se(VI) under mildly acidic conditions (pH 5.0 +/- 0.1). The adsorption process was rapid, reaching equilibrium within approximately 24 h, and adhered to a pseudo-second-order kinetic model, suggesting chemisorption as the dominant mechanism. While parameters such as pH, coexisting ions, and the presence of humic substances affected the material's performance, variations in ionic strength exerted negligible influence. Intriguingly, Se removal involved a coupled adsorption-reduction process-the Ce component actively facilitated the reduction of both Se(VI) and Se(IV), whereas Zr component primarily contributed to their immobilization on the oxide surface. Reusability assessments and real water tests further confirmed the material's operational stability and practical applicability, underscoring its potential for long-term deployment in water purification and ecological restoration.

Diabetic foot ulcer (DFU) is a common and severe complication in diabetic patients, characterized by prolonged wound healing, susceptibility to infection, and a high risk of amputation. Its complex pathophysiology involves persistent hyperglycemia, chronic inflammation, neuropathy, vascular impairment, infection, and cellular dysfunction. Conventional treatments often fall short in addressing these multifaceted challenges, Therefore, formulating safe and effective treatment strategies holds significant clinical significance. In recent years, Microneedle Hydrogels have emerged as a novel drug delivery system due to their minimally invasive application, high drug loading capacity and controlled release characteristics, This review highlights the unique advantages of Microneedle Hydrogel systems, including their structural characteristics, drug delivery capabilities, and mechanisms in promoting ulcer healing. At the same time, the challenges currently faced in research and the future development directions were explored, aiming to provide references for further research and clinical application in this field.

Utilizing transition-metal activators to activate peroxymonosulfate (PMS) and mediate a combination of freeradical and non-radical pathways is an effective strategy for organic contaminant degradation. However, the performance of conventional catalytic materials is often constrained by low activation efficiency, insufficient active sites, and poor stability. Here, a heterostructured activator of CoO@Co3O4 was synthesized through the controlled reduction of Co3O4 nanosheets to enhance both its catalytic efficiency and structural stability. The optimized activator was employed to activate PMS for the degradation of sulfamethoxazole (SMX). The CoO@Co3O4-300/PMS system achieved 97.03% degradation of SMX (6 mg/L) within 15 min, demonstrating rapid and efficient removal of the target pollutant. The synergy of the heterostructure, abundant oxygen vacancies, and Co2+/Co3+ couples in CoO@Co3O4-300 facilitates electron transfer and PMS activation, thus accounting for the generation of abundant reactive species. Quenching and electron paramagnetic resonance (EPR) experiments verified the coexistence of free-radical (SO4 center dot- and center dot OH) and non-radical (1O2) pathways in the CoO@Co3O4-300/PMS system, with these species being identified as the primary active substances. The activator demonstrated excellent stability, maintaining an efficiency of 81.86% over five cycles. This study not only establishes CoO@Co3O4-300 as an efficient and stable PMS activator but also provides valuable insights into the removal of organic pollutants via synergistic radical and non-radical pathways.

This work investigated a novel pathway for selective singlet oxygen (O-1(2)) evolution through peroxymonosulfate (PMS) activation without O-2/center dot O-2(-) participation. The titanium dioxide/graphene/tri-iron tetroxide (TiO2-x/rGO/Fe3O4, TRF-5-500) nanomaterial with specific oxygen vacancies concentration was prepared to evaluate the crucial role of directed separation of photogenerated electron-hole (e(-)-h(+)) pairs in the PMS activation for imidacloprid degradation by quenching and probe experiments, in situ spectroscopy, and site-specific adsorption energy calculations. The TRF-5-500/PMS system achieved 99.9 % removal of imidacloprid under high O-1(2) generation (2.44 mu mol/L) within 30 min and demonstrated stable removal of > 80 % of pollutants within 2 h under natural sunlight in an extended plate reactor. The electron transfer mechanism suggests that h(+) could oxidize the adsorbed PMS on Ti sites to promote substantial O-1(2) evolution, while the self-disproportionation of hydroxyl radicals generates additional O-1(2). This work provides a potential strategy for selectively regulating reactive oxygen species and for practical wastewater treatment.

