Mechanism Of Peroxymonosulfate Activation Research Articles

Activation of peroxomonosulfate by manganese-containing non-homogeneous catalysts prepared via a soft template calcination strategy for efficient degradation of carbamazepine

Manganese (Mn)-containing inhomogeneous catalysts have demonstrated potential to activate peroxymonosulfate (PMS), but may be constrained by low efficiency and poor resistance to environmental disturbances. According to the soft template calcination strategy, g-C3N4 with Mn doping was synthesized to improve PMS activation through an effective Mn(II)/Mn(III)/Mn(IV) cycle. The constructed Mn25@CN/PMS system achieved complete and rapid removal of carbamazepine (CBZ) at 0.3 g/L catalyst and 2 mM PMS. Its corresponding rate constant of pseudo-first-order was 0.3424 min−1, and it was 3424 and 16.15 times higher than that of pure g-C3N4/PMS system and CN/PMS system, respectively. More strikingly, the catalysts exhibited excellent resistance to environmental impacts, with CBZ removal rates exceeding 95% under the influence of different anions, cations, aqueous pH values, and humic acid (HA) concentrations. Subsequently, it was proposed a reliable catalytic mechanism for CBZ removal and PMS activation derived from electron paramagnetic resonance (EPR) tests and quenching experiments. The O2·- and 1O2 played a major role in the CBZ removal process. This research provides a perspective soft template strategy for PMS activation using highly efficient catalysts with high resistance to environmental impacts, which provides new ideas to alleviate environmental issues.

Nanostructured NiCo2S4 immobilized on nickel foam as recyclable catalyst for activating peroxymonosulfate toward doxycycline degradation: Performance and mechanism

The existing powder catalysts used in sulfate radical-based advanced oxidation processes (SR-AOPs) commonly suffer from severe limitation due to the difficulty of recycling and inadequate exposure of the active site. In this work, spinel sulfide (NiCo2S4) was uniformly grown on 3D nickel foam (NF) through a one-step hydrothermal route for the activation of peroxymonosulfate (PMS) toward highly efficient degradation of doxycycline (DOX). Due to the synergistic effect of Ni and Co in the NiCo2S4, the NiCo2S4/NF (0.6 g/L) combined with PMS (3.0 mmol L-1) can promote a nearly complete degradation (98.2 %) toward 0.3 mmol/L DOX within 6 min. Density functional theory (DFT) calculations illustrated that the NiCo2S4/NF can adsorb PMS through a unique Ni-S-Co structure and “conducting bridge” mode of NF, accelerating the electron transfer from NiCo2S4/NF to PMS and the subsequent O-O bond cleavage. Especially, the Co/Ni dual-site enhanced the adsorption of PMS and promotes electron transfer to form surface-activated PMS complex (catalyst-PMS*), leading to the generation of surface-bound reactive oxygen species (ROS) on the NiCo2S4 surface. Quenching experiments and ESR tests demonstrated that radicals such as SO4•-, 1O2, •OH and surface-bound ROS play a vital role in DOX degradation. Moreover, the potential mechanism and pathway of DOX degradation are reasonably deduced by investigating and analyzing the intermediates with liquid chromatography-mass spectromsetry (LC-MS). Consequently, this study provides a deep insight on the systhsis of spinel sulfide and its intrinsic mechanism of PMS activation toward organic contaminant degradation.

