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Mai J, Zeng G, Jiang M, Su P, Lv Q, Li W, Hou X, Liu M, Ma J, Yang T. Unraveling the role of Mn(V)/Mn(III) in the enhanced permanganate oxidation under Vis-LED radiation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 944:173655. [PMID: 38848904 DOI: 10.1016/j.scitotenv.2024.173655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 05/14/2024] [Accepted: 05/28/2024] [Indexed: 06/09/2024]
Abstract
A novel approach of visible light-emitting diode (Vis-LED) radiation was employed to activate permanganate (Mn(VII)) for efficient organic micropollutant (OMP) removal. The degradation rates of OMPs by Vis-LED/Mn(VII) were 2-5.29 times higher than those by Mn(VII) except for benzoic acid and atrazine. Increasing wavelengths (445-525 nm) suppressed the degradation of diclofenac (DCF) and 4-chlorophenol (4-CP) owing to the decreased quantum yields of Mn(VII). Comparatively, light intensity and Mn(VII) dosage had a positive effect on the degradation of DCF and 4-CP. Experimental data revealed that Mn(V) dominated the DCF degradation whereas Mn(III) was the active oxidant in the 4-CP degradation. Mn(V) and Mn(III) formed from the photo-decomposition of Mn(VII), meanwhile, Mn(III) also formed from the Mn(V) photo-decomposition. The increase in solution pH inhibited DCF degradation but had a positive impact on 4-CP degradation, mainly due to the changing speciation of DCF and 4-CP. Inorganic anions (Cl- and HCO3-) had little impact on DCF and 4-CP degradation, while humic acid (HA) showed a positive impact because of the π-π interaction between HA and DCF/4-CP. The transformation products of DCF and 4-CP were identified and transformation pathways were proposed. Finally, the Vis-LED/Mn(VII) exhibited great degradation performance in various authentic waters. Overall, this study boosts the development of Mn(VII)-based oxidation processes.
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Affiliation(s)
- Jiamin Mai
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Ge Zeng
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Maoju Jiang
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Peng Su
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Qixiao Lv
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Wenqi Li
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Xiangyang Hou
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Minchao Liu
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Jun Ma
- State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China
| | - Tao Yang
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China; Institute of Carbon Peaking and Carbon Neutralization, Wuyi University, Jiangmen 529020, Guangdong Province, China; Guangdong Laboratory of Chemistry and Fine Chemical Industry Jieyang Center, Jieyang 515200, China.
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Yang T, Mai J, Zhu M, Peng Q, Huang C, Wu S, Tan Q, Jia J, Fang J, Ma J. Enhanced Permanganate Activation under UVA-LED Irradiation: Unraveled Mechanism Involving Manganese Species and Hydroxyl Radical. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:17720-17731. [PMID: 36469811 DOI: 10.1021/acs.est.2c06290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Permanganate [Mn(VII)] has gained broad attention in water treatment. However, its limited reactivity toward some refractory micropollutants hinders its application for micropollutant degradation. Herein, we introduced UVA-LED photolysis of Mn(VII) (UVA-LED/Mn(VII)) to degrade micropollutants (diclofenac (DCF), 4-chlorophenol (4-CP), atrazine, and nitrobenzene) by selecting DCF and 4-CP as target micropollutants. The effects of operating conditions (e.g., light intensity, radiation wavelengths, pH, and water constituents) on DCF and 4-CP degradation as well as the underlying mechanisms were systematically studied. The degradation rates of DCF and 4-CP linearly decreased with increasing radiation wavelengths (from 365 to 405 nm), likely due to the decreased molar absorption coefficients and quantum yields of Mn(VII). Reactive manganese species (RMnS), including Mn(V), Mn(III), and HO•, were generated in the UVA-LED/Mn(VII) process. