Heterogeneous activation of peroxymonosulfate by cobalt-doped MIL-53(Al) for efficient tetracycline degradation in water: Coexistence of radical and non-radical reactions

Selective oxidation behavior based on iron-doped MOF derived carbon-based catalysts: Active site regulation and degradation mechanism analysis

Selective removal of target organic pollutants in complex water quality of municipal sewage is extremely important for the deep treatment of water quality. Here, energetic MOF and Fe-MOF are doped in electrostatic spinning process to adjust the structure and composition of the catalysts, active oxygen species (ROSs), realizing the selective removal of organic pollutants. Non-azo and azo pollutants are selected as target pollutants. Catalysts PCFe-8 with Fe nanoclusters, EPCFe-8 with Fe-Nx, and EPC-8 without Fe doping are used to activate peroxymonosulfate (PMS) for degrading pollutants. The results show that the PCFe-8/PMS system can produce the most SO4- and exhibit superior removal of azo pollutants, whereas the degradation behavior of non-azo pollutants is more inclined to occur in the EPCFe-8/PMS system and the EPC-8/PMS system. This work provides a reference for elucidating the relationship between catalyst structure and components, types of ROSs, and selective degradation of pollutants.

A new strategy to construct MOF-on-MOF derivatives for the removal of tetracycline hydrochloride from water by activation of peroxymonosulfate

A MOF-on-MOF composite derivative material named ZIF-67@Ce-MOF-600 was designed and synthesized. The preparation of ZIF-67@Ce-MOF-600 was optimized from the aspects of the ratio of metal and ligand, heat-treatment temperature. It was demonstrated by XRD, FT-IR, SEM-EDS and TEM. The optimum conditions for the activation of PMS by ZIF-67@Ce-MOF-600 for the degradation of tetracycline (TC) were investigated by adjusting the catalyst dosage, TC, pH, peoxymonosulfate (PMS) concentration, and different kinds of water, co-existing anions and pollution. Under optimal conditions (20 mg catalysts and 50 mg PMS added) in 100 mL of tetracyclines (TC) solvent (20 mg TC/L), the removal rate could reach up to 99.2% and after five cycles was 70.5%. The EPR results indicated the presence of free radicals and non-free radical, among which free radicals intended to play a major role in the degradation process. Its possible degradation pathways and attack sites were analyzed by liquid-phase mass spectrometry and DFT analysis.

Tackling antibiotic contaminations in wastewater with novel Modified-MOF nanostructures: A study of molecular simulations and DFT calculations

The contamination of wastewater with antibiotics has emerged as a critical global challenge, with profound implications for environmental integrity and human well-being. Adsorption techniques have been meticulously investigated and developed to mitigate and alleviate their effects. In this study, we have investigated the adsorption behaviour of Erythromycin (ERY), Gentamicin (GEN), Levofloxacin (LEVO), and Metronidazole (MET) antibiotics as pharmaceutical contaminants (PHCs) on amide-functionalized (RC (=O)NH2)/MIL-53 (Al) (AMD/ML53A), using molecular simulations and density functional theory (DFT) calculations. Based on our DFT calculations, it becomes apparent that the adsorption tendencies of antibiotics are predominantly governed by the presence of AMD functional groups on the adsorbent surface. Specifically, hydrogen bonding (HB) and van der Waals (vdW) interactions between antibiotics and AMD groups serve as the primary mechanisms facilitating adsorption. Furthermore, we have observed that the adsorption behaviors of these antibiotics are influenced by their respective functional groups, molecular shapes, and sizes. Our molecular simulations delved into how the AMD/ML53A surfaces interact with antibiotics as PHCs. Moreover, various chemical quantum descriptors based on Frontier Molecular Orbitals (FMO) were explored to elucidate the extent of AMD/ML53A adsorption and to assess potential alterations in their electronic properties throughout the adsorption process. Monte Carlo simulation showed that ERY molecules adsorb stronger to the adsorbent in acidic and basic conditions than other contaminants, with high energies: -404.47 kcal/mol in acidic and -6375.26 kcal/mol in basic environments. Molecular dynamics (MD) simulations revealed parallel orientation for the ERY molecule's adsorption on AMD/ML53A with 80% rejection rate. In conclusion, our study highlighted the importance of modeling in developing practical solutions for removing antibiotics as PHCs from wastewater. The insights gained from our calculations can facilitate the design of more effective adsorption materials, ultimately leading to a more hygienic and sustainable ecosystem.

Promoting oxygen vacancies utility for tetracycline degradation via peroxymonosulfate activation by reduced Mg-doped Co3O4: Kinetics and key role of electron transfer pathway

Developing cobalt-based catalysts with a high abundance of oxygen vacancies (Vo) and exceptional Vo utility efficiency for the prompt removal of stubborn contaminants through peroxymonosulfate (PMS) activation poses a significant challenge. Herein, we reported the synthesis of the reduced Mg-doped Co3O4 nanosheets, i.e. Mg-doped Co3O4-r, via Mg doping and followed by NaBH4 reduction, aiming to degrade tetracycline (TC). Various characterization results illustrated that NaBH4 reduction imparted higher Vo utility efficiency to Mg-doped Co3O4-r, along with an ample presence of reduced Co2+ species and an increased surface area, thereby substantially elevating PMS activation capability. Notably, Mg-doped Co3O4-r achieved more than 97.9% degradation of 20 mg/L TC within 10 min, showing an over 8-fold increase in reaction rate relative to the Mg-doped Co3O4 (kobs: 0.3285 min-1 vs 0.0399 min-1). The high removal efficiency of TC was sustained across a broad pH range of 3-11, even in the presence of common anions and humic acid. Radical quenching trials, EPR outcomes, and electrochemical analysis indicated that neither radicals nor 1O2 were the primary active species. Instead, electron transfer pathway played a dominant role in TC degradation. The Mg-doped Co3O4-r displayed excellent recyclability and versatility. Even after the fifth cycle, it maintained an impressive 83.0% removal of TC. Furthermore, it exhibited rapid degradation capabilities for various pollutants, including levofloxacin, pefloxacin, ciprofloxacin, malachite green, and rhodamine B. The TC degradation pathway was proposed based on LC-MS determination of its degradation intermediates. This study showcases an innovative strategy for the rational design of an efficient cobalt-based activator, leveraging electron transfer pathways through PMS activation to degrade antibiotics effectively.