Mechanistic insights into ultrafast degradation of electron-rich emerging pollutants by waste cyanobacteria resource utilization

Biochar has the issues with inadequate stability and low catalytic activity. In this study, two-step ball milling method was applied to synthesis carbon nitride co-modified cyanobacteria biochar (CN-BC). The optimized CN-BC can effectively activate peroxymonosulfate (PMS) to degrade emerging pollutants. The degradation rate constant of enrofloxacin in the CN-BC/PMS system reached 0.506 min−1, and 95 % of enrofloxacin could be effectively degraded within 10 min. Free radical quenching experiments and electrochemical experiments confirmed that the electron transfer and 1O2 were the main pathways in the CN-BC/PMS system. The CN-BC/PMS system has selective degradation of electron-rich pollutants, and the pollutants containing electron-donating groups are more easily degraded than those containing electron-withdrawing group. The selective degradation pathway of pollutants by CN-BC was further analyzed using density functional theory (DFT). Continuous flow CN-BC/PMS membrane system showed long-term abatement of emerging pollutants. This study improves the understanding of the mechanism of PMS activation by cyanobacterial biochar catalysts and provides a new pathway for membrane-based domain-limited catalysis.

Advanced activation of peroxymonosulfate by NiFe-LDH/CeO2 heterostructure photocatalysts toward medical wastewater remediation

The great harm of antibiotic residues in medical wastewater to the ecological environment and human health has become the focus of social attention. Herein, we designed a new peroxymonosulfate (PMS) activation system by in-situ anchoring NiFe-LDH nanosheets into CeO2 (NFC) as a heterogeneous photocatalyst to degrade pollutants. The NFC/PMS/Vis system showed excellent and rapid degradation effect on tetracycline (TC) under the synergistic effect of photocatalysis and PMS activation, and the removal rate of TC was about 98.8 % within 40 min. The chemical compositions, microstructures, and optical properties of synthesized photocatalysts were studied by a series of characterization methods such as XRD, XPS, SEM, TEM and UV-DRS. The effects of various reaction systems and operating parameters such as initial concentration, catalyst dosage, and PMS concentration on the degradation efficiency of TC over optimized NFC-4 composite were investigated. The active species in the reaction system and the dominant SO4− were confirmed by quenching tests and electron paramagnetic resonance (EPR) measurements, and a plausible photocatalytic mechanism for PMS activation and pollutant remediation was further proposed.

Atomically dispersed Co atoms anchored on sulfur vacancies to accelerate the electron transfer process and efficiently degrade sulfamethoxazole

Molybdenum disulfide serves as an ideal support for single atom catalysts (SACs), offering not only coordination elements but also abundant active sites, such as surface defects and vacancies. Herein, a novel Co-SAC (MoSO-Co-C) containing a four-coordinated configuration (Mo-Co-C3) is designed and synthesized, in which the carbon intercalation is utilized to regulate sulfur vacancies for anchoring the Co atom. The introduction of Co atoms and C intercalation significantly enhances the Eads between catalyst and peroxymonosulfate (PMS), favoring the formation of metastable intermediates. The kobs of sulfamethoxazole (SMX) removal for MoSO-Co-C is 9.2 times and 1.8 times higher than those of catalysts without Co or C intercalation. SMX is removed mainly by electron transfer pathway, wherein SMX and PMS act on the same Co site of MoSO-Co-C, and electrons are transferred from SMX to MoSO-Co-C and eventually to PMS. The MoSO-Co-C demonstrated excellent SMX degradation in the diverse water matrices, and the removal efficiency of SMX maintained above 95 % after 72 h of continuous degradation. This study provides new insights into the design of transition metal-based SAC and in-depth understanding of PMS activation mechanism.

Highly-separated Co anchored on S, O-doped carbon nitride for enhanced peroxymonosulfate activation: Insights into radical and non-radical pathways

Understanding the various catalytic mechanisms of activated peroxymonosulfate (PMS) is crucial for designing high-efficiency metal-supported catalysts. Herein, Co, S, O co-doped carbon nitride (CoCN-x) was constructed. Density functional theory (DFT) calculations for CN doped with different elements revealed that CoCN-x exhibited improved PMS activation capabilities. Optimized CoCN-0.5 achieved a 95% removal rate of sulfamethoxazole (SMX) within 30 s, with a degradation rate constant of 2.92 min−1, which is 845.34 times higher than that of the original CN. Additionally, the activation mechanism of PMS was thoroughly investigated, revealing the presence of classical radicals such as OH, SO4− and O2− and non-radicals involving 1O2, CoO2+, and electron transfer. Potential SMX degradation pathways were also elucidated using DFT calculations, HPLC-MS, and 3D EEMs. This work provides new insights into the development of catalysts that effectively activate PMS through both radical and non-radical mechanisms.