Photoactivated periodate (PI)-based advanced oxidation processes (AOPs) are effective for removing refractory micropollutants, but PI can hardly be activated by visible light alone. This study employed ubiquitous aquatic humic acid (HA) to boost visible light-driven PI activation. 2 mgC/L HA increased naproxen (NAP) removal in the Vis460/PI system from 10% to 75.8% at pH 7.0. The kobs of NAP rose from 0.064 min-1 to 0.185 min-1 with the PI concentration increasing from 25 μM to 100 μM. Quenching and probe experiments verified hydroxyl radicals (HO•) and ozone (O3) as the dominant species, with their contributions at 77.6%-93.2% and 13.9%-20.6% across pH 4.0-9.0, respectively. The excited triplet state (3HA*) was the key photoproduced reactive intermediate for PI activation. Longer visible wavelengths inhibited NAP degradation due to lower photon energy, while acidic conditions facilitated the reaction via higher PI quantum yield. Higher HA concentration generated more 3HA* to accelerate PI activation, and aromatic ketones were more likely precursors of the triplet excited state. The system efficiently degraded seven micropollutants, and Suwannee River NOM shared a similar activation role. This work offers a reliable approach for improving the visible light-activated PI system and novel insights into HA photochemical behaviors.

The occurrence of harmful algal blooms (HABs) poses serious ecological concerns. Photocatalytic oxidation has emerged as an ideal alternative to conventional algal removal strategies, owing to its minimal energy requirements. Here, we prepared a novel photocatalyst by fabricating molybdenum disulfide nanosheets with bismuth oxyhalide (MS/BBI). Successful construction of the heterojunction effectively facilitated the separation and migration of photogenerated carriers, thereby significantly enhancing the photocatalytic performance of the catalyst. The MS/BBI photocatalyst achieved 96.8% removal efficiency for Microcystis aeruginosa (M. aeruginosa) after 3 h light irradiation, which was higher than the performance of MoS2 and BBI alone. Comprehensive physiological analyses revealed substantial changes in cell activity, accompanied by electrolyte leakage, lipid peroxidation, disruption of photosynthetic and antioxidant systems, and depletion of intracellular organic matter. Notably, only the light-irradiated MS/BBI system resulted in irreversible damage to algal cells, completely suppressing the regrowth potential of algae. Experiments identified superoxide radicals as the predominant reactive oxygen species that mediated the defensive response in algal cells, triggering the production of extracellular polymeric substances, which in turn facilitated the self-flocculation of algal cells into flocs. The synergistic effect of photo-oxidation and flocculation enabled the efficient removal of M. aeruginosa. Furthermore, the solution after photocatalytic treatment demonstrated good biocompatibility, indicating a negligible environmental risk. This study reports a novel photocatalyst designed for the rapid removal of algae. It identifies a flocculation mechanism present during the photocatalytic process, providing fundamental understanding for future research on HABs control via photocatalysis.

Carbon-based aerogels (CAs) are ultralight three-dimensional carbon networks with hierarchical porosity and highly tunable surface chemistry. Unlike traditional inorganic aerogels, CAs uniquely combine continuous electrical conductivity with rich surface functionalities, enabling versatile use as adsorbents, catalysts, and electrode materials in water treatment. Their large surface area and abundant active sites drive efficient uptake of pollutants and high catalytic activity, while robust carbon frameworks confer chemical and thermal stability for easy regeneration and reuse. In this engineering-focused review, recent advances in CAs synthesis, modification, and environmental applications were critically examined. Through bibliometric analysis, the research focus on CAs in water treatment has shifted toward the direction of solar-driven and sustainable development. This review summarizes recent progress in the synthesis, modification, and application of CAs for environmental water treatment. Preparation strategies are analyzed, including the selection of organic precursors, gelation and drying methods (e.g., freeze-drying, supercritical drying), and post-synthesis functionalization, with attention to how pore architecture and surface chemistry influence performance. Key applications are evaluated, such as adsorption of heavy metals and organic pollutants, advanced oxidation processes (photocatalysis, electro-catalysis, persulfate/Fenton activation), and multifunctional separations including oil-water separation and desalination. Scale-up challenges and practical considerations are also addressed, covering cost, reproducibility, and pilot-scale studies that bridge laboratory materials to industrial water treatment systems. By linking struc-ture-property relationships with applied performance, this review identifies opportunities and challenges for translating CAs technologies into sustainable solutions for water purification.

