Heterogeneous Activation Of Peroxymonosulfate Research Articles

Unraveling the degradation of levofloxacin using highly efficient β-cyclodextrin-modified copper ferrite through peroxymonosulfate activation: Mechanistic performance and degradation pathways

In this study, a highly magnetic β-cyclodextrin-modified copper ferrite (CuFe2O4@β-CD) catalyst was developed utilizing a hydrothermal method, which was subsequently utilized to degrade Levofloxacin (LEV) antibiotic in aqueous solution via heterogeneous activation of peroxymonosulfate (PMS). The findings demonstrated that the 98.87 % degradation of LEV was achieved with CuFe2O4@β-CD/PMS, much higher than that of pure CuFe2O4/PMS (87.78 %) within a 24-minute time frame under optimal parameters ([CuFe2O4@β-CD] = 0.4 g/L, [PMS] = 0.4 mM, [LEV] = 25 mg/L, pH = 6), and CuFe2O4@β-CD/PMS was present. The rate constant of CuFe2O4@β-CD/PMS (0.1608 min−1) was much greater than that of the CuFe2O4/PMS system (0.0822 min−1). The increased availability of active sites for PMS activation may be credited to the larger surface area (189.42 m2/g) of the CuFe2O4@β-CD catalyst in comparison to the pristine CuFe2O4 (87.76 m2/g), which facilitated the improved degradation of LEV. Additionally, the impact of various reaction parameters and intervening anions on the degradation of LEV was investigated. The emergence of free radicals (SO4•−, •OH, and 1O2) was corroborated via electron paramagnetic resonance and scavenging experiments. On the basis of recognizing reaction intermediates, a hypothetical degradation mechanism for LEV was developed. PMS activation was caused by the transformation of Cu+/Cu2+ and Fe3+/Fe2+ pairs, which was accomplished via radical and non-radical pathways. Also, CuFe2O4@β-CD demonstrated exceptional stability and retained its catalytic activity after five concurrent cycles. In conclusion, the CuFe2O4@β-CD catalyst demonstrated encouraging potential in the context of purifying LEV-contaminated water.

Molybdenum nitride(γ-Mo2N) as a novel co-catalyst to enhance Fe(III)/Fe(II) cycle for homogeneous and heterogeneous peroxymonosulfate activation: Performance and mechanism

In this work, molybdenum nitride (γ-Mo2N) was investigated for the first time as a co-catalyst to accelerate the activation of PMS by enhancing iron cycling for the treatment of acid orange 7. γ-Mo2N/PMS/Fe3+ system showed excellent performance: 95% of acid orange 7 were highly degraded within 9 mins, and the γ-Mo2N proved to be stable and reusable after a 4-cycles experiment. The homogeneous Fe2+-activated PMS process was determined by testing the change in the concentration of iron species during the experiments. In addition, the heterogeneous activation of PMS by the iron retained on the catalyst surface was further determined by ICP-OES and the degradation effect of the *γ-Mo2N (used γ-Mo2N)/PMS system. In addition, the main active species for the homogeneous and heterogeneous activation of the PMS process were identified as hydroxyl radicals(⋅OH), sulfate radicals (SO4·-) and singlet oxygen (1O2) by EPR tests. Based on XPS, TEM and FT-IR analyses, a possible mechanism was proposed: Mo(III) and Mo(IV) play the role in the reduction of Fe3+, and γ-Mo2N forms Mo-N-O-Fe as well as Mo-N-Fe electron-transfer processes with iron in the reaction, which correspond to heterogeneous and homogeneous activation for PMS to achieve efficient degradation of the target. In summary, this work clarifies that γ-Mo2N can act as an efficient co-catalyst in the γ-Mo2N/PMS/Fe3+ system to accelerate the Fe(III)/Fe(II) cycle and thus promote homogeneous and heterogeneous PMS activation, which provides a promising γ-Mo2N co-catalyzed AOPs for rapid and efficient abatement of organic contaminants.

Degradation of atrazine by N-doped graphitic carbon encapsulated Nickel-iron alloy via heterogeneous activation of peroxymonosulfate

Heterogeneous magnetic catalysts for peroxymonosulfate (PMS) activation that are used to degrade pollutants have attracted growing attention, and bimetallic alloy catalysts have excellent catalytic performance. In this study, nitrogen-doped graphite carbon encapsulated NiFe (NiFe@NC) alloy catalysts were synthesized using nickel-iron Prussian blue analog precursors to remove atrazine (ATZ) via the activation of PMS. The effects of various operating parameters (NiFe@NC dosage, PMS concentration, initial solution pH, and reaction temperature), and the effects of co-existing components were investigated. The synergistic catalysis of Ni and Fe gives NiFe@NC good catalytic properties. The NiFe@NC/PMS system achieved 100% removal of 10 mg L−1 ATZ was achieved in 30 min with an initial pH of 5.9; the TOF was 4.33 min−1, and the system exhibited resistance to interference from many co-existing substances. The graphite-carbon core-shell structure of NiFe@NC slowed down the leaching rate of metal ions and had good stability. Redox cycles in the system were achieved by facilitating the interaction between the transition metal and HSO5-, ensuring the continuous generation of reactive oxygen species. Ecotoxicity assessment showed that the toxicity level was significantly reduced after treatment. The total treatment cost of treating 1 m3 wastewater was lower than that of Fenton sludge catalyst. A continuous flow reactor was constructed to achieve continuous degradation of ATZ for long periods. This study expanded the application of PMS advanced oxidation technology by synthesizing an economical and recyclable magnetic catalyst and provided new insights for the removal of refractory organic matter.

Degradation of neonicotinoids with different molecular structures in heterogeneous peroxymonosulfate activation system through different oxidation pathways

Degradation of neonicotinoids with different molecular structures in heterogeneous peroxymonosulfate activation system through different oxidation pathways

Efficient heterogeneous activation of peroxymonosulfate by manganese-doped LaCoO3 perovskites for metronidazole degradation: A mechanistic study and reaction pathways

Herein, manganese-doped perovskites LaCo1−xMnxO3 (x = 0, 0.05, 0.1, and 0.2) were synthesized by the so-gel process to dominantly activate PMS for Metronidazole (2-methyl-5-nitroimidazole-1-ethanol (MNZ) degradation. The results revealed that the MNZ degradation rate under the LaCo0.8Mno.2O3/PMS system reached 99.42 % in 30 min with a rate constant of 0.1616 min−1, which is significantly higher than the LaCoO3/PMS system under optimal reaction conditions (LaCo0.8Mn0.2O3 = 0.4 g/L, [PMS] = 0.4 mM, [MNZ] = 15 mg/L, pH = 7, T = 25 ± 2 °C). LaCo0.8Mn0.2O3 has demonstrated a higher surface area (44.35 m2g−1) as compared to pristine LaCoO3 (7.89 m2g−1), suggesting that Mn doping remarkably improves the catalytic activity and provides more active sites to the LaCo0.8Mn0.2O3/PMS to increase MNZ degradation efficiency. Meanwhile, the impact of various influencing factors and associated anions on MNZ degradation was examined. On the surface of LaCo0.8Mn0.2O3, photogenerated electrons and the conversion of Co2+/Mn3+ to Co3+/Mn4+ both played a part in PMS activation for MNZ degradation. The changes in valence states of elements were further corroborated through XPS analysis, which confirmed the potential application of the LaCo0.8Mn0.2O3 catalyst in MNZ degradation process. The generation of SO4•−,HO•, and 1O2 was confirmed through radical quenching studies and further validated by EPR measurements. It is evident from results that SO4•−, contributed significantly towards the degradation of MNZ along with minor role of HO•, and 1O2. This study presents insight into the improvement of new perovskite catalysts for the elimination of organic pollutants in water.

Manganese oxide on activated carbon with peroxymonosulfate activation for enhanced ciprofloxacin degradation: Activation mechanism and degradation pathway

Ciprofloxacin, a threat to the ecosystem, can be effectively eliminated through heterogeneous activation of peroxymonosulfate (PMS) by metallic oxide catalyst-based advanced oxidation processes (AOPs). Manganese oxide (MnOx) is one of the most promising metallic oxide catalysts and deserves in-depth research. Herein, a MnOx catalyst loaded on activated carbon (MnOx/AC) was synthesized for the PMS activation in ciprofloxacin degradation. Due to the anchoring effect of AC on MnOx, the MnOx/AC catalyst demonstrated excellent performance and good reusability in ciprofloxacin degradation. Characterizations indicated that redox circles among valence states of Mn(II, III, and IV) species on the catalyst surface triggers the generation of reactive oxygen species (ROS), including 1O2, HO and SO4−. Notably, predominant species was 1O2 (63.75%), which ascribed to the increment of Mn(II) and the consumption of lattice oxygen. Moreover, the PMS adsorption on the MnOx/AC catalyst was a crucial step in ciprofloxacin degradation, and the acidic condition was favored. Furthermore, seven intermediates were detected by liquid chromatograph mass spectrometer during the ciprofloxacin degradation, thus establishing the degradation pathway of the ciprofloxacin. This study provided insights into activation mechanism and degradation pathway for the ciprofloxacin degradation by MnOx in water treatment using PMS–AOPs reaction system.

A Novel Fe3O4@C/RM Composite Fabricated from Red Mud and Scrap Tire-Derived Carbon Black: Heterogeneous Activation of Peroxymonosulfate for Oxidative Degradation of Orange II

A Novel Fe3O4@C/RM Composite Fabricated from Red Mud and Scrap Tire-Derived Carbon Black: Heterogeneous Activation of Peroxymonosulfate for Oxidative Degradation of Orange II

Efficient degradation of oxytetracycline by glucose modified CuFeO2 in visible-light-assisted heterogeneous activation of peroxymonosulfate system：Performance, mechanism and DFT calculation

Visible-light-assisted heterogeneous activation of peroxymonosulfate (PMS) exhibits great potential in refractory wastewater treatment. Efficient and environmental-friendly heterogeneous catalysts are the key to drive sustainable development of the process. Herein, the glucose modified CuFeO2 (Glu/CFO) catalysts were synthesized to activate PMS and degrade oxytetracycline (OTC). The modification of glucose introduced more active functional groups on the Glu/CFO surface, the narrowed band gap and increased photogenerated electrons transfer of CuFeO2. The Glu/CFO with 0.5 g glucose possessed more superior catalytic performance than other as-prepared samples. Furthermore, the Glu/CFO-0.5 showed superior reuse performance and high material stability under long-term operation. Significantly, the photogenerated electrons effectively promoted the in-situ cycle of Fe3+ and Cu2+ to Fe2+ and Cu+ on the surface of Glu/CFO-0.5, accelerating the generation of reactive oxygen species (ROSs) and OTC degradation. The results of free radical quenching experiment and ESR demonstrated that the non-free radical pathway dominated by 1O2 was the main way of OTC degradation. Combining XPS spectra, the degradation mechanism of OTC in Vis/PMS/Glu/CFO-0.5 system was elucidated. Based on HPLC-MS analysis and DFT calculation, the possible degradation pathways of OTC were explored in depth, and the toxicity of the corresponding products was analyzed based on quantitative structure–activity relationship predictions.

Textile Waste-Derived Cobalt Nanoparticles Embedded in Active Carbon Fiber for Efficient Activation of Peroxymonosulfate to Remove Organic Pollutants.

Burning and dumping textile wastes have caused serious damage to the environment and are a huge waste of resources. In this work, cobalt nanoparticles embedded in active carbon fiber (Co/ACF) were prepared from bio-based fabric wastes, including cotton, flax and viscose. The obtained Co/ACF was applied as a catalyst for the heterogeneous activation of peroxymonosulfate (PMS) to remove bisphenol A (BPA) from an aqueous solution. The results showed that cotton-, flax- and viscose-derived Co/ACF all exhibited excellent performance for BPA degradation; over ~97.0% of BPA was removed within 8 min. The Co/ACF/PMS system exhibited a wide operating pH range, with a low consumption of the catalyst (0.1 g L-1) and PMS (0.14 g L-1). The high specific surface area (342 m2/g) and mesoporous structure of Co/ACF allowed the efficient adsorption of pollutants as well as provided more accessible active sites for PMS activation. This study provided an example of using textile wastes to produce a valuable and recyclable catalyst for environmental remediation.