Highly selective regulation of non-radical and radical mechanisms by Co cubic assembly catalysts for peroxymonosulfate activation

Peroxymonosulfate (PMS) activation on efficient catalysts is a promising strategy to produce sulfate radical (SO4−) and singlet oxygen (1O2) for the degradation of refractory organic pollutants. It is a great challenge to selectively generate these two reactive oxygen species, and the regulation mechanism from non-radical to radical pathway and vice versa is not well established. Here, we report a strategy to regulate the activation mechanism of PMS for the selective generation of SO4− and 1O2 with 100 % efficiency by sulfur-doped cobalt cubic assembly catalysts that was derived from the Co-Co Prussian blue analog precursor. This catalyst showed superior catalytic performance in activating PMS with normalized reaction rate increased by 87 times that of the commercial Co3O4 nanoparticles and had much lower activation energy barrier for the degradation of organic pollutant (e.g., p-chlorophenol) (18.32 kJ⋅mol−1). Experimental and theoretical calculation results revealed that S doping can regulate the electronic structure of Co active centers, which alters the direction of electron transfer between catalyst and PMS. This catalyst showed a strong tolerance to common organic compounds and anions in water, wide environmental applicability, and performed well in different real-water systems. This study provides new opportunities for the development of metal catalyst with metal-organic frameworks structure and good self-regeneration ability geared specifically towards PMS-based advanced oxidation processes applied for water remediation.

Highly-efficient peroxymonosulfate activation by porous nano-MgO for tetracycline degradation: Surface hydroxyl groups and oxygen vacancies synergetic mediated nonradical process

Heterogeneous transition metal activation of peroxymonosulfate (PMS)-based advanced oxidation processes is limited by low cycling efficiency, secondary contamination, and high toxicity. In this study, a non-transition metal porous nano-MgO catalyst from natural dolomite was synthesized and PMS activation was performed to degrade tetracycline (TC). The nano-MgO/PMS system could achieve TC degradation of 88.09 % within 20 min under the optimum parameters (nano-MgO dosage of 0.2 g·L−1, PMS concentration of 0.3 mM), exceeding the efficiency of the PMS-alone system (11.66 %) by 7-fold, which was related to large specific surface area (41.19 m2·g−1) and defect structure of porous nano-MgO catalysts. As revealed by the quenching tests and electron paramagnetic resonance (EPR) analysis, different from transition metal activation PMS where radicals are generated, singlet oxygen (1O2) was essential in the nano-MgO/PMS oxidation process. Notably, the density functional theory (DFT) calculations demonstrated that nano-MgO with surface hydroxyl groups and oxygen vacancies exhibited the longer O-O bond length (1.47 Å), stronger adsorption energy of PMS (-4.07 eV), and faster electron transfer (0.91 e) than the only nano-MgO with surface hydroxyl groups, proving the surface hydroxyl groups and oxygen vacancies active sites in nano-MgO could synergistically mediate the PMS activation process. Furthermore, the proposed three TC degradation pathways and the toxicity evaluation of intermediates suggested that nano-MgO/PMS system have good ecological safety. This work offers an innovative approach for the cost-effective preparation of porous magnesium oxide with highly efficiency, offering a new perspective for understanding the PMS activation mechanism induced by non-transition metal.

