Superoxide radical mediated Mn(III) formation is the key process in the activation of peroxymonosulfate (PMS) by Mn-incorporated bacterial-derived biochar

Gao, Bixia; Zhu, Simeng; Gu, Jialiang; Liu, Yang; Yi, Xiaoyan; Zhou, Hao

doi:10.1016/j.jhazmat.2022.128549

Cited by 79 publications

(10 citation statements)

References 55 publications

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“…The intrinsic catalytic performance of MnN 5 was superior to that of many reported Mn-based catalysts and Cu/Fe SACs (Figure S15 and Table S5). ,,− More importantly, MnN 5 still retained high activity after six successive catalytic recycles (Figure S16), implying its long-term stability. MnN 5 was also more active than MnN 4 to remove various refractory pollutants via efficient PMS activation, including phenol, bisphenol A, sulfathiazole, and sulfamethoxazole (Figure S17).…”

Section: Resultsmentioning

confidence: 96%

Single-Atom MnN₅ Catalytic Sites Enable Efficient Peroxymonosulfate Activation by Forming Highly Reactive Mn(IV)–Oxo Species

Miao

Song

Lang

et al. 2023

Environ. Sci. Technol.

106

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Four-nitrogen-coordinated transitional metal (MN 4 ) configurations in single-atom catalysts (SACs) are broadly recognized as the most efficient active sites in peroxymonosulfate (PMS)-based advanced oxidation processes. However, SACs with a coordination number higher than four are rarely explored, which represents a fundamental missed opportunity for coordination chemistry to boost PMS activation and degradation of recalcitrant organic pollutants. We experimentally and theoretically demonstrate here that five-nitrogen-coordinated Mn (MnN 5 ) sites more effectively activate PMS than MnN 4 sites, by facilitating the cleavage of the O−O bond into highvalent Mn(IV)−oxo species with nearly 100% selectivity. The high activity of MnN 5 was discerned to be due to the formation of higher-spin-state N 5 Mn(IV)�O species, which enable efficient two-electron transfer from organics to Mn sites through a lower-energybarrier pathway. Overall, this work demonstrates the importance of high coordination numbers in SACs for efficient PMS activation and informs the design of next-generation environmental catalysts.

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Section: Resultsmentioning

confidence: 96%

Single-Atom MnN₅ Catalytic Sites Enable Efficient Peroxymonosulfate Activation by Forming Highly Reactive Mn(IV)–Oxo Species

Miao

Song

Lang

et al. 2023

Environ. Sci. Technol.

106

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“…As an electron donor, MC-LR ( E h = −0.21 V) and phenol ( E h = −0.63 V) have relatively low reaction voltage, and are easily oxidized by · O 2 – (−0.56 V). However, for deltamethrin ( E h = −1.6 V) and ATZ ( E h = +0.24 V), their electron-withdrawing group (C–N and N–Cl) increases resistance to the · O 2 – attack. , Furthermore, the surface negative charge on MnBC-H5 repels with the same negatively charged ATZ, resulting in less than 15% adsorption (Figure S22), which may also be one of the reasons for its poor degradation efficiency. Thus, the MnBC-H5 system can produce · O 2 – to selectively degrade some organic pollutants under visible light radiation.…”

Section: Resultsmentioning

confidence: 99%

“…Persulfates can be activated through two pathways: one involving nonfree radicals and the other generating reactive oxygen species (ROS). Both the pathways involve electron transfer. , Metal atoms integrated into carbon bases accelerate the transfer of electrons from biochar to persulfate, increasing the oxidation capability of organic pollutants, as does the “charge pile.” Molecular oxygen (O 2 ) has an O–O bond similar to that of persulfate and thus can be activated by these integrated catalyst sites.…”

Section: Introductionmentioning

confidence: 99%

Insights into O₂ Activation via Mn^IIIOOH Species on Mn-Rich Biochar

Fang,

Ying,

Niu

et al. 2023

ACS Catal.

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Although metal-rich biochar (M-BC) is widely used in soil remediation and pollution control, the activation mechanism of molecular oxygen (O2) by M-BC still needs to be clarified due to the low metal loading. In this study, we enhanced the manganese content of low-temperature manganese-rich biochar (Mn-BC) by treating it with hydrogen peroxide (H2O2), resulting in the formation of MnBC-Hx (where x represents the volume of H2O2 used in mL). MnBC-H5 was particularly effective in activating O2, leading to the successful degradation of phenol and dyes. Characterizations showed that the MnII in the outer layer of MnC2O4·2H2O nanoparticles evenly dispersed over Mn-BC was oxidized to MnIII by H2O2. This process was accompanied by the removal of coordinated H2O, resulting in the formation of MnIIIC2O4 on MnBC-H5. Under visible light irradiation, MnIII can bind to O2 to form MnIIIOOH species, which facilitates the transfer of charges and generates superoxide radicals (·O2 –) that effectively degrade organics. Notably, MnIII of MnBC-H5 remains stable after the organic degradation reaction. This study will not only provide a theoretical basis for developing environmentally friendly biochar-based catalysts but also promote the study of the environmental effects of biochar.