Enhanced degradation of chloramphenicol via heterogeneous activation of peroxymonosulfate by Fe3O4 and gallic acid

In this study, we demonstrated the effective degradation of wide-spectrum antibiotic chloramphenicol (CAP) by Fe3O4/peroxymonosulfate (PMS) system modified by gallic acid (GA). GA/Fe3O4/PMS showed a substantially higher degradation rate (77.6%) than Fe3O4/PMS (8.3%). The active components were detected by electron spin-resonance spectroscopy (ESR) and the quenching experiments. The results showed that the hydroxyl radical (HO•) was the main reason for the degradation of CAP. In the GA/Fe3O4/PMS system, the trace amount of dissolved iron ion were not the main species that activated PMS. Surface characterization and theoretical simulations showed that Fe atoms on Fe3O4 were responsible for PMS activation rather than a homogenous reaction. Five probable CAP degradation pathways were identified by density functional theory (DFT) calculations and liquid-phase mass spectrometry. Finally, the reusability of Fe3O4 was measured, and the GA/Fe3O4/PMS system maintained high efficiency after 5 times applications. The total organic carbon (TOC) removal rate reached 46.5% after reacting for 12 h. The gallic acid effectively promotes the circulation of Fe(II)/Fe(III) on solid surfaces and enhanced the degradation capacity of the original system. The research proposed a new way of directly employing plant polyphenols to boost the degradation ability of contaminants in heterogeneous systems.

Heterogeneous activation of peroxymonosulfate by recyclable magnetic CuO/Fe3O4 nanosheets for efficient degradation of organic pollutants

In this work, recyclable magnetic CuO/Fe3O4 nanosheetswere successfully synthesized via a simple continuous precipitation method, which can effectively activate peroxymonosulfate (PMS) to decompose organic pollutants. The properties of CuO/Fe3O4 nanosheets were measured by a series of characterization techniques. CuO/Fe3O4 composites showed highly effectiveness for PMS activation to degrade methyl blue (MB), and several influencing factors were investigated, such as initial pH, catalyst dosage, PMS concentration and reaction temperature. Although CuO/Fe3O4/PMS system exhibited effectiveness for MB degradation in a wide pH range, the natural pH value was the best. The increase in reaction temperature is favorable for MB degradation, and the activation energy was calculated as 40.34 kJ/mol. Quenching experiments and electron spin resonance (ESR) analysis proved that OH, SO4- and 1O2 were generated in the CuO/Fe3O4/PMS system, and SO4- and 1O2 played the dominant role. Moreover, CuO/Fe3O4 remained good activity and stability after being recycled five times. In addition, the complete degradation of methylene orange (MO) and tetracycline hydrochloride (TC), and MB degradation in tap water and lake water further confirmed the wide applicability of the CuO/Fe3O4/PMS system. These results exhibited that CuO/Fe3O4/PMS system has great advantages of high removal efficiency, reusability and wide applicability, demonstrating its potential environmental application in the treatment of organic wastewater.

Efficient heterogeneous activation of peroxymonosulfate by Ag-doped CoFe2O4 nanoparticles for sulfamethoxazole degradation

In this work, silver-doped cobalt ferrite catalysts Agx-CoFe2O4 (x = n(Ag+): n(Fe3+); x = 0, 0.02, 0.04, 0.06, and 0.08) were synthesized through the reverse co-precipitation method and employed to activate peroxymonosulfate (PMS) for sulfamethoxazole (SMX) degradation. Ag0.06-CoFe2O4 exhibited the best catalytic activity and PMS utilization efficiency, indicating the optimal silver doping ratio. The characterization results revealed that Ag doping led to the exposure of more active sites and the increase of the concentration of oxygen vacancies (OV). The effects of Ag0.06-CoFe2O4 dosage, PMS concentration, initial pH, inorganic ions, and humic acid on SMX degradation by Ag0.06-CoFe2O4/PMS system were investigated. The utilization of 0.1 g/L Ag0.06-CoFe2O4 and 0.1 mM PMS resulted in a remarkable 95.1 % degradation efficiency of 10 μM SMX in 30 min at initial pH of 5.0. Quenching experiments and electron paramagnetic resonance (EPR) analysis revealed the presence of both radical species (HO•, SO4•− and O2•−) and non-radical species (1O2) in Ag0.06-CoFe2O4/PMS system, among which SO4•− and 1O2 played a predominant role in SMX degradation. The catalytic cycle between≡CoOH+/≡CoO+ and PMS and the interaction of OV with adsorbed oxygen should contribute to PMS activation. The cycling experiments and X-ray diffraction (XRD) patterns before and after the reaction showed that Ag0.06-CoFe2O4 exhibited remarkable stability and reusability. The transformation products (TPs) of SMX were identified, and three possible degradation pathways were proposed. Most of these TPs demonstrated lower toxicity compared to SMX, as predicted by the Ecological Structure−Activity Relationship Model.

Synergistic effect of iron and nitrogen on porous carbon to improve electron transfer efficiency resulting in the enhancement of tetracycline hydrochloride removal

Developing transition metal/nitrogen carbon catalysts for efficient pollutant removal presented an attractive option for water environment remediation. In this work, the iron (Fe), nitrogen (N) co-doped porous carbon nanoparticles (FeN/C) were prepared for heterogeneous activation of peroxymonosulfate and efficient oxidation of tetracycline hydrochloride (TC). Fe nanoparticles were encapsulated in the carbon to reduce the loss of Fe during the catalysis processes. As a catalyst, the sample of 20FeN/C exhibited an excellent catalytic activity of tetracycline hydrochloride with a removal rate of 91.2 % and a rate constant of 0.6653 min−1 in peroxymonosulfate (PMS) system. And the prepared catalysts presented the strong adaptability, which was worked efficient in a wide range pH and some anions solution. The high efficiency could attribute to the interaction of Fe and N, which effectively improved the electron transfer efficiency in this 20FeN/C activated PMS system. Combining with the results of electron paramagnetic resonance (EPR), in-situ Raman spectra, and X-ray photoelectron spectroscopy (XPS), electrons transfer was confirmed as a dominating non-radical process of TC degradation. It was confirmed that the doping of iron and nitrogen could collectively promote the electron transfer between material and PMS, and the activated PMS* reacted with TC via electron-rich nitrogen active sites of the material surface, then the TC degradation was enhanced. The received finding is of great significance to supplement the mechanism of electron transfer and provides a new idea on the synthesis of iron/nitrogen co-doped carbon catalysts to achieve high efficiency of TC removal.

Electrochemical enhanced heterogeneous activation of peroxymonosulfate by CoFe2O4 nanoparticles to degrade moxifloxacin

The catalytic mechanism of CoFe2O4 nanoparticles (NPs) was investigated in the system of electrochemical enhanced heterogeneous activation of peroxymonosulfate (EC/CoFe2O4/PMS) with moxifloxacin (MOX) as target contaminant. The removal efficiencies of MOX in PMS, CoFe2O4, EC, CoFe2O4/PMS, and EC/CoFe2O4/PMS system were 18.3%, 36.1%, 43.7%, 96.9%, and 98.3%, respectively. Although there was no synergy effect between EC and heterogeneous catalytic oxidation reaction (HCOR) on MOX removal, the value of apparent rate constant (karc) was much higher in EC/CoFe2O4/PMS system (0.24 min−1) compared with CoFe2O4/PMS system (0.13 min−1). Therefore, EC not only kept the structure of CoFe2O4 NPs stable, but also significantly accelerated the reaction rate of HCOR. Meanwhile, according to electrochemical impedance spectra of catalysts synthesized based on ion-substitution strategy and the EC-HCOR experimental results, the decisive role of Co in PMS activation and the electron transfer between Co and Fe were confirmed. The TOC removal efficiency was reached 74.4% as the ratio of PMS to CoFe2O4 NPs being 0.8 mM to 50 mg/L (30 min), and further improved to 87.6% with batch addition (0.25 mM per 30 min) of PMS (120 min, CoFe2O4 = 100 mg/L). The research results could improve the understanding of catalytic mechanism of spinel oxide in electrochemical system.