Ferrate (Fe(VI)) has limited applications due to its slow reaction rate with micropollutants under neutral or alkaline conditions. This study presented sulfur-vacancy-rich nanoflower-structured MoS2 synthesized via a simple hydrothermal method, which effectively activated Fe(VI) to rapidly degrade micropollutants. Almost complete removal (98.4-100%) of various micropollutants (e.g., diclofenac (DCF), trimethoprim (TMP), etc.) was achieved within 5 min after adding a low dose of MoS2 (25 mg/L) to the Fe(VI) system, with the rate constants (kobs) 5.3-27.3 times higher than those of Fe(VI) alone. Probe experiments indicated that MoS2 promoted the generation of more intermediate iron species (Fe(V)/Fe(IV)) from Fe(VI), with Fe(V) accounting for 88.8% of the total contribution. Furthermore, by adjusting the concentration of sulfur vacancies (Sv) in MoS2, a relationship between sulfur vacancy abundance and degradation efficiency was established, providing the evidence for the critical role of sulfur vacancies in the activation of Fe(VI). Sv-rich MoS2 served as key electron-shuttling, facilitating the adsorption of Fe(VI) and accelerating electron transfer processes to promote Fe(V)/Fe(IV) generation. The MoS2/Fe(VI) system exhibited outstanding performance across a wide pH range and demonstrated strong resistance to common aquatic components (Cl-, SO42-, etc.). Remarkably, increasing the concentration of humic acid (HA) from 0 to 5 mg/L led to a near-complete degradation of DCF within 2 min, accompanied by a 3.9-fold increase in the kobs value. This phenomenon can be attributed to the electron-shuttling role of HA that synergistically enhanced interfacial electron transfer. Practical application results validated that this system could achieve excellent DCF removal efficiency (96.5-97.9%) in various real water. This work provides fundamental insight into the intrinsic mechanism of defect-engineered MoS2 activating Fe(VI), offering a sustainable and efficient strategy for water purification.

S-scheme heterojunctions excel in solar-driven water treatment and energy conversion, yet interfacial carrier relaxation remains insufficiently understood, with little insight into their catalytic-photothermal trade-off. Here, we construct a pi-d hybridized CoFe-based Prussian Blue Analogue/polyaniline heterostructure to regulate interfacial carrier behavior. Crystal field analysis reveals that pi electrons from polyaniline selectively inject into Fe 3d orbitals, reconstructing interfacial electric fields. Upon photoexcitation, carriers in Co/Fe 3d orbitals undergo a characteristic interfacial relaxation process (tau 3 = 913.2 ps) involving transfer toward pi*C-N orbitals, suppressing radiative recombination and enhancing nonradiative relaxation. This trajectory helps preserve highredox-potential electrons and holes for catalysis, while enabling interfacial carrier nonradiative relaxation to contribute to localized heat generation, revealing a carrier-relaxation-mediated coupling between catalytic oxidation and photothermal conversion at S-scheme interfaces. A photothermal catalytic evaporator based on this mechanism demonstrates promising performance for simultaneous volatile organic compound removal and clean-water production, proposing a dual-function strategy for solar-driven oxidation-distillation.