Ferrocenedicarboxylate modified Bi-MOF for water decontamination via different advanced oxidation processes: Multifunction, mechanisms and biotoxicity test

Peroxymonosulfate (PMS), peroxydisulfate (PDS) and hydrogen peroxide (H2O2)-based advanced oxidation processes are extensively applied for aqueous pollutants degradation. However, few cases reported the comparison the PMS, PDS and H2O2 activation performances of a heterogeneous catalyst. In this work, 1,1′-ferrocenedicarboxylate (Fc) modified Bi-BDC (Bi-BDC-Fcx) with unique electronic structure and strong oxidation ability was synthesized and applied for degrading bisphenols (BPs) via photocatalytic PMS, PDS, and H2O2 activation, respectively. The optimum Bi-BDC-Fc0.1 exhibited the best photocatalytic PMS, PDS and H2O2 activation performance to degrade various organic pollutants, including BPs, in which the bisphenol A degradation efficiencies followed the order of Bi-BDC-Fc0.1/UVL/PMS, Bi-BDC-Fc0.1/UVL/PDS and Bi-BDC-Fc0.1/UVL/H2O2. The reaction mechanisms of photocatalytic PMS, PDS and H2O2 activation over Bi-BDC-Fc0.1 were comprehensively clarified by experimental results along with DFT calculations. Also, the toxicity and ecotoxicological impact of the pristine BPs and their intermediates were evaluated by the phytotoxicity experiments and zebrafish early-life stage toxicity test. This work presented a comprehensive investigation of degradation performance and the ecotoxicology assessment of Bi-BDC-Fcx/UVL/PMS, Bi-BDC-Fcx/UVL/PDS, and Bi-BDC-Fcx/UVL/H2O2 systems, providing valuable insights to design and utilize the newly developed catalysts for water purification.

Co and N co-doped carbon nanotubes catalyst for PMS activation: Role of non-radicals

Metal-nitrogen-carbon catalysts demonstrate significant advantages in the remediation of water environments. Here, a cobalt-nitrogen-carbon catalyst (Co(1.5)-NCNT) with abundant Co-Nx active sites and excellent electron transfer capability was prepared via a simple method and used to activate peroxymonosulfate (PMS) for efficient removal of Acetaminophen (APAP). As a result, the Co(1.5)-NCNT/PMS system removed 100% of APAP within 10 min. The reaction process characterization suggested that PMS is adsorbed by Co(1.5)-NCNT to form a Co(1.5)-NCNT-PMS complex, which accelerates PMS activation. Additionally, the singlet oxygen (1O2) generated by PMS activation can effectively attack electron-rich contaminants, facilitating the rapid degradation of APAP. Furthermore, Co(1.5)-NCNT/PMS exhibits strong environmental adaptability, maintaining high catalytic performance in complex water environments for the effective degradation of various pollutants. This study elucidates the properties of Co-Nx active sites in the Co(1.5)-NCNT/PMS system and the activation mechanism of PMS, providing new insights into the removal of pollutants through non-radical pathways.

Composition-dependent PMS activation in SrxLa2-xCoO4±δ perovskite-derivatives: From radical to strengthen the electron-transfer pathway

Ruddlesden-Popper phases (R-P) with the chemical formula SrxLa2-xCoO4±δ (x=0.6, 0.8, 1.0, 1.2, and 1.5), consisting of alternating layers of perovskite and rock-salt type oxides, were found to be efficient catalysts for peroxymonosulfate (PMS) activation. By modifying the strontium content, it is possible to tune the spin state of cobalt in the material, which in turn affects the PMS activation mechanism. When the rock-salt layer is intercalated in the R-P perovskite structure, as in Sr0.8La1.2CoO4, a non-radical pathway is involved, which exhibits superior performance in PMS activation, as indicated by the higher reaction rate constant (0.70 min−1) compared to LaCoO3 (0.13 min−1) with SO4•- generation as the primary mechanism. This research provides a deeper understanding of how the electronic structure of cobalt in perovskite oxides influences the PMS activation mechanism. Such insights are crucial for the rational design of effective PMS activators for water treatment.