Cerium oxide /Co-Co Prussian blue analogue composite catalyst for enhanced peroxymonosulfate activation for effective removal of tetracycline hydrochloride from water

In this paper, a novel CeO2/Co3[Co(CN)6]2 (CeO2/PBACo-Co) composite was prepared with co-precipitation and utilized to activate peroxymonosulfate (PMS) to eliminate tetracycline hydrochloride (TCH). Catalyst screening showed that the composite with a CeO2:PBACo-Co mass ratio of 1:5 (namely, 0.2-CeO2/PBACo-Co) had the best performance. The degradation efficiency of TCH in 0.2-CeO2/PBACo-Co/Oxone system was investigated. The experimental results illustrated that 98% of 50 mg/L TCH and 48.5% of TOC were degraded by 50 mg/L 0.2-CeO2/PBACo-Co and 400 mg/L Oxone within 120 min at 25 °C and initial pH 5.3. Recycling studies showed that the elimination rate of TCH can still achieve 85.8% after five cycles, suggesting that 0.2-CeO2/PBACo-Co composite processes good reusability. Trapping experiments and EPR tests revealed that the reaction system produced multiple active species (1O2, O2•-, SO4•-, and •OH). We proposed the catalytic mechanism of 0.2-CeO2/PBACo-Co for PMS activation, which mainly involves the promoted Co3+/Co2+ cycle by Ce3+ donated electrons. These results indicate that CeO2/PBACo-Co composite is an effective catalyst for wastewater remediation.

In situ synthesis of oxygen-doped carbon quantum dots embedded in MIL-53(Fe) for efficient degradation of oxytetracycline

Introducing carbon quantum dots (CQDs) into photocatalysts is believed to boost the charge transfer rate and reduce charge complexation. Doping heteroatoms such as N, S, or P enable CQDs to have an uplifting electron transfer capability. However, the application of oxygen-doped CQDs to improve the performance of photocatalysts has rarely been reported. Herein, a type of carbon-oxygen quantum dots (COQDs) was in situ embedded into MIL-53(Fe) to aid peroxydisulfate (PDS)-activated degradation of oxytetracycline (OTC) under visible light irradiation. The successful embedding of COQDs was confirmed by XRD, FT-IR, XPS, SEM, and TEM techniques. Photoelectrochemical testing confirmed its better performance. The prepared COQDs1/MIL-53(Fe) showed 88.2% decomposition efficiency of OTC in 60 min, which was 1.45 times higher than that of pure MIL-53(Fe). In addition, the performance of the material was tested at different pH, OTC concentrations, catalyst dosing, and PDS dosing. It was also subjected to cyclic testing to check stability. Moreover, free radical trapping experiments and electron paramagnetic resonance were conducted to explore the possible OTC deterioration mechanism. Our work provides a new idea for the development of MOFs for water treatment and remediation.

Chitosan derived N-doped carbon anchored Co3O4-doped MoS2 nanosheets as an efficient peroxymonosulfate activator for degradation of dyes

Peroxymonosulfate (PMS), which is dominated by non-free radical pathway, has a good removal effect on organic pollutants in complex water matrices. In this article, a biodegradable cobalt-based catalyst (Co3O4/MoS2@NCS) was synthesized by a simple hydrothermal method with chitosan (CS) as nitrogen‑carbon precursor and doped with Cobaltic‑cobaltous oxide (Co3O4) and Molybdenum disulfide (MoS2), and was used to activate PMS to degrade dye wastewater. Electrochemical tests showed that Co3O4/MoS2@NCS exhibited higher current density and cycling area than MoS2@NCS and MoS2. In the Co3O4/MoS2@NCS/PMS system, the degradation rate of 30 mg·L-1 rhodamine B (RhB) reached 97.75 % within 5 min, and kept as high as 94.34 % after 5 cycles. Its rate constant was 1.91 and 8.37 times that of MoS2@NCS/PMS and MoS2/PMS, respectively. It had good complex background matrices and acid-base anti-interference ability, and had good universality and reusability. The degradation rate of methyl orange (MO) and methylene blue (MB) were more than 91 % within 5 min at pH 4.8. The experimental results demonstrated that MoS2-modified CS as a carrier exposed a large number of active sites, which not only dispersed Co3O4 nanoparticles and improved the stability of the catalyst, but also provided abundant electron rich groups, and promoted the activation of PMS and the production of reactive oxygen species (ROS). PMS was effectively activated by catalytic sites (Co3+/Co2+, Mo4+/Mo5+/Mo6+, CO, pyridine N, pyrrole N, hydroxyl group and unsaturated sulfur), producing a large number of radicals that attack RhB molecules, causing chromophore cleavage, ring opening, and mineralization. Among them, non-free radical 1O2 was the main ROS for RhB degradation. This work is expected to provide a new idea for the design and synthesis of environmentally friendly and efficient MoS2-modified cobalt-based catalysts.

The correlation between electron exchange capacity of Fenton-like heterogeneous catalyst and catalytic activity

Electron transfer played key role in peroxymonosulfate (PMS) activation for heterogeneous Fenton-like catalysts (HFCs). However, the relationship between electron exchange capacity (EEC) and catalytic activity of HFCs has not been elucidated. Herein, thirteen HFCs reported in our previous studies were selected to measure their EEC via electrochemical methods and to investigate the correlation between EEC and catalytic activity for PMS. The results show that nitrogen-doped graphene oxide had much higher EEC (5.299 mM(e) g-1), followed by reduced graphene oxide (3.23 mM(e) g-1), nitrogen-doped biochar-700 (2.032 mM(e) g-1), graphene oxdie (1.789 mM(e) g-1), nitrogen-doped biochar-300 (1.15 mM(e) g-1), g-C3N4 (0.752 mM(e) g-1) and biochar (0.351 mM(e) g-1). For carbon materials, their catalytic activity was not determined by electron donor capacity (EDC), electron acceptor capacity (EAC) and EEC (EDC + EAC), but was linear correlation with |EDC-EAC| that can characterize the extent of HFCs reacting with PMS. The higher the |EDC-EAC| is, the higher the catalytic activity of HFCs is. For carbonaceous materials, their catalytic activity was not proportional to EAC, but had good linear correlation with EDC and |EDC-EAC|. The discrepancy between carbon materials and carbonaceous materials could be due to the different activation mechanisms. Further analysis found that there was no correlation between EEC and the reactive species derived from PMS, indicating that the produced reactive species was not only controlled by EEC. This study firstly elucidated the correlation between EEC and catalytic activity of HFCs, and |EDC-EAC| could be used as an index for evaluating the catalytic activity of HFCs.