The integration of artificial intelligence (AI) with sustainable water management holds transformative potential for addressing global sustainability challenges. However, this progress is critically hindered by the slow, labor-intensive construction of large-scale datasets, particularly in identifying the relevant literature from thousands of candidates. Here, we present a hierarchical AI framework that ensures both high accuracy and transparency in literature screening. First, we develop a domain-tailored prompting strategy (3T+RAG) that grounds large language models (LLMs) in structured water-treatment knowledge, thereby improving classification accuracy and screening reliability. Evaluated on three manually curated domain datasets, LLMs achieved reliable literature screening with an average F1-score of 0.88, while operating 79 times faster at only 1.4% of the estimated cost of individual human annotation. To further enhance​ transparency and auditability, we introduce a multi-agent Reviewer-Reviewer-Arbiter (RRA) framework, in which two reviewer agents independently assess literature using the 3T+RAG prompting strategy, and an arbiter agent resolves disputes through reasoning-trace analysis. This architecture distinguishes reviewer disagreements from consistent decisions, allowing human review to focus on disputed articles and targeted quality control. Overall, this study establishes an efficient and reliable pathway for water-treatment literature screening, providing a robust foundation for large-scale dataset construction and accelerating sustainable water management.

Peroxymonosulfate (PMS) activation by iodide (I-) has emerged as a promising approach for degrading emerging organic contaminants (EOCs), but elevated I-levels often lead to excessive formation of iodinated by-products (I-BPs). The roles of trace I-and Fe(II) in PMS-based systems under environmentally relevant conditions remain poorly understood. This study demonstrates that trace levels of I-and Fe(II) can synergistically activate PMS to rapidly generate highly oxidative species including hydroxyl radicals (HO center dot), sulfate radicals (SO4 center dot-), singlet oxygen (1O2), iodine radicals (I center dot), diiodide radicals (I2 center dot- ), and hypoiodous acid (HOI) during the rapid reaction stage. Notably, tetravalent iron was not detected. Consequently, the low-concentration I-/Fe(II)/PMS system markedly enhanced the degradation of representative EOCs, such as sulfamethoxazole (SMX), with I center dot and SO4 center dot identified as the dominant reactive species. The Ecological Structure-Activity Relationships model predicted substantial reductions in acute and chronic toxicities following SMX degradation. Moreover, trace Fe(II) significantly suppressed the formation of typical I-BPs commonly observed in the I-/PMS system. These findings reveal that both I-and Fe(II) at trace levels synergistically activate PMS to enhance EOCs degradation and mitigate toxicity in shale gas wastewater, while maintaining nearly constant pH and ensuring cost-effective operation.

An innovative analytical approach was established for quantifying Fe(VI) concentrations in the 0.47-40 mu M range. This technique exploited the electron transfer reaction between Fe(VI) and N,N-diethyl-p-phenylenediamine (DPD), generating a stable radical cation species (DPD center dot+) with characteristic absorbance at 551 nm in spectroscopic detection. The increase in the absorbance of the formed DPD center dot+ at 551 nm was linearly related to the added Fe(VI) concentration. The formed DPD center dot+ was found to be stable in synthetic water samples at pH 5-7 and real water samples. The stoichiometric relationship of the formed DPD center dot+ to Fe(VI) was 1 : 1 in reaction of Fe(VI) with excess DPD in 300 mM phosphate buffer at pH 6, which was lower than that in lower concentration of phosphate, due to the inhibiting impact of phosphate on the oxidation capacity of Fe(V) with DPD. Demonstrating a molar absorptivity of 2.08 x 10(4) M-1 cm(-1) at 551 nm, the Fe(VI)-DPD method exhibited broad applicability while maintaining accuracy across diverse environmental water matrices. This methodology exhibited superior detection sensitivity, with detection limits established at 0.47 mu M (LOD) and 1.57 mu M (LOQ). The oxidizing capacity of the complexed Fe(V) followed the order: carbonate-Fe(V) > borate-Fe(V) > phosphate-Fe(V) > pyrophosphate-Fe(V). The ratio of the formed DPD center dot+ to consumed Fe(VI) decreased with the increasing concentration ratio of pyrophosphate to Fe(VI) (2.5-3.6) at pH 5, indicating that pyrophosphate inhibited the oxidizing capacity of Fe(VI) to Fe(V) using DPD. The developed DPD probe method demonstrated reliable applicability in characterizing Fe(VI) reaction pathways due to its high sensitivity (2.08 x 10(4) M-1 cm(-1)) and minimal matrix interference.