The ozone (O3)-hydrogen peroxide (H2O2) process (peroxone) is a promising advanced oxidation technology for refractory organic wastewater but is strongly pH-dependent, operating efficiently mainly under alkaline conditions, which hinders its use in acidic matrices. Here, we report a trace Mn(II)-mediated peroxone that sustains fast pollutant degradation and oxidant activation across acidic to alkaline pH conditions. The core is a transient Mn(III) intermediate maintained by rapid Mn(II)/Mn(III) redox cycling, with H2O2 serving both as the HO• precursor and as a redox mediator. This dynamic cycle continuously generates HO• while suppressing unproductive oxidant consumption. Kinetic tests show that Mn(II) increases the pseudo-first-order rate constant (kobs) for electron-poor atrazine to 1.21 min-1 even at a pH value of 3.0, which is 22.9-fold higher than the classical peroxone. Spectroscopic and electrochemical analyses further indicate that H2O2 inhibits the buildup of catalytically inactive Mn(IV)/Mn(V), stabilizing active Mn(III). The terminal Mn(IV) is captured as readily separable MnO2 solids, ensuring catalytic turnover and minimal dissolved Mn. Overall, the Mn(II)-mediated peroxone achieves >90% atrazine removal from pH 3.0 to 11.0. In a continuous-flow reactor, the constructed system sustains high efficiency while tolerating complex water matrices. Ecotoxicity assays (plant germination, zebrafish embryo development, and bacterial proliferation) and life cycle assessment confirmed lower environmental risks than O3 and Fenton processes. These results establish transient Mn(III) as a pivotal HO•-generating species and provide a robust, pH-resilient, and environmentally compatible framework for next-generation AOPs targeting persistent organic pollutants in diverse water matrices.

Membrane technology has become a critical platform for advancing water pollution control from standard-compliant discharge toward high-quality water reclamation, owing to its high separation selectivity, modular configuration, compact footprint, and compatibility with process intensification. Despite its broad application in industrial wastewater treatment, drinking water purification, and wastewater reuse, its field-scale performance remains constrained by a persistent mismatch between material-level advances and engineering-scale requirements. In particular, insufficient attention to scenario-specific water matrices, process coupling, fouling evolution, and life-cycle operation and maintenance has limited the translation of membrane performance into durable remediation efficiency. This viewpoint revisits the development logic of membrane technologies for water remediation from a full-chain application perspective, moving beyond the conventional material-centered optimization paradigm. We propose a three-dimensional framework that integrates scenario-oriented membrane design, synergistic process empowerment, and long-term operational regulation. This framework emphasizes that next-generation membrane systems should evolve from passive separation barriers into adaptive, integrated, and serviceable remediation platforms. By identifying key bottlenecks and linking them with emerging industrial demands, this work provides a forward-looking perspective for developing efficient, resilient, and sustainable membrane technologies for water remediation.

Ferrate-based advanced oxidation processes (Fe(VI)-AOPs) show promise for antibiotic abatement in water, but their practical application is typically limited by pH sensitivity, unstable active species, and insufficient electron transfer in real water matrices. To address these issues, we developed a novel ethylenediaminetetraacetic acid (EDTA)-bridged Mn(II)/Fe(VI) bimetallic synergistic system. Such a unique system could achieve 96.26% degradation of target antibiotics within 2 min via a non-radical direct electron transfer pathway, with stable performance across a wide pH range (5.0-9.0) relevant to natural and engineered water systems. Comprehensive characterization confirmed that EDTA functioned as a ligand to stabilize Mn(II) by complexation, suppressed the disproportionation of Mn(III) intermediates, key processes that enhanced pollutant removal. Moreover, the EDTA-Mn complex acted as an electron mediator, facilitating the conversion of Fe(VI) to highly reactive high-valent iron-oxo species (Fe(IV)=O and Fe(V)=O) and establishing a synergistic reaction pathway of ligand regulation-metal cycling-electron transfer-high-valent iron generation. Notably, computational toxicology combined with multi-level biological assays (microbial inhibition, phytotoxicity, and animal developmental toxicity) demonstrated that the system could effectively degrade antibiotics and also substantially reduce their acute and chronic ecotoxicity, addressing a critical gap in conventional AOPs that often overlook post-degradation ecological risks. This study systematically clarified the molecular mechanisms, catalytic oxidation performance, and environmental safety of the ligand-bridged bimetallic system, providing a robust basis for developing green, stable, and scalable water treatment technologies suitable for real-world antibiotic remediation.

Artificial photosynthesis for sustainable H2O2 production is the key to solve energy and environmental challenges, yet is hindered by inefficient charge dynamics and sluggish interfacial kinetics. To address this, an orcinol/fluorescein-formaldehyde resin (O/F-Resin) is hydrothermally synthesized, which features conjugationenhanced donor-acceptor (D-A) configurations of benzenoid-xanthene-quinoid structures. The O/F-Resin delivers outstanding H2O2 yields with long-term stability and demonstrates great potential in photocatalytic-Fenton systems for degrading organic contaminants. Mechanism studies reveal that O/F-Resin facilitates H2O2 and O2 formation via indirect 2e- oxygen reduction reaction and 4e- water oxidation reaction. Theoretical calculation analysis identifies the xanthene structures, quinoid units, and methine-bridge as the critical active centers. The DA couples enable efficient electron transport from xanthene to quinoid via extended It-conjugation methinebridge, which acts as reaction sites to promote favorable formation of key intermediates (*O2, *OOH, and *H2O2) and desorption of H2O2 in 2e- ORR, thus critically optimizing the charge and reaction kinetics. Life cycle assessment suggests that O/F-Resin with high-performance D-A architectures enable cost reduction of synthesis energy costs for H2O2 production through lower operational energy demand. This facile hydrothermal synthesis makes scalable production of fluorescein-based phenolic resins possible, and provides insights for designing efficient green resin photocatalysts.

Electrochemical nitrate reduction reaction (NO3−RR) offers a sustainable route for ammonia (NH3) synthesis as a promising substitute for the energy-intensive Haber-Bosch process. In this work, a series of Cu-Co bimetallic electrocatalysts are fabricated, among which Cu2Co6 delivers the optimal catalytic performance. With an initial NO3− concentration of 1400 ppm, Cu2Co6 achieves an ultrahigh Faradaic efficiency (FE) of 99.8% toward NH3, a remarkable NH3 yield rate of 64.42 mg·h−1·cm−2, and can lower residual nitrate concentration to less than 1 ppm within 4.5 h. The outstanding NO3−RR activity stems from a unique synergistic relay catalytic mechanism between Cu and Co dual active sites. Cu sites exhibit highly selective reduction capability to drive the initial conversion of NO3− into NO2− intermediates. Meanwhile, Co sites continuously catalyze the dissociation of interfacial water to generate abundant adsorbed hydrogen (*H) and hydroxide (OH−) intermediates, which timely hydrogenate the in-situ formed NO2− and propel the complete conversion of NO3− into NH3, effectively avoiding intermediate accumulation and competing side reactions. When employed as the cathode of a rechargeable Zn-NO3− battery, the Cu2Co6 electrode realizes a peak power density of 58.75 mW·cm−2 and maintains stable charge-discharge cycling for up to 100 h at 60 mA·cm−2. This work develops a high-performance bimetallic electrocatalyst that demonstrates a feasible strategy to concurrently produce NH3 and output electrical energy via NO3−RR.

Ferrate(VI) (Fe(VI)) is an environmentally benign oxidant for water purification, yet its practical application is hindered by pronounced pH dependence and inefficient activation under near-neutral conditions. Herein, we developed an amphoteric oxide regulation strategy for heterogeneous Fe(VI) activation under unbuffered conditions using boron-doped ZnO as a model catalyst. Boron incorporation through a scalable ball-milling-calcination process reconstructed the electronic structure of ZnO, generating electron-enriched BOZn coordination sites and abundant oxygen vacancies. These structural features enhanced Fe(VI) adsorption and facilitated interfacial electron transfer, accelerating the reduction of Fe(VI) to high-valent iron intermediates (Fe(V)/Fe(IV)) and promoting the formation of reactive oxygen species, including HO and O-2(-). As a result, a dual oxidation pathway dominated by high-valent iron species and assisted by radical oxidation was established. This synergistic pathway enabled rapid degradation of the antibiotic sulfamethoxazole over a broad initial pH range of 3.0-10.0 without external buffering, with an apparent rate constant more than eight times higher than that of Fe(VI) alone, accompanied by enhanced mineralization. Mechanistic investigations revealed that the BOZn-regulated electronic structure governed Fe(VI) activation and modulated the balance. The system exhibited strong resistance to coexisting water constituents, effectively removed diverse organic contaminants, maintained >98% pollutant removal in a 50 L continuous-flow reactor, and achieved efficient detoxification. This work demonstrates a coordination-site engineering strategy based on BOZn motifs for enhanced Fe(VI) activation, providing a mechanistic and practical foundation for sustainable purification of complex water matrices.