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“…•− serves as a precursor to other reactive species such as • OH. 46,47 The nonradical oxidation pathway involves reactive species such as singlet oxygen 1 O 2 , high-valent metals, and surface-activated PS (or surface-active PS complex). Note that there are two low-lying-state oxygen species, 1 Δ g O 2 and 1 Σ g + O 2 .…”

Section: Environmental Sciencementioning

confidence: 99%

“…Only limited research has confirmed the contribution of O 2 •– for the direct degradation of contaminants . This could be attributed to relatively low reactivity of O 2 •– with organic contaminants. , Other studies showed that O 2 •– serves as a precursor to other reactive species such as • OH. , The nonradical oxidation pathway involves reactive species such as singlet oxygen 1 O 2 , high-valent metals, and surface-activated PS (or surface-active PS complex). Note that there are two low-lying-state oxygen species, 1 Δ g O 2 and 1 Σ g + O 2 .…”

Section: Ps Activation Approachesmentioning

confidence: 99%

Merits and Limitations of Radical vs. Nonradical Pathways in Persulfate-Based Advanced Oxidation Processes

Yan

Wei

Duan

et al. 2023

Environ. Sci. Technol.

185

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Urbanization and industrialization have exerted significant adverse effects on water quality, resulting in a growing need for reliable and eco-friendly treatment technologies. Persulfate (PS)-based advanced oxidation processes (AOPs) are emerging as viable technologies to treat challenging industrial wastewaters or remediate groundwater impacted by hazardous wastes. While the generated reactive species can degrade a variety of priority organic contaminants through radical and nonradical pathways, there is a lack of systematic and in-depth comparison of these pathways for practical implementation in different treatment scenarios. Our comparative analysis of reaction rate constants for radical vs. nonradical species indicates that radical-based AOPs may achieve high removal efficiency of organic contaminants with relatively short contact time. Nonradical AOPs feature advantages with minimal water matrix interference for complex wastewater treatments. Nonradical species (e.g., singlet oxygen, high-valent metals, and surface activated PS) preferentially react with contaminants bearing electron-donating groups, allowing enhancement of degradation efficiency of known target contaminants. For byproduct formation, analytical limitations and computational chemistry applications are also considered. Finally, we propose a holistically estimated electrical energy per order of reaction (EE/O) parameter and show significantly higher energy requirements for the nonradical pathways. Overall, these critical comparisons help prioritize basic research on PS-based AOPs and inform the merits and limitations of system-specific applications.

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Superoxide radical mediated Mn(III) formation is the key process in the activation of peroxymonosulfate (PMS) by Mn-incorporated bacterial-derived biochar

Cited by 79 publications

References 55 publications

Single-Atom MnN₅ Catalytic Sites Enable Efficient Peroxymonosulfate Activation by Forming Highly Reactive Mn(IV)–Oxo Species

Single-Atom MnN₅ Catalytic Sites Enable Efficient Peroxymonosulfate Activation by Forming Highly Reactive Mn(IV)–Oxo Species

Insights into O₂ Activation via Mn^IIIOOH Species on Mn-Rich Biochar

Merits and Limitations of Radical vs. Nonradical Pathways in Persulfate-Based Advanced Oxidation Processes

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Superoxide radical mediated Mn(III) formation is the key process in the activation of peroxymonosulfate (PMS) by Mn-incorporated bacterial-derived biochar

Cited by 79 publications

References 55 publications

Single-Atom MnN5 Catalytic Sites Enable Efficient Peroxymonosulfate Activation by Forming Highly Reactive Mn(IV)–Oxo Species

Single-Atom MnN5 Catalytic Sites Enable Efficient Peroxymonosulfate Activation by Forming Highly Reactive Mn(IV)–Oxo Species

Insights into O2 Activation via MnIIIOOH Species on Mn-Rich Biochar

Merits and Limitations of Radical vs. Nonradical Pathways in Persulfate-Based Advanced Oxidation Processes

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Single-Atom MnN₅ Catalytic Sites Enable Efficient Peroxymonosulfate Activation by Forming Highly Reactive Mn(IV)–Oxo Species

Single-Atom MnN₅ Catalytic Sites Enable Efficient Peroxymonosulfate Activation by Forming Highly Reactive Mn(IV)–Oxo Species

Insights into O₂ Activation via Mn^IIIOOH Species on Mn-Rich Biochar