Peroxymonosulfate activation by iron-cobalt bimetallic phosphide modified nickel foam for efficient dye degradation

Novel catalysts with multiple active sites and rapid separation are required to effectively activate peroxymonosulfate (PMS) for the removal of organic pollutants from water. Therefore, an integrated catalyst for PMS activation was developed by directly forming Co–Fe Prussian blue analogs on a three-dimensional porous nickel foam (NF), which were subsequently phosphorylated to obtain cobalt-iron bimetallic phosphide (FeCoP@NF). The FeCoP@NF/PMS system efficiently degraded dye wastewater within 20 min. The system exhibited excellent catalytic degradation over a broad pH range and at high dye concentrations due to the presence of unique asymmetrically charged Coa+ and Pb− dual active sites formed by cobalt phosphides within FeCoP@NF. These active sites significantly enhanced the catalytic activity of PMS. The activation mechanism of PMS involves phosphorylation that accelerates electron transfer from FeCoP@NF to PMS, to generate SO4·–, ·OH, O2·–, and 1O2 active species. Three-dimensional FeCoP@NF could be readily recycled and showed good stability for PMS activation. In this study, a highly efficient, stable, and readily recyclable integrated catalyst was developed. This catalyst system effectively resolves the separation and recovery issues associated with conventional powder catalysts and has a wide range of potential applications in wastewater treatment.

Boosted peroxymonosulfate activation by bimetallic organometallic frameworks via by-produced and dominated H2O2 generation

Verifying the role of H2O2 is a critical challenge for deepening the understanding of the mechanism of peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs). In this research, Co, Fe bimetallic organometallic frameworks (ZIF-L@Fe28) were prepared, and their ultrahigh activities via H2O2 generation at Fe and Co sites were experimentally and theoretically verified. The important contribution of H2O2 to 1O2 production was identified through the quantifications of the mutual transformation of active species. Co sites were identified as the most active positions for PMS activation because of they strongly triggered 1O2, SO4·−, ⋅O2−, ·OH, and H2O2. However, the self-quenching of active species suppressed the efficiency and selectivity of 1O2 generation at Co sites. In contrast to Co sites, Fe sites had selective preference for H2O2 generation, and the transformation of H2O2 to 1O2 further enhanced the performance of ZIF-L@Fe28. The supplementary discussion from the perspective of H2O2 will enable the further application of the PMS activation mechanism.

Visible-light-assisted peroxymonosulfate activation by metal-free g-C3N4 isotype heterojunction for water purification: Surface-activated complex and 1O2 dominated non-radical mechanisms

Visible-light-assisted peroxymonosulfate (PMS) activation is flourishing in wastewater decontamination, but exploiting safe and efficient activators remains challenging due to a deficient cognition of the activated mechanisms. Hereby, a metal-free g-C3N4 isotype heterojunction (HCN) was successfully synthesized and activated PMS under visible light. The Z-scheme isotype heterojunction significantly meliorated light absorption and carrier migration, thereby enhancing PMS activation. The optimal HCN + PMS system almost completely removed ranitidine (RAN) in 30 min with 7.46–8.48 times higher activity than the monomers. Through systematic experiments and characterizations, we proposed a non-radical mechanism of PMS activation, which generated predominated surface-activated complex and singlet oxygen (1O2) for pollutant removal. The surface-activated complex degraded RAN by drawing its electrons. This non-radical pathway exhibited tolerance towards background substances and pH fluctuations. Additionally, the broad-spectrum decontamination and recyclability of the system further enhanced its practical applicability. Notably, intermediate analyses confirmed the RAN degradation pathways predicted by theoretical calculations, with the resulting intermediates found to be non-toxic. This study significantly contributes to our understanding of the non-radical mechanisms of PMS activation on g-C3N4-based activators for micropollutant degradation.