This work develops a self-regulating calcium peroxide/ozone (CaO2/O3) system for treating refractory industrial wastewater. The study integrated comprehensive batch tests and 60L pilot-scale experiments with multiple mechanistic probes, including hydrolysis-pathway blocking, CaO2 morphology characterization, electrochemical analysis, and theoretical calculations. The system achieved 96.7% nitrobenzene degradation within 18min over pH 3.0-11.0, enhanced O3 utilization by 38.4%, removed >81.7% of phosphorus and heavy metals by precipitation, sustained >83.8% COD removal for 120h in real wastewater treatment, and lowered carbon emissions by 74.5% and treatment costs by 37.1% compared to the Fenton process. These results demonstrated that the CaO2/O3 system effectively coupled pollutant mineralization with simultaneous resource recovery through a heterogeneous autocatalytic HOO-CaO2-O3 intermediate pathway. By establishing a low-carbon and economically viable platform, this work promotes the practical application of next-generation oxidation technologies for complex industrial effluents.

Heterogeneous Fenton-like systems activated by peroxymonosulfate represent promising platforms for organic wastewater treatment but are significantly hampered by competing adsorption and catalytic oxidation processes at identical active sites. To resolve this critical bottleneck, we develop a diverting dual-site catalyst comprising nitrogen-vacancy (Nv) sites precisely integrated adjacent to iron (Fe) single-atom sites within a carbon nitride framework. This spatially optimized configuration markedly enhances electron mobility and accelerates electron-hole separation under visible-light irradiation, thus enabling the concurrent generation of radical and non-radical oxidizing species. Consequently, the catalytic activity is substantially elevated. Mechanistic insights reveal that Nv sites preferentially anchor pollutants through selective adsorption, while the neighboring Fe sites actively facilitate oxidant activation, establishing a synergistic electron-transfer cascade that significantly boosts pollutant degradation kinetics and catalyst durability across various operational scenarios. Comprehensive experimental analyses coupled with theoretical simulations rigorously validate this dual-site catalytic mechanism. Additionally, life-cycle assessment (LCA) and electrical energy per order (EE/O) evaluations demonstrate the economic viability and reduced environmental impacts of the developed catalyst system. Furthermore, the integration of machine learning methodologies optimizes catalytic performance and elucidates the discrete functional contributions of the dual-site arrangement. Collectively, this work establishes an advanced framework for single-atom catalyst design, paving the way toward sustainable, efficient, and eco-friendly wastewater remediation technologies.

Heterogeneous advanced oxidation processes (HG-AOPs) can efficiently remove persistent pollutants but are constrained by catalyst deactivation from polymeric deposits and by energy- and chemical-intensive regeneration. We report a conductive packed-bed reactor that couples continuous treatment with in-situ electrochemical regeneration, maintaining high pollutant removal across diverse contaminants and complex matrices. Upon loss of activity due to catalyst deactivation, applying a mild current with low-cost H2O2 restores performance without reactor downtime. Mechanistic analyses show that electrochemical modulation lowers surface lipophobicity and weakens the interaction between polymeric products and the catalyst, enabling their desorption. Meanwhile, electrogenerated •OH promotes the coupling of residual phenolic polymers into insoluble aggregates and mineralizes quinoid compounds, recovering interfacial mass and electron transfer. Industrial coking wastewater can be continuously treated using a series-parallel reactor system, which alternates between oxidation and regeneration phases. This approach maintains over 80% total organic carbon removal efficiency for more than 300 hours of operation. Compared with conventional advanced oxidation processes, this strategy reduces operating costs by ~68%, minimizes external chemical inputs, and avoids high-temperature regeneration. The reactor architecture and regeneration logic are scalable, compatible with distributed deployments, and readily retrofittable to existing units, providing a sustainable pathway to extend catalyst lifetimes, lower resource intensity, and advance next-generation oxidation technologies.

The management and disposal of sludge remain a pressing challenge in municipal wastewater treatment plants. Converting sludge into biochar represents a promising pathway for waste reduction and resource recovery. However, the existing literature on performance enhancement methods and characterization techniques of biochar is rather scattered and lacks systematic integration. This review aims to provide a comprehensive and up-to-date analysis of sludge-based biochar, focusing on its preparation, activation, modification, and post-treatment strategies. Besides, key characterization approaches were systematically discussed, including surface area and porosity, ash content, acidity and basicity, elemental composition, and spectroscopic techniques. This work offers a theoretical foundation and technical guidance for the application of biochar, with significant implications under the “carbon peak” and “carbon neutrality” framework.