Cobalt nanoparticles supported on porous carbon nanofiber as efficient catalyst for heterogeneous activation of peroxymonosulfate towards the degradation of organic pollutants

In this work, cobalt-porous carbon nanofiber (Co-PCNF) was developed as a robust catalyst for the activation of peroxymonosulfate (PMS) to eliminate organic pollutants in water. Carbamazepine (CBZ) was severed as the probe to examine the ability of Co-PCNF for activating PMS. The microporous honeycomb-like structure endowed Co-PCNF with excellent catalytic activity to activate PMS as evidenced by the rapid removal rate of CBZ (0.1269 min–1) in the existence of 0.1 g/L Co-PCNF and 0.25 g/L PMS. The degradation rate of CBZ can be maintained at 89 % after five runs and the leaching concentration of Co2+ can be neglected, suggesting the extraordinary stability of Co-PCNF reuse. Meanwhile, this system was used to degrade other organic contaminates and achieved satisfactory results, confirming the good universality of Co-PCNF/PMS system. Furthermore, the effects of catalyst and PMS dosage, pH, and co-existing ions on CBZ removal were discussed. Finally, radical identification results prove that SO4·–,·OH, 1O2, and O2·– are generated during the process of PMS activation, and a possible activation mechanism is proposed based on the aforementioned findings. This study can not only provide a method for organic pollutants elimination, but also offer a reference for designing robust heterogeneous PMS catalysts.

3D N-doped carbon derived from zeolitic imidazole framework as heterogeneous catalysts for decomposition of pulp and paper mill effluent: Optimization and kinetics study

Three specific catalysts, namely ZIF-67 (zeolitic imidazolate framework-67), Co@NCF (Co@Nitrogen-Doped Carbon Framework), and 3D NCF (Three-Dimensional Nitrogen-Doped Carbon Framework), were prepared and studied for pulp and paper mill effluent degradation using heterogeneous activation of peroxymonosulfate (PMS). Numerous characterizations, including scanning electron microscopy (SEM), X-ray diffraction (XRD), and N2 adsorption, were used to characterize the properties of three different catalysts. 3D NCF is remarkably effective at heterogeneous activation of PMS to generate sulfate radicals to degrade pulp and paper mill effluent (PPME) compared to the other as-prepared catalysts. The catalytic activity reveals a sequence of 3D NCF > Co@NCF > ZIF-67.3D NCF could degrade organic pollutants in 30 min at an initial COD concentration of 1146 mg/L of PPME, 0.2 g/L catalysts, 2 g/L PMS, and 50 °C. Consequently, it was observed that the degradation of PPME using 3D NCF followed first-order kinetics, with an activation energy of 40.54 kJ mol−1. Overall, 3D NCF/PMS system reveals promising performance for PPME removal.

Heterogeneous activation of peroxymonosulfate by flower-like cobalt sulfide enhanced sulfamethoxazole degradation via non-radical pathways

The treatment of emerging pollutants has become a challenging and multidisciplinary subject. Advanced oxidation processes based on persulfate are a strategic opportunity to address this issue, with research into catalysts and catalytic processes being the focus of this process. In this work, flower-like cobalt sulfide (F-CoS) particles acted as catalysts in peroxymonosulfate (PMS) activation for degrading an organic pollutant, sulfamethoxazole (SMX). The results indicated that F-CoS/PMS combined system performed excellently, with SMX being completely oxidized within 10 min. And the system exhibited superior resistance to environmental factors (e.g. pH and anions). Radicals quenching and electron paramagnetic resonance (EPR) analyses indicated that non-radical pathways based on high-valent cobalt-oxo (Co(IV)) species and 1O2 take a dominant position in SMX degradation, instead of SO4•− and •OH. Electrochemical, in-situ Raman and density functional theory (DFT) calculations revealed that PMS interacts with Co sites on the F-CoS surface, and then electronic transfer processes occurred, in which PMS acts as an electron acceptor to produce Co(IV) species and as an electron donor to produce 1O2. This study not only implies a method with great potential application in organic wastewater treatment but also contributes to further comprehending the heterogeneous activation process and catalytic mechanism of PMS.