Non-radical activation of peroxymonosulfate by modified activated carbon for efficient degradation of oxytetracycline: Mechanisms and applications

The application of heterogeneous metal-free catalysis for non-radical peroxymonosulfate (PMS) oxidation is of great significance because of its low environmental effects and mild oxidant dosage. The purpose of this study was to investigate the activation mechanism of PMS using acid-modified activated carbon and oxytetracycline (OTC) as a representative pollutant. Modified activated carbon (MAC)/PMS system was capable of achieving 100 % degradation efficiency of OTC within 60 min, with an observed rate constant (kobs) of 0.0414 min−1. The degradation of OTC is dominated by non-radical oxidation pathways involved in mediated singlet oxygen (1O2) and electron-transfer process through electron paramagnetic resonance (EPR) and radicals quenching studies. The activation of PMS is attributed to the structural defects of MAC, persistent free radicals, and oxygen functional groups such as C-OOH. Moreover, the MAC/PMS system consistently demonstrates high and reliable contaminant removal in various water matrices. A continuous-flow device utilizing MAC shows excellent performance in purifying micro-polluted water. Additionally, the degradation pathways of pollutants and changes in toxicity during the degradation process were identified through density functional theory (DFT) calculations, liquid chromatography-mass spectrometry (LC-MS), and toxicological analysis. Finally, the cultivation of green beans, peas, and wheat was found to significantly decrease the toxicity of contaminated water through degradation. This study proposes a low-cost method to enhance the activation pathway of non-radical PMS by utilizing modified activated carbon materials for pollutant remediation.

Salt assistant bimetallic sludge-derived porous carbon for efficient peroxymonosulfate activation

The development of cost-effective, environmentally benign, and high-performance peroxymonosulfate (PMS) activation towards wastewater treatment is still considered a challenge. In this work, the sludge-derived porous carbon loaded with bimetal oxides (DSC-FeMn) was fabricated by molten salt assistant strategy using the combination of zinc chloride, metal ions and Fe containing sludge. The obtained DSC-FeMn exhibited high catalytic activity for nearly 100 % 4-chlorophenol (4-CP) removal within 30 min with the k of 0.304 min−1, which was 1.07 and 11.94 times that of the single Fe and Mn-sludge-derived carbon (DSC-Fe, DSC-Mn), respectively. Quenching experiments, electron paramagnetic resonance tests (EPR), X-ray photoelectron spectroscopy (XPS), H2-temperature programmed reduction (H2-TPR) and electrochemical experiments proved that the radical pathway, dominated by OH and SO4−, led to the excellent degradation performance of DSC-FeMn, which was attributed to the redox cycling between Fe and Mn. This study provides a new idea for sludge resource utilization, and it deepens the understanding of the mechanism of PMS activation by the synergistic interaction between bimetal.

Anchored Cobalt Nanoparticles on Layered Perovskites for Rapid Peroxymonosulfate Activation in Antibiotic Degradation.

In the Fenton-like reaction, revealing the dynamic evolution of the active sites is crucial to achieve the activity improvement and stability of the catalyst. This study reports a perovskite oxide in which atomic (Co0) in situ embedded exsolution occurs during the high-temperature phase transition. This unique anchoring strategy significantly improves the Co3+/Co2+ cycling efficiency at the interface and inhibits metal leaching during peroxymonosulfate (PMS) activation. The Co@L-PBMC catalyst exhibits superior PMS activation ability and could achieve 99% degradation of tetracycline within 5min. The combination of experimental characterization and density functional theory (DFT) calculations elucidates that the electron-deficient oxygen vacancy accepts an electron from the Co 3d-orbital, resulting in a significant electron delocalization of the Co site, thereby facilitating the adsorption of the *HSO5/*OH intermediate onto the "metal-VO bridge" structure. This work provides insights into the PMS activation mechanism at the atomic level, which will guide the rational design of next-generation catalysts for environmental remediation.