Polymerization-based wastewater treatment offers reduced oxidant demand and product recovery, yet practical application is hindered by catalyst fouling and unselective reactions due to single-site competition. Here, we report a readily synthesized and scalable ZnO/CuO catalyst featuring dual functional sites that decouple pollutant and oxidant activation. Zn sites preferentially adsorb/activate organics, whereas Cu sites predominantly activate the oxidant. This site differentiation programs two pathway regimes governed by pollutant electronic structure: electron-transfer-mediated polymerization for electron-rich substrates and radical-induced mineralization for electron-deficient substrates. Importantly, radicals generated during mineralization depolymerize the accumulated foulant layer in situ, effecting autonomous catalyst regeneration with a 2.5-fold performance recovery and reduced external regeneration demand. Process performance is validated in a 200 L self-circulating reactor, maintaining 98% removal efficiency for both pollutant classes over ten cycles. Toxicological profiling across multiple biological models, supported by metabolomics, confirmed effective detoxification of multi-pollutant wastewater, including restoration of normal metabolic function in zebrafish (e.g., lipid and glutathione metabolism). This study establishes a dual-site cooperative catalysis framework that leverages intrinsic wastewater chemistry for self-regeneration, showcasing a complete trajectory from atomic-scale design to reactor-scale implementation.

Singlet oxygen (O-1(2)) offers high selectivity for organic pollutant oxidation while providing potent bactericidal activity, yet constructing heterogeneous photoactivation systems that can produce (1)O(2)efficiently and cleanly remains challenging. Herein, we report a scalable salt-templated crystalline carbon nitride O-1(2)-dominated peroxymonosulfate photoactivation pathway for concurrent wastewater disinfection and contaminant removal. Relative to amorphous bulk carbon nitride, the crystalline type exhibits strengthened visible-light absorption and improved charge separation, achieving an apparent rate constant (kobs) of 6.12 min(-1) M-1 for pollutant removal, approximately 51.0-fold higher than the monomer. Mechanistic diagnostics show >94% selectivity to O-1(2), suppressing radical pathways and enabling targeted transformations. Integrated ecotoxicity assays and complementary computations indicate that O-1(2)-mediated degradation substantially lowers predicted ecological risk compared with non-selective oxidation. In a continuous-flow U-shaped reactor, such a constructed system sustains robust bacterial inactivation over 240 min of operation. Life-cycle assessment and energy metrics further support practical deployment, with encompassing energy efficiency (EE/O) reduced from 19.20 to 0.38 kWh L-1. The system achieves high disinfection efficacy in real medical wastewater, establishing a generalizable strategy to couple selective (1)O(2 )chemistry with heterogeneous oxidant photoactivation for sustainable water purification and disinfection.

Per and polyfluoroalkyl substances (PFAS) have emerged as ubiquitous contaminants in municipal solid waste (MSW) landfill leachates due to their widespread industrial applications, environmental persistence, and the disposal of PFAS-containing waste in landfill. This study presents a multi-regional investigation of PFAS occurrence, influencing factors, and treatment performance in 17 landfill leachates and 9 corresponding effluents across China. Sum PFAS concentrations in raw leachates ranged from 634 to 46,400 ng/L, with short-chain perfluoroalkyl acids (PFAAs) dominating the compositional profile (65.4 to 97.2%). Landfill age exhibited a significant positive correlation with PFAS levels (p ≤ 0.05). Moreover, physicochemical parameters of leachate such as electrical conductivity and ammonia nitrogen exhibited strong positive correlations with PFAS concentrations (p ≤ 0.05), while meteorological variables showed compound-specific (perfluorobutanoic acid, PFBA and perfluorodecanesulfonic acid, PFDS) associations. PFAS concentrations in the treated effluents ranged from 6.29 to 7390 ng/L, with short-chain PFAAs dominating. Among the evaluated technologies, two-stage (TS) membrane bioreactor (MBR) combined with membrane separation systems achieved the lowest effluent concentrations (<10 ng/L) and the highest apparent removal efficiencies (up to ∼99.9%) in this dataset. However, removal effectiveness varied considerably across compounds, especially for short-chain PFAAs and PFAA-precursors. Overall, this study provides an assessment of PFAS occurrence and treatment performance in landfill leachate systems, highlights key environmental and operational factors, and provides insights for improving PFAS management in landfill leachate treatment.