From waste to catalyst: Growth mechanisms of ZSM-5 zeolite from coal fly ash & rice husk ash and its performance as catalyst for tetracycline degradation in fenton-like oxidation

Coal fly ash (CFA), an industrial solid waste, can be utilized to synthesize Zeolite Socony Mobil-5 (ZSM-5) by incorporating an external silica source. In this study, a series of ZSM-5 zeolites were synthesized using rice husk ash (RHA) as the primary silica source and CFA as the primary aluminum source under controlled hydrothermal reaction conditions, and the growth mechanism of ZSM-5 was investigated. The process of ZSM-5 growth was featured by the transformation of hyperpoly silico-aluminate in CFA and RHA into monomers. These monomers formed crystal nuclei connected in a five-membered ring structure under the influence of Tetrapropyl ammonium hydroxide (TPAOH). The surplus monomeric silica-aluminate grew on the nucleus surface due to the addition of the silica source within RHA (RHA-SiO2), ultimately resulting in the development of ZSM-5 zeolite. Characterization results demonstrated that RHA-SiO2 exhibited favorable physical and chemical properties during the ZSM-5 synthesis, with a crystallinity of 99.03%, a specific surface area of 321.19 m2/g, a weight loss of only 3.06% at 800 °C and a total acidity of 0.65 mmol/g. To evaluate the catalytic performance of ZSM-5, Fe/Cu-modified ZSM-5 was developed and used as the catalyst for the degradation of tetracycline (TC) in Fenton-like oxidation. The results indicated that Fe/Cu-ZSM-5 exhibited excellent activity and stability as the catalyst for TC degradation and mineralization. The maximum TC degradation rate reached 99.02% in 10 min and the TOC removal could be up to 69.32% in 2 h. Characterization results indicated that the Fe/Cu ions redox cycle accelerated the generation of active species (1O2 and ˙OH) in Fenton-like systems. The ZSM-5 zeolite synthesized from solid waste demonstrated superb stability and catalytic activity, leading to the effective removal of TC. Since real wastewater generally contains various pollutants, future research efforts should focused on multi-pollutant treatment.

Development of hybrid MIL-53(Al)@CBS for ternary adsorption of tetracyclines antibiotics in water: Physical interpretation of the adsorption mechanism

In this study, a hybrid material, MIL-53(Al)@CBS, was synthesized via the solvothermal method, involving the growth of MIL-53(Al) crystals on cocoa bean shell residues (CBS). Physicochemical characterization techniques, including TGA, BET, FTIR, XRD, and SEM, confirmed successful hybridization. MIL-53(Al)@CBS was employed as an adsorbent for antibiotics (oxytetracycline, tetracycline, chlortetracycline) separation from aqueous solutions. Parameters like pH, adsorbent dose, concentration, time, and temperature were systematically evaluated. FTIR revealed π-π interactions and hydrogen bonds between tetracyclines and the adsorbent. MIL-53(Al)@CBS exhibited adsorption, with removal rates up to 98.92%, 99.04%, and 98.24% for OTC, TC, and CTC, respectively. Kinetics suggested adsorption depends on active site availability, with TC adsorbing fastest. Microscopic models showed adsorption on three distinct active site types with different affinities without competition or adherence to the Langmuir hypothesis. Importantly, MIL-53(Al)@CBS maintained high adsorption capacity even after ten washing cycles, highlighting its potential for water treatment.

Highly efficient removal of tetracyclines from water by a superelastic MOF-based aerogel: Mechanism quantitative analysis and dynamic adsorption

Metal-organic frameworks (MOFs) were promising adsorbents for removing antibiotics, but the inherent poor recyclability of MOF powders limits further application. Moreover, the dominant adsorption mechanisms and their quantitative assessment are less studied. Here, ultrahigh adsorption capacities of 821.51 and 931.87 mg g-1 for tetracycline (TC) and oxytetracycline (OTC), respectively, were realised by a novel adsorbents (biochar loaded with MIL-88B(Fe), denoted as BC@MIL-88B(Fe)), which were further immobilised in a 3D porous gelatin (GA) substrate. The obtained BCM/GA200 showed superior adsorption performance under wide pH ranges and under the interference of humic acid. Moreover, it can survive >8 cycles and even maintain high adsorption efficiency in different actual water samples. Notably, BCM/GA200 can selectively remove tetracyclines in a multivariate system containing other kinds of antibiotics and from a dynamic adsorption system. Most importantly, the results of X-ray photoelectron spectroscopy, 2D Fourier transform infrared correlation spectroscopy (2D-FTIR-COS) and density functional theory techniques revealed that (1) for TC adsorption, at pH < 4.0, the contribution of complexation was 25 %-45 %, whereas pore filling and hydrogen bonding accounted for 39 %-72 % of the total uptake. At 4.0 < pH < 10.0, the contribution of complexation increased to 60 %-82 %, whereas electrostatic attraction and π-π interaction were 4 %-13 % and 2 %-10 %, respectively. (2) For OTC adsorption, complexation was dominant at 3.0 < pH < 10.0, accounting for 55 %-86 % of the total uptake, and electrostatic attraction and π-π interactions caused 3 %-10 % and 3 %-15 %, respectively. (3) At pH > 10.0, pore filling dominated TC and OTC adsorption. Finally, the reaction sequences of the main adsorption mechanisms were also probed by 2D-FTIR-COS. This work solves the poor recyclability of MOF powders and provides a mechanistic insight into antibiotic removal by MOFs.

Domain-limited thermal transformation preparation of novel graphitized carbon-supported layered double oxides for efficient tetracycline degradation

The resource utilization of industrial lignin to construct high-performance catalysts for wastewater treatment field is pioneering research. Herein, the novel graphitized carbon-supported CuCoAl-layered double oxides (LDOs-GC) were successfully designed by the domain-limited thermal transformation technology using sodium lignosulfonate (LS) self-assembled CuCoAl-layered double hydroxides as the precursor. The optimized LDOs-GC catalyst owned the excellent tetracycline (TC) degradation of 98.0% within 15 min by activated peroxymonosulfate (PMS) under optimal conditions (20 mg/L catalyst, 1.5 mM PMS, 30 mg/L TC). The density of metal ions in the catalyst and the synergistic interaction between graphitized carbon (GC) and metal ions played a major role in TC degradation. Based on a comprehensive analysis, the TC degradation in LDOs-GC/PMS system was proved to be accomplished by a combination of free radicals (SO4·- and HO·) and non-radicals (1O2). Meanwhile, the possible degradation pathways of TC were proposed by the analysis of TC degradation intermediates and a comprehensive analysis of the rational reaction mechanism for TC degradation by LDOs-GC/PMS system was also performed. This work provides a new strategy for developing novel high-performance catalysts from industrial waste, while offering a green, cheap and sustainable approach to antibiotic degradation.