Activation of peroxymonosulfate by FeVO3-x for the degradation of carbamazepine: Vanadium mediated electron shuttle and oxygen vacancy modulated interface chemistry

Fast Fe(III)/Fe(II) circulation in heterogeneous peroxymonosulfate (PMS) activation remains as a bottleneck issue that restricts the development of PMS based advanced oxidation processes. Herein, we proposed a facile ammonia reduction strategy and synthesized a novel FeVO3-x catalysts to activate PMS for the degradation of a typical pharmaceutical, carbamazepine (CBZ). Rapid CBZ removal could be achieved within 10 min, which outperforms most of the other iron or vanadium-based catalysts. Electron paramagnetic resonance analysis and chemical probe experiments revealed SO4•−, •OH, O2•− and high valent iron (Fe(IV)) were all generated in this system, but SO4•− and Fe(IV) primarily contributed to the degradation of CBZ. Besides, X-ray photoelectron spectroscopy and X-ray adsorption spectroscopy indicated that both the generated low-valent V provides and oxygen vacancy acted as superior electron donors and accelerated internal electron transfer via the unsaturated V−O−Fe bond. Finally, the proposed system also exhibited satisfactory performance in practical applications. This work provides a promising platform in heterogeneous PMS activation.

Yeast-derived biochar to load CoFe2O4: Degradation of tetracycline hydrochloride by heterogeneous activation of peroxymonosulfate

The development of high-efficiency catalysts is essential for activating peroxymonosulfate (PMS) to degrade organic pollutants. In this study, yeast-derived biochar (YBC) supported cobalt ferrite composite catalyst (CoFe2O4/YBC) was successfully synthesized, which can heterogeneous activate PMS to degrade tetracycline hydrochloride (TCH). The results showed that CoFe2O4/YBC could activate PMS effectively and stably owing to the synergistic effect of YBC and CoFe2O4. The degradation rate of TCH was nearly 95% under the optimal conditions, and it was still more than 90% after four cycles. Furthermore, according to quenching tests and electron paramagnetic resonance (EPR) detection, it was confirmed that ·OH, SO4·-, O2·-, and 1O2 were involved in TCH degradation, and 1O2 played a key role. After identifying the intermediates produced by TCH's degradation, two potential TCH degradation pathways were suggested. Further ECOSAR (2.0) software analysis revealed that the ecotoxicity of the final degradation products of TCH was small. This study demonstrates that the as-prepared CoFe2O4/YBC is an efficient and environmentally friendly PMS activation catalyst with great potential for application in the remediation of polluted aquatic environments.

Enhanced Heterogeneous Peroxymonosulfate Activation by MOF-Derived Magnetic Carbonaceous Nanocomposite for Phenol Degradation.

Degradation efficiency and catalyst stability are crucial issues in the control of organic compounds in wastewater by advanced oxidation processes (AOPs). However, it is difficult for catalysts used in AOPs to have both high catalytic activity and high stability. Combined with the excellent activity of cobalt/copper oxides and the good stability of carbon, highly dispersed cobalt-oxide and copper-oxide nanoparticles embedded in carbon-matrix composites (Co-Cu@C) were prepared for the catalytic activation of peroxymonosulfate (PMS). The catalysts exhibited a stable structure and excellent performance for complete phenol degradation (20 mg L-1) within 5 min in the Cu-Co@C-5/PMS system, as well as low metal-ion-leaching rates and great reusability. Moreover, a quenching test and an EPR analysis revealed that ·OH, O2·-, and 1O2 were generated in the Co-Cu@C/PMS system for phenol degradation. The possible mechanism for the radical and non-radical pathways in the activation of the PMS by the Co-Cu@C was proposed. The present study provides a new strategy with which to construct heterostructures for environmentally friendly and efficient PMS-activation catalysts.