Iron-carbon composites (FS@WSC-x/y) were synthesized from Fenton sludge (FS) and walnut shells (WS) via hypoxic calcination for sulfadiazine degradation. By varying FS/WS mass ratios (x) and calcination temperatures (y), optimal conditions (x = 1, y = 700 degrees C) were identified, maximizing degradation efficiency. Reaction conditions were further optimized to 40 mu M sulfadiazine, 10 mM H2O2, pH 2.0, and 0.050 g FS@WSC-1/700, achieving 95 % degradation within 120 min.

Fenton iron sludge is produced in large quantities in industrial wastewater treatment plants. However, the high disposal cost limits its resource reuse. In this study, we explore the feasibility of Fenton sludge reutilization in anammox processes by synthesizing a novel Fenton sludge-graphite felt (Fe/GF) carrier to promote anammox. Results showed that nitrogen removal efficiency reached 72.85 % with the Fe/GF carriers under anoxic conditions, while it was 52.68 % in the control. This efficiency showed a significant effect of iron loading (p <= 0.01). Loaded iron in Fe/GF carriers could promote the cellular biosynthesis and metabolic ability of anammox bacteria, leading to a 23.89 % relative abundance of Ca. Kuenenia (12.46 % in the control) within the first 40 days. Metagenomic analysis showed that Fe/GF carriers facilitated the enrichment of diverse microbes with functional genes encoding nitrogen transformation, which contributed to the nitrogen removal performance. This study presents a promising approach to the reutilization of Fenton sludge in anammox processes.

Traditional heterogeneous photocatalytic systems coupled with oxidant activation hold great promise for environmental remediation but are constrained by radical scavenging and nonselective oxidation. Here, we introduce an overlooked photoswitch-mediated electron transfer (PSMET) mechanism that circumvents reactive oxygen species by enabling direct, ultrafast electron transfer from pollutants to oxidants through a photoactive mediator. Using environmentally benign bismuth oxyiodide as a model catalyst under visible-light irradiation, we achieve unprecedented degradation rates for various electron-rich pollutants such as sulfamethoxazole (t1/2 <2.0 min). This mechanism exhibits pollutant-dependent oxidant utilization mode and selective pollutant degradation characteristics. Mechanistic analyses reveal the formation of a high-potential electron-transfer pathway activated by photoexcitation, directly coupling pollutant oxidation to oxidant reduction within a single electron-transfer cycle. Frontier molecular orbital calculations further demonstrate that the narrow bandgap and p-type semiconductor characteristics selectively facilitate electron extraction from contaminants to oxidants. Remarkably, this PSMET mechanism displays universal applicability with diverse oxidants, maintaining >98% pollutant removals even in complex aqueous matrices and continuous-flow systems. Furthermore, the mechanism allows precise optical control over reaction initiation and termination, offering unparalleled spatiotemporal regulation for sustainable wastewater treatment. Our findings redefine photocatalytic oxidation paradigms and open new pathways toward energy-efficient, optically programmable, and environmentally sustainable remediation technologies.

Stable removal of per- and polyfluoroalkyl substances (PFAS) remains a challenge for wastewater treatment plants (WWTPs). This study evaluated the seasonal behavior of 26 target PFAS throughout all stages of a Bacillusbased bioreactor (BBR) system. Total PFAS concentrations were 74.05 ng/L (summer) and 76.64 ng/L (winter), with perfluoropentanoic acid (PFPeA) dominating (2.49-44.70 ng/L). The grit chamber showed positive removal, while the BBR facilitated biotransformation of precursors into short-chain PFAS and 6:2 fluorotelomer sulfonate (6:2 FTS). The secondary clarifier exhibited desorption of long-chain PFAS, causing water recontamination. Advanced stages involved complex processes like UV-induced reactions. Overall removal efficiency was 59% in summer but decreased to 38% in winter. The solid-water distribution coefficient indicated enhanced PFAS adsorption during colder months, with perfluoroalkyl sulfonic acids (PFSAs) showing chain-lengthdependent adsorption. The WWTP reduced the daily & sum;PFAS mass from influent to effluent, with partial retention in sludge. Environmental risk assessment revealed negligible ecological risks for aquatic taxa from effluent and activated sludge concentrations. This research provides insights into PFAS fate in WWTPs, highlighting the need to investigate biotransformation in bioreactors and optimize advanced treatment technologies.