Electrochemically enhanced activation of Co3O4/TiO2 nanotube array anode for persulfate toward high catalytic activity, low energy consumption, and long lifespan performance

Advanced oxidation processes (AOPs) can directly degrade and mineralize organic pollutants (OPs) in water by generating reactive oxygen species with strong oxidizing ability. The development of advanced electrode materials with high catalytic performance, low energy consumption, no secondary pollution, and long lifespan has become a challenge that must be addressed in this field. A heterojunction catalyst loaded with Co3O4 on TDNAs (Co3O4/RTDNAs) was designed and constructed by a simple and efficient pyrolysis (Co3O4/TDNAs) and electrochemical reduction. Co3O4 can be uniformly distributed on the inner wall and surface of the TiO2 nanotubes, enhancing the specific surface area while forming a tight conductive interface with TiO2. This facilitates rapid transmission of electrons, thereby assisting Co3O4 in quickly activating PS to form reactive oxygen species. The Ti3+ and Ov generated in Co3O4/RTDNAs can significantly improve the electrocatalytic degradation of OPs. Also, the interface formed by Co3O4 and RTDNAs will effectively suppress Co2+ leakage, thereby reducing the risk of secondary pollution. When the reaction conditions were 1 mM PMS (PDS) and a current density of 5 mA/cm2 in the EA-PMS (PDS)/Co3O4/RTDNA system, 30 mg/L TC can achieve 83.24 % (81.89 %) removal in 120 min, with very low cobalt ion leaching, while the energy consumption was reduced significantly. Therefore, EA-PS/Co3O4/RTDNA system has strong stability and a high potential for treating the OPs in AOPs.

Role of Interface of Metal-Organic Frameworks and Their Composites in Persulfate-Based Advanced Oxidation Process for Water Purification

The persulfate activation-based advanced oxidation process (PS-AOP) is an important technology in wastewater purification. Using metal-organic frameworks (MOFs) as heterogeneous catalysts in the PS-AOP showed good application potential. Considering the intrinsic advantages and disadvantages of MOF materials, combining MOFs with other functional materials has also shown excellent PS activation performance and even achieves certain functional expansion. This Review introduces the classification of MOFs and MOF-based composites and the latest progress of their application in PS-AOP systems. The relevant activation/degradation mechanisms are summarized and discussed. Moreover, the importance of catalyst-related interfacial interaction for developing and optimizing advanced oxidation systems is emphasized. Then, the interference behavior of environmental parameters on the interfacial reaction is analyzed. Specifically, the initial solution pH and coexisting inorganic anions may hinder the interfacial reaction process via the consumption of reactive oxygen species, affecting the activation/degradation process. This Review aims to explore and summarize the interfacial mechanism of MOF-based catalysts in the activation of PS. Hopefully, it will inspire researchers to develop new AOP strategies with more application prospects.

Removal of oxytetracycline from water by S-doped MIL-53(Fe): Synergistic effect of surface adsorption and persulfate activation

In this study, a novel catalyst based on MIL-53(Fe) was synthesized and modified through sublimed sulfur (S-MIL-53(Fe)) to induce a synergistic effect of surface adsorption and persulfate activation. The S-doped modification not only increased the surface area but also accelerated the electron transfer process of the iron cycle. The performance of the newly synthesized S-MIL-53(Fe) adsorptive catalyst was evaluated by chemical adsorption and peroxydisulfate (PDS) activated removal of an emerging pollutants, oxytetracycline (OTC). The S-MIL-53(Fe) adsorptive catalyst was able to adsorb 61.7% of OTC after 120 min, and the removal efficiency reached 84.8% within 5 min after PDS dosing. The boosting effect of sulfur on the system was confirmed by characterization analysis and experimental testing. Even after 7 cycles, the removal efficiency of S-MIL-53(Fe) (69.0%) for OTC remained superior to that of pure MIL-53(Fe) (25.1%). Additionally, the adsorption kinetics and adsorption isotherm model of the material were investigated. The possible OTC degrading process was proposed based on radical quenching and electron paramagnetic resonance (EPR). This study provides a feasible way to fabricate an S-doped MIL-53(Fe) adsorptive catalyst for the remediation of antibiotics-containing wastewater.

Alginate@ZnCO2O4 for efficient peroxymonosulfate activation towards effective rhodamine B degradation: optimization using response surface methodology

A facile chemical procedure was utilized to produce an effective peroxy-monosulfate (PMS) activator, namely ZnCo₂O₄/alginate. To enhance the degradation efficiency of Rhodamine B (RhB), a novel response surface methodology (RSM) based on the Box-Behnken Design (BBD) method was employed. Physical and chemical properties of each catalyst (ZnCo₂O₄ and ZnCo₂O₄/alginate) were characterized using several techniques, such as FTIR, TGA, XRD, SEM, and TEM. By employing BBD-RSM with a quadratic statistical model and ANOVA analysis, the optimal conditions for RhB decomposition were mathematically determined, based on four parameters including catalyst dose, PMS dose, RhB concentration, and reaction time. The optimal conditions were achieved at a PMS dose of 1 g l^-1, a catalyst dose of 1 g l^-1, a dye concentration of 25 mg l^-1, and a time of 40 min, with a RhB decomposition efficacy of 98%. The ZnCo₂O₄/alginate catalyst displayed remarkable stability and reusability, as demonstrated by recycling tests. Additionally, quenching tests confirmed that SO₄˙^-/OH˙ radicals played a crucial role in the RhB decomposition process.

Fe-N co-doped coral-like hollow carbon shell toward boosting peroxymonosulfate activation for efficient degradation of tetracycline: Singlet oxygen-dominated non-radical pathway

Fe-N co-doped coral-like hollow carbon shell (Fe-N-CS) was synthesized via a simply impregnation-pyrolysis method. The Fe-N-CS showed an excellent ability for activating peroxymonosulfate (PMS), which could degrade about 93.74% tetracycline (20 mg/L) in 12 min. The Fe-N-CS/PMS system exhibited a good anti-interference capacity of various pH, inorganic anions, HA and different water qualities. More importantly, the Fe nanoparticles were anchored uniformly in the carbon layer, effectively limiting the metal leaching. The quenching tests and electron spin resonance (ESR) manifested that non-radical singlet oxygen (¹O₂) was the main reactive oxygen species (ROS) for TC degradation. The mechanism study showed that Fe nanoparticles, defect and graphite N played a key role in activating PMS to produce ROS. Moreover, three probable degradation pathways were proposed by using LC-MS measurements. Generally, this work had a new insight for the synthesis of heterogeneous Fe-N-C catalysts in the advanced oxidation process based on PMS.