Sulfur and chloride co-doped g-C3N4 in photocatalytic peroxymonosulfate activation for enhanced acetaminophen removal: Combination of experiments and DFT calculations

As a green photocatalyst with simple synthesis method, excellent electronic structure, and metal-free properties, the deficiencies of pristine graphitic carbon nitride, such as high electron transfer resistance and narrow energy band gap, inhibit its photocatalytic activity to some extent. In this paper, we synthesized a sulfur and chlorine co-doped g-C3N4 (SCl-CN) capable of efficient photocatalytic activation of peroxymonosulfate (PMS) by calcining a mixture of ammonium chloride and thiourea. By means of DFT calculation, the contribution of sulfur and chlorine to photogenic electron hole separation was discussed. The electrostatic potential of SCl-CN and the adsorption model between SCl-CN and PMS were deduced, and the activation mechanism of PMS was further analyzed. According to the calculated results, the incorporation of sulfur and chlorine tuned the electronic configuration of the material and intensified the interactions between SCl-CN and PMS. It is shown that free and non-free radicals act simultaneously in the SCl-CN/PMS/Vis system. This study provides a new idea for the study of photocatalytic activation of PMS by non-metallic co-doped carbon nitride.

LaCoO3/SBA-15 as a high surface area catalyst to activate peroxymonosulfate for degrading atrazine in water

An efficient perovskite-based heterogeneous catalyst is highly desired to activate peroxymonosulfate (PMS) for removing organic pollutants in water. A high surface area PMS-activator was fabricated by loading LaCoO3 on SBA-15 to degrade atrazine (ATR) in water. The LaCoO3/SBA-15 depicted better textural properties and higher catalytic activity than LaCoO3. In 6.0 min, atrazine (ATZ) degradation in the selected LaCoO3/SBA-15/PMS system, LaCoO3, adsorption by LaCoO3/SBA-15, sole PMS processes reached approximately 100%, 55.15%, 12.80%, and 16.65 % respectively. Furthermore, 0.04 mg L−1 Co was leached from LaCoO3/SBA-15 during PMS activation by LaCoO3/SBA-15. The LaCoO3/SBA-15 showed stable catalytic activity after reuse. The use of radical scavengers and electron paramagnetic resonance spectroscopy (EPR) demonstrated that ROS such as 1O2, O2•−, •OH, and SO4•− were generated by PMS activated by LaCoO3/SBA-15 owing to redox reactions [Co2+/Co3+, and O2−/O2]. EPR, XPS, ATR-FTIR, EIS, LSV, and chronoamperometric measurements were used to explain the catalytic mechanism for PMS activation. Excellent atrazine degradation was due to high surface area, porous nature, diffusion-friendly structure, and ROS. Our investigation proposes that perovskites with different A and B metals and modified perovskites can be loaded on high surface area materials to activate PMS into ROS.

Fe doping strategy induces peroxymonosulfate activation by ZIF-67 through a non-radical reaction pathway with dominant 1O2 generation

Zeolitic Imidazole Framework-67 (ZIF-67), which can be large-scale synthesized under mild conditions, has been widely reported as a promising and efficient catalyst in peroxymonosulfate (PMS)-based advanced oxidation process. However, ZIF-67 typically activates PMS through a monotonous free radical reaction pathway, which limits its reusability, resistance to environmental interference, and degradation selectivity. In this study, controlled doping of Fe atoms into the lattice structure of ZIF-67 (FexCo1-x-ZIF) was employed, resulting in the nearly complete conversion of PMS to 1O2 through a unique non-radical pathway. Series of experiments, characterizations, and theoretical calculations were employed to elucidate the micro-level mechanism of PMS activation. The results indicate that the tetrahedral coordinated Co-N4 sites in ZIF-67 are transformed into unsaturated Co-N2 sites due to the competitive coordination effect upon the introduction of Fe. PMS adsorption is enhanced as both oxygen atoms bind simultaneously to the Co-N2 site, inducing the removal of a hydrogen atom from PMS and electron transfer from PMS to the Co-N2 site, thus facilitating the generation of 1O2. The 1O2-dominated non-radical degradation reaction enhances the excellent degradation performance, reusability, and environmental tolerance of the FexCo1-x-ZIF/PMS system under diverse natural water conditions, presenting significant prospects for practical applications.