Ferrate (Fe(VI)) and periodate (PI) are powerful oxidizing agents that have emerged as significant contributors to advanced wastewater treatment methods. Their synergistic interaction has been recognized for its enhanced oxidative capabilities. However, the presence of organic and inorganic ions, particularly halide ions such as chloride (Cl-), bromide (Br-), and iodide (I-), can significantly influence oxidation kinetics and the transformation of organic pollutants. This study systematically investigated the oxidation mechanisms of the Fe(VI)-PI system and its performance in the presence of these halide ions. Dynamic experiments showed that halide ions markedly affected the activity of the Fe(VI)-PI system. Specifically, in the presence of Cl-, the degradation efficiency of sulfamethoxazole (SMX) increased by 4.8% at pH 7.0 and 22.2% at pH 8.0. Similarly, Br- enhanced the degradation efficiency by 12.5% at pH 7.0 and 26.2% at pH 8.0. In contrast, I- completely inhibited the degradation process, likely due to their interaction with the oxidant. Additional removal experiments, detection tests, and electron spin resonance (ESR) analyses revealed that introducing halide ions significantly altered the composition of reactive species. Cl- and Br- promoted the formation of center dot OH and facilitated the reduction of Fe(VI) to Fe(IV)/Fe(V) species. This effect was strongly dependent on pH, which in turn influenced the degradation pathway. Product analysis and toxicity assessments further indicated that halide ions might lead to the formation of halogenated byproducts in the Fe(VI)-PI system, with pH playing a crucial role in regulating this process. This study provides a deeper understanding of the influence of halide ions on oxidation reactions and highlights their role in controlling the degradation of micropollutants and the formation of disinfection byproducts in water treatment.

Poly(heptazine imide) (PHI) is a representative crystalline carbon nitride material widely utilized as a photocatalyst for hydrogen production. However, the practical photocatalysis performance of PHI is restricted by its limited crystallinity and low photo-generated charge-carrier utilization efficiency. To solve these problems, herein, we report a highly crystalline sulfur-doped PHI (S-PHI) synthesized using the sulfur-containing compound 1H-1,2,4-triazole-3-thiol as a precursor. The introduction of sulfur during synthesis promotes polymerization and enhances the crystallinity of PHI, with sulfur incorporated into the framework of PHI as a form of sulfur doping. Consequently, S-PHI exhibits improved light utilization, an enlarged surface area, and enhanced charge-carrier separation and migration efficiency compared to PHI synthesized from melamine, with apparent quantum yield (AQY) of photocatalytic H2 evolution achieving 13.6% at 420 nm and impressive value of 2.8% at 520 nm.

Polymerization-based oxidation processes (PBOP) present a promising alternative to chemical and energy-intensive advanced oxidation processes (AOPs) for removing emerging pollutants in water treatment. By reducing oxidant consumption and minimizing carbon emissions, PBOP offers a more sustainable solution. However, the polymerization products generated in these processes pose significant sustainability challenges, including potential toxicity and catalyst deactivation. Firstly, the polymeric products formed during PBOP exhibit increased hydrophobicity (higher Kow), which correlates strongly with enhanced bioconcentration potential (KB) and aquatic toxicity. Residual dissolved polymers, or those reentering the environment, present ecological risks through non-specific narcosis (due to their lipophilic nature) and potential specific toxicity arising from retained functional groups, such as benzene rings. Secondly, in heterogeneous catalytic systems, these polymeric byproducts tend to adsorb onto catalyst surfaces via hydrophobic interactions and van der Waals forces. Over time, this deposition blocks active sites, impairs reactant adsorption and activation, potentially repels oxidants, and disrupts electron transfer, ultimately leading to catalyst deactivation. This mechanism, which was often previously attributed to "degradation intermediates," is now understood to be driven by the accumulation of polymeric products. Several strategies have been proposed to address these challenges and ensure the sustainable implementation of PBOP. These include coupling PBOP with energy-efficient microfiltration or coagulation processes to remove polymeric byproducts effectively and develop efficient and environmentally friendly catalyst regeneration technologies. Promising approaches involve in-situ electrochemical regeneration or the transformation of polymers into catalytic sites, which also enable resource utilization. A comprehensive understanding of the environmental toxicity of polymeric products, coupled with insights into the mechanisms of catalyst deactivation, is essential for advancing PBOP technology in an environmentally responsible manner.