Regeneration of methylene blue-saturated biochar by synergistic effect of H2O2 desorption and peroxymonosulfate degradation

Biochar, as an adsorbent, is widely used for the removal of organic pollutants in water body. Hence, after saturated adsorption, regeneration treatment is required to recover the adsorption performance of biochar. In this study, a biochar (P-GBC) prepared by phosphoric acid activation showed high adsorption capacity for methylene blue (MB) with the maximum adsorption capacity (Q_m) of 599.66 mg/g. Then, regeneration treatments using 4 mM peroxymonosulfate (PMS), 0.2 M hydrogen peroxide (H₂O₂) and their mixture were used to regenerate MB-saturated biochar with regeneration efficiencies of 58.24%, 66.01% and 94.88%, respectively. Combining with degradation and quenching experiments, it is found that synergistic effect of H₂O₂ desorption and PMS degradation is responsible for the enhancement of regeneration efficiency of P-GBC in H₂O₂-PMS system and enables a high mineralization rate of 82.68% for the MB adsorbed on P-GBC. Furthermore, EPR tests indicate that singlet oxygen (¹O₂) is assigned as the primary activate species for the degradation of MB and XPS analyses confirm that graphite nitrogen and carbonyl on P-GBC are the main active sites for the activation of PMS. Compared with conventional regenerants, H₂O₂-PMS system has the advantages of low dosage, high mineralization efficiency, and easy accessibility, and is also effective, sustainable and environmentally friendly for the regeneration of organic pollutants-saturated biochar.

Enhanced activation of peroxymonosulfate by a floating FeMo3Ox/C3N4 photocatalyst under visible-light assistance for oxytetracycline degradation: Performance, mechanisms and comparison with H2O2 activation

In this study, a floating FeMo₃O_x/C₃N₄-EP (FM-C-P) composite with highly stability and reusability was synthesized by an impregnation/calcination process and used to activate peroxymonosulfate (PMS) for oxytetracycline (OTC) degradation under visible light irradiation. The results demonstrated that 98.1% of OTC (50 mg/L) removal can be achieved by the activation of PMS (5 mM) using FM-C-P (1 g/L) in 30 min under visible light irradiation. The pseudo-first-order rate constant was calculated to be 0.181 min^-1. The degradation process with PMS was hardly affected by pH (3-11) and co-existing substance. ·SO₄^-, ·OH, ·O₂^- and ¹O₂ were produced in the Vis/PMS/FM-C-P system and ¹O₂ was determined to be the main reactive oxygen species (ROSs). The high efficiency of ROSs production mainly contributed to two mechanisms. Firstly, via the combination of ≡Fe (II)-·SO₅^- and free state ·SO₅^-, ¹O₂ could be generated on the Fe-N_x site. Secondly, photo-induced electrons in the FeMo₃O_x/g-C₃N₄ heterojunction could react with Fe (III) and Mo (VI) to form catalytically active species Fe (II) and Mo (IV). Moreover, the proposed degradation pathway and the toxicity of intermediated products was analyzed. Overall, this study was expected to deepen the understanding of the photo-assisted PMS activation and the generation of ¹O₂ with the presence of metal-oxide/C₃N₄ heterojunction.

Synthesis of bimetal MOFs for rapid removal of doxorubicin in water by advanced oxidation method

Doxorubicin (DOX) has been an emerging environmental pollutant due to its significant genotoxicity to mankind. Advanced oxidation processes are a potential strategy to remove DOX in water solution. To develop a highly efficient catalytic agent to remove DOX, bimetal MOFs were synthesized, with Cu²⁺ and Co²⁺ as the central ions and adenine as the organic ligand. This study investigated the degradation of DOX by Co/Cu-MOFs combined with peroxymonosulfate (PMS). It was found that the degradation of DOX by Co/Cu-MOFs can reach 80% in only 10 seconds. This can be explained by the charge transfer from Co(iii) to Co(ii) being accelerated by Cu²⁺, resulting in the rapid generation of free radicals, which was proved by the EIS Nyquist diagram. Co/Cu-MOFs can be reused by simply washing with water without inactivation. Therefore, Co/Cu-MOFs can be used as an efficient catalytic agent to degrade DOX in environmental water.

A dual purpose aluminum-based metal organic framework for the removal of chloramphenicol from wastewater

The presence of antibiotics in the aquatic environment can cause significant environmental and human health problems even at trace concentrations. Conventional treatment systems alone are ineffective in removing these resistant antibiotics. To address this problem, oxidation and adsorption techniques were used to explore the removal of recalcitrant antibiotic chloramphenicol (CAP). An aluminum-based metal-organic framework (Al-MIL) with high surface area and extended porosity, was prepared and used both as adsorbent and catalyst for the oxidation of CAP. Characterization of the Al-MIL revealed a large surface area of 1137 m² g^-1, a homogeneous microporous structure, good crystallinity, and particle size in the range of 200-400 nm. Adsorption of CAP on Al-MIL achieved equilibrium after 1 h, reaching a maximum adsorption capacity of 96.1 mg g^-1 at the optimum pH value of 5.3. The combination of adsorption and oxidation did not improve the % TOC reduction considerably, indicating an antagonistic rather than synergistic effect between the two processes. Oxidation alone in the presence of persulfate, achieved a % TOC reduction of 71% after 2 h, compared to 56% achieved by adsorption alone at the same duration. The optimum persulfate concentration was determined as 2.5 mM. The Al-MIL structure did not demonstrate any substantial deterioriation after six repeated runs, according to the reusability experiments.

Synthesis of mesoporous-structured MIL-68(Al)/MCM-41-NH2 for methyl orange adsorption: Optimization and Selectivity

Here, we report a novel amino-modified mesoporous-structured aluminum-based metal-organic framework adsorbent, MIL-68(Al)/MCM-41-NH₂, for dye sewage treatment. The introduction of molecular sieves overcomes the inherent defects of microporous MOFs in contaminant transfer and provides more active sites to enhance adsorption efficiency. Compared with using organic amino ligands directly, this strategy is ten times cheaper. The composite was well characterized and analyzed in terms of morphology, structure and chemical composition. Batch experiments were carried out to study the influences of essential factors on the process, such as pH and temperature. In addition, their interactions and the optimum conditions were examined using response surface methodology (RSM). The adsorption kinetics, isotherms and thermodynamics were systematically elucidated. In detail, the adsorption process conforms to pseudo-second-order kinetics and follows the Sips and Freundlich isothermal models. Moreover, the maximum adsorption capacity Q_s of methyl orange (MO) was 477 mg g^-1. It could be concluded that the process was spontaneous, exothermic, and entropy-reducing. Several binary dye systems have been designed for selective adsorption research. Our material has an affinity for anionic pigments. The adsorption mechanisms were discussed in depth. The electrostatic interaction might be the dominant effect. Meanwhile, hydrogen bonding, π-π stacking, and pore filling might be important driving forces. The excellent thermal stability and recyclability of the adsorbent are readily noticed. After five reuse cycles, the composite still possesses a removal efficiency of 90% for MO. Overall, the efficient and low-cost composite can be regarded as a promising adsorbent for the selective adsorption of anionic dyes from wastewater.

Iron porphyrin-TiO2 modulated peroxymonosulfate activation for efficient degradation of 2,4,6-trichlorophenol with high-valent iron-oxo species

Developing efficient catalysts with low cost and environmental friendliness for peroxymonosulfate (PMS) activation attracts broad interest. In this study, TiO₂-hemin was prepared by immobilizing hemin on TiO₂ using a ball milling method, demonstrating 126.9-fold enhanced catalytic degradation efficiency compared with unsupported hemin in the PMS activation system, with 92.9% of 2,4,6-trichlorophenol (2,4,6-TCP) removed in 10 min. The superior performance is attributed to the strong interaction between TiO₂ and hemin, which induces the redistribution of the electron density of hemin molecules. In the TiO₂-hemin/PMS system, sulfate radicals (SO₄^•-), hydroxyl radicals (•OH), singlet oxygen (¹O₂), and superoxide radicals (O₂^•-) were identified, which only played a minor role in the elimination of 2,4,6-TCP. Instead, high-valent iron-oxo species were proposed and identified as the primary active species. This study provides a facile strategy to enhance the activity of the biomimetic catalyst and offers insight into the catalytic mechanism of iron porphyrin with PMS activation.

State-of-the-Art on the Sulfate Radical-Advanced Oxidation Coupled with Nanomaterials: Biological and Environmental Applications

Sulfate radicals (SO₄^-·) play important biological roles in biomedical and environmental engineering, such as antimicrobial, antitumor, and disinfection. Compared with other common free radicals, it has the advantages of a longer half-life and higher oxidation potential, which could bring unexpected effects. These properties have prompted researchers to make great contributions to biology and environmental engineering by exploiting their properties. Peroxymonosulfate (PMS) and peroxydisulfate (PDS) are the main raw materials for SO₄^-· formation. Due to the remarkable progress in nanotechnology, a large number of nanomaterials have been explored that can efficiently activate PMS/PDS, which have been used to generate SO₄^-· for biological applications. Based on the superior properties and application potential of SO₄^-·, it is of great significance to review its chemical mechanism, biological effect, and application field. Therefore, in this review, we summarize the latest design of nanomaterials that can effectually activate PMS/PDS to create SO₄^-·, including metal-based nanomaterials, metal-free nanomaterials, and nanocomposites. Furthermore, we discuss the underlying mechanism of the activation of PMS/PDS using these nanomaterials and the application of SO₄^-· in the fields of environmental remediation and biomedicine, liberating the application potential of SO₄^-·. Finally, this review provides the existing problems and prospects of nanomaterials being used to generate SO₄^-· in the future, providing new ideas and possibilities for the development of biomedicine and environmental remediation.

Removal of Gaseous Volatile Organic Compounds by a Multiwalled Carbon Nanotubes/Peroxymonosulfate Wet Scrubber

In this study, a wet scrubber coupled with a persulfate-based advanced oxidation process [carbocatalysts/peroxymonosulfate (PMS)] was demonstrated to efficiently remove gaseous volatile organic compounds (VOCs). The removal efficiency of a representative VOC, styrene, was stable at above 98%, and an average mineralization rate was achieved at 76% during 2 h. The removal efficiency of the carbocatalysts/PMS wet scrubber for styrene was much higher than that of pure water, carbocatalysts/water, or PMS/water systems. Quenching experiments, electron spin resonance spectroscopy, in-situ Raman spectroscopy and density functional theory (DFT) calculations indicated that singlet oxygen (¹O₂) and oxidative complexes are the main reactive oxygen species and that both contributed to styrene removal. In particular, carbonyl groups (C═O) in the carbocatalyst were found to be the active sites for activating PMS during styrene oxidation. The role of ¹O₂ was discovered to be benzene ring breaking and a possible non-radical oxidation pathway of styrene was proposed based on time-of-flight mass spectroscopy which was further verified by DFT calculations. In particular, the electron transfer process of multi world carbon nanotubes-PMS* in styrene oxidation was further studied in-depth by experiments and DFT calculations. The unstable vinyl on styrene was simultaneously degraded by the oxidative complexes and ¹O₂ into benzene, and finally oxidized by ¹O₂ into H₂O and CO₂. This study provides an effective method for VOC removal and clearly illustrates the complete degradation mechanism of styrene in a nonradical PMS-based process by a wet scrubber.

Activation of persulfate via Mn doped Mg/Al layered double hydroxide for effective degradation of organics: Insights from chemical and structural variability of catalyst

Considerable interest has been focusing on the activation of peroxydisulfate (PDS) by layered double hydroxide (LDH) for degradation of organic pollutants. However, understanding the structure and chemistry of LDH by which the activation of PDS could achieve a high degradation efficiency of organic compounds is an unsolved and fundamental question in advanced oxidation processes (AOPs), and one which, if harnessed, could enable the rational design of LDH with desired material properties. In this work, Mg/Al-LDH was synthesized with variable structures and compositions through doping different proportions of Mn²⁺. We advanced to understand this question of how LDH by these characteristics can affect the activation of PDS for degradation of organic pollutants. At a relatively low dosage of Mn (˂ 1%) in Mg/Al-LDH, the degradation rate of phenol by LDH activated PDS increased with the increase content of Mn, which was achieved by an increase of catalytic sites in Mg/Al-LDH interlayer. Rather, higher content of Mn (˃ 1%) significantly lowered the degradation performance of phenol as the decrease of interlayer space resulted in reduction of PDS intercalation in LDH and the formation of secondary Mn-related minerals (i.e., Mn₃O₄) led to meaningless consumption of PDS. Finally, the degradation of phenol by LDH activated PDS followed a non-radical (¹O₂) mechanism. Our ability to quantify how the chemical and structural variability of LDH influence the activation of PDS for organic degradation could mark an important step toward synthesis strategies for advanced catalysts.

Enhanced photo-Fenton degradation of tetracycline hydrochloride by 2, 5-dioxido-1, 4-benzenedicarboxylate-functionalized MIL-100(Fe)

Heterogeneous photo-Fenton technology has drawn tremendous attention for removal of recalcitrant pollutants. Fe-based metal-organic frameworks (Fe-MOFs) are regarded to be superior candidates in wastewater treatment technology. However, the central metal sites of the MOFs are coordinated with the linkers, which reduces active site exposure and decelerates H₂O₂ activation. In this study, a series of 2, 5-dioxido-1, 4-benzenedicarboxylate (H₂DOBDC)-functionalized MIL-100(Fe) with enhanced degradation performance was successfully constructed via solvothermal strategy. The modified MIL-100(Fe) displayed an improvement in photo-Fenton behaviors. The photocatalytic rate constant of optimized MIL-100(Fe)-1/2/3 are 2.3, 3.6 and 4.4 times higher compared with the original MIL-100(Fe). The introduced H₂DOBDC accelerates the separation and transfer in photo-induced charges and promotes Fe(II)/Fe(III) cycle, thus improving the performance. •OH and •O₂^- are main reactive radicals in tetracycline (TCH) degradation. Dealkylation, hydroxylation, dehydration and dealdehyding are the main pathways for TCH degradation.

Remediation of sulfathiazole contaminated soil by peroxymonosulfate: Performance, mechanism and phytotoxicity

Peroxymonosulfate (PMS) was successfully adopted to remove organic pollutants in water, but it was rarely applied to soil remediation. Sulfathiazole (STZ) is a widely used sulfonamide antibiotic, while its residues have negative impacts on soil. To the best of our knowledge, this is the first attempt to apply PMS for the treatment of STZ-contaminated soil. The results showed that 4 mM PMS can degrade 96.54% of STZ in the soil within 60 min. Quenching and probe experiments revealed that singlet oxygen rather than hydroxyl radical and sulfate radical was the predominant reactive oxygen species responsible for STZ removal. The presence of Cl^-, SO₄^2-, NO₃^-, Fe³⁺, and HA enhanced the degradation efficiency of STZ, while HCO₃^- and Mn²⁺ presented an obstructive effect on STZ elimination at high concentrations. Different chemical extraction procedures were used to determine the bioavailability of the heavy metals. PMS oxidation process caused an unnoticeable influence of the concentrations of heavy metals except for the increase of Mn concentration and the decrease of Ba concentration. Moreover, the germination rate and stem length of wheat and radish both increased, indicating PMS oxidation reduced the toxicity of STZ, and the increase of Mn concentration did not cause a negative impact on their growth. Besides, the results of XRD and FTIR tests showed oxidation processes have negligible impacts on soil structure and composition. Based on intermediates identified, STZ degradation pathways in the PMS system were proposed. According to the results of this study, using PMS alone to repair STZ-contaminated soil is a relatively feasible, safe, and environmentally friendly technology.

Understanding the Iron-Cobalt Synergies in ZSM-5: Enhanced Peroxymonosulfate Activation and Organic Pollutant Degradation

Iron- and cobalt-based heterogeneous catalysts are widely applied for activating peroxymonosulfate (PMS) to degrade organic pollutants. However, few studies have unveiled the clear synergistic mechanism of iron and cobalt in ZSM-5. In this paper, the synergistic mechanism of enhanced PMS activation was revealed by constructing iron and cobalt bimetal modified ZSM-5 zeolite catalysts (FeCo-ZSM-5). The tetracycline hydrochloride (TCH) degradation experiments showed that the catalytic activity of FeCo-ZSM-5-2:3 was much higher than those of Fe-ZSM-5 and Co-ZSM-5. In addition, the influences of catalyst dosage, PMS concentration, reaction temperature, initial pH, and coexisting ions on TCH removal were systematically investigated in this paper. Density functional theory calculations indicated that Co was the main active site for PMS adsorption, and Fe increased the area of Co's positive potential mapped to the electron cloud. The Fe-Co bimetallic doping increased the area of positive potential mapped to the electron cloud and benefited the adsorption of PMS on the catalyst surface, which revealed the synergistic mechanism of bimetals. Electron paramagnetic resonance spectra and quenching experiments showed that sulfate radicals, singlet oxygen, and hydroxyl radicals were involved in the degradation of TCH. Furthermore, liquid chromatography-mass spectrometry was conducted to propose possible degradation pathways. This work provides certain guiding significance in understanding the synergistic effect of heterogeneous catalysts for tetracycline wastewater treatment.

Porous Aluminum-Based Metal-Organic Framework-Aminoclay Nanocomposite: Sustainable Synthesis and Ultrahigh Sorption of Cephalosporin Antibiotics

A novel sorbent was synthesized based on MIL-53(Al) MOF grown over an aminoclay (AC) platform, called MIL-53(Al)@AC nanocomposite, via a green and facile hydrothermal method. The nanocomposite was characterized using FT-IR, PXRD, BET, TEM, FESEM, EDS, XPS, TGA, DLS, and zeta potential analyses. BET analysis represented the porous nature and great surface area of MIL-53(Al)@AC. The high crystalline structure for the synthesized nanocomposite was verified using the PXRD pattern. FESEM, EDS, TEM, and XPS analysis proved the successful decoration of MIL-53(Al) over the AC platform. Cephalosporin antibiotics cefixime (CFX) and cephalexin (CPX), which are often present in wastewaters, were utilized to examine the sorption capacity of the nanocomposite. The significant influential factors such as pH, temperature, sorbent amount, ionic strength, and impurity were discussed. At an initial pH of 7.0 ± 0.1, the highest sorption capacities of CFX and CPX on MIL-53(Al)@AC were 784.14 and 747.91 mg g^-1 (T = 298 K, and sorbent amount = 0.1 g L^-1), which were 1.43 and 1.47 times greater compared to that of MIL-53(Al), respectively. The evaluation of experimental results was implemented through the Langmuir and Freundlich isotherm equations. The isothermal data were described nobly by the Freundlich isotherm, which confirmed multilayer adsorption on heterogeneous surfaces (R² > 0.970). A kinetic study indicated that the nanocomposite could adsorb the majority of cephalosporin antibiotics within 30 min. In addition, the experimental data were evaluated via pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. The results indicated that the pseudo-second-order equation agreed more closely with the kinetic data (R² > 0.990). Furthermore, the processes of adsorption were exothermic and spontaneous. The electrostatic attraction, hydrophobic interaction, π-π electron donor-acceptor effect, H-bond, and π-π stacking constituted the main sorption mechanisms. Finally, MIL-53(Al)@AC presented an excellent regeneration performance. Thus, the results revealed the potential application of the MIL-53(Al)@AC nanocomposite for water remediation.

Tuning parameters for the synthesis of MIL-53(Al): Mn doped MIL-53(Al) as a high potential catalyst for methanol dehydration

Recently, many studies are dealing with developments of Metal-Organic Frameworks (MOFs), especially MIL-53(Al), which shows high thermal and mechanical stability. Among these, optimizing the synthesis condition of MIL-53(Al) to obtain appropriate characteristics has attracted much attention in academia and the industry. Here, the effect of synthesis time and ligand to metal molar ratio on the hydrothermal synthesis of MIL-53(Al) are pursued. The synthesized MIL-53(Al) samples are characterized by X-ray diffraction (XRD), the Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy dispersive X-ray analysis (EDX), thermal gravimetric analysis (TGA), and nitrogen adsorption-desorption technique (BET). The present study shows that MIL-53(Al) can be conventionally synthesized with a high yield within a shorter reaction time than the previous studies. Furthermore, the catalytic activity of the optimized MIL-53(Al) in the pure and Mn-doped form is studied in a methanol dehydration reaction. It is thus inferred that this popular MOF in the Mn/MIL-53(Al) form has a high activity and DME selectivity during methanol conversion. Our present results confirm the merits of employing the MIL-53(Al) as a catalyst in methanol to DME conversion, which can be an avenue for the practical application of acidic catalyst.

Oxidative degradation of tetracycline using peroxymonosulfate activated by cobalt-doped pomelo peel carbon composite

Tetracycline (TC) is a typical ecotoxic antibiotic, which easily causes bacterial resistance. Therefore, it is necessary to remove TC from the water environment. In recent years, advanced oxidation processes (AOPs) rely on the use of highly reactive oxidizing sulfate radical which is turning into an increasingly popular as a tool of the removal of TC. In this study, cobalt-doped pomelo peel carbon composite (Co-PPCC) was prepared by the impregnation coprecipitation method to activate peroxymonosulfate (PMS) to remove TC. SEM, BET, XRD, FTIR, XPS, TGA, and other analytical techniques indicated that a carbon composite catalyst with excellent performance has been successfully prepared. TC was removed by the synergistic effect of adsorption and catalytic degradation processes. The adsorption capacity was limited (only approximately 20% within 60 min) and tending to saturation, which indicated that the removal of TC in the Co-PPCC/PMS system was mainly due to oxidative degradation. The influence of the Co-PPCC and PMS dosage, initial TC concentration, initial pH values, and coexisting anions on the removal efficiency of TC was investigated. When the Co-PPCC catalyst dosage was 1 g/L, PMS concentration was 2 g/L, and pH value was 11, the removal efficiency of TC with a concentration of 50 mg/L reached 99% within 60 min. Free radical quenching experiment and electron paramagnetic resonance (EPR) analysis indicated that the free radical and non-radical degradation processes exist in the Co-PPCC/PMS/TC system. The main degradation products and the possible transformation pathways of TC were explored by LC-MS. In addition, after four cycles of Co-PPCC tests, the removal efficiency of TC can reach 64%. This study provides a new method to reuse abandoned pomelo peels and synthesize an economical and environmentally friendly catalyst for activating peroxymonosulfate to remove TC antibiotics in water.

Facile synthesis of recyclable 3D gelatin aerogel decorated with MIL-88B(Fe) for activation peroxydisulfate degradation of norfloxacin

The application of traditional powder catalysts is limited by particle agglomeration and difficult recovery. In this work, a three-dimensional porous aerogel catalyst for organic pollutants degradation in water by activating peroxydisulfate (PDS) was successfully synthesized, which was obtained via directly mixing of MIL-88B(Fe) with sol precursors followed by vacuum freeze-drying and low-temperature calcination. MIL-88B(Fe)/gelatin aerogel-150/PDS (MGA-150/PDS) system displayed satisfactory norfloxacin (NOR) degradation performance, which could remove 98.7% of NOR in 90 min. Its reaction rate constant was 23.2 times higher than the gelatin aerogel/PDS (GA/PDS) system. In addition, Electron paramagnetic resonance (EPR) results and radical trapping experiments revealed both radicals (SO₄^•-, •OH) and non-radical (¹O₂) pathways had participated in NOR degradation, of which •OH was dominant. Possible degradation pathways were proposed. Moreover, the high degradation efficiency of NOR by MGA-150 composites could still be reached more than 90.0% even after 10 cycles, and the morphology and chemical structure of MGA-150 composites exhibited no significant changes, indicating the arrestive stability of aerogel composites. This progress not only proposed an effective catalyst for PDS activation, but also expanded views for the design and development of 3D functional materials.

Bicarbonate-enhanced iron-based Prussian blue analogs catalyze the Fenton-like degradation of p-nitrophenol

P-nitrophenol (PNP), a widely used compound, is harmful to the environment and human health. In this study, four iron-based Prussian blue analogs (PBAs) were prepared by coprecipitation (Co-Fe PBA, Mn-Fe PBA, Cu-Fe PBA and Fe-Fe PBA). The Co-Fe PBA exhibited high peroxymonosulfate (PMS) activation performance for PNP degradation, removing over 90% of PNP in 60 min at an optimal pH of 7, temperature at 30 ℃, initial concentration of 20 mg/L, PBA dose of 0.2 g/L and PMS dose of 1 g/L. The physicochemical properties of the Co-Fe PBA were investigated by various characterization methods. The catalytic activity of PBA and the influence of various process parameters and water quality on the catalytic reaction were investigated to elucidate the mechanism of p-nitrophenol degradation by PBA-activated persulfate. Moreover, the mechanism of accelerated degradation of PNP under HCO₃^- conditions and the role of major reactive oxides were determined by EPR measurement methods and free radical trapping experiments. HCO₃^- was found to directly activate PMS to produce reactive oxygen species, and ¹O₂, ∙OH and SO₄^∙- were all greatly increased. This work presents a promising green heterogeneous catalyst for the degradation of emerging contaminants (ECs) in real wastewater with natural organic matter and coexisting anions by PMS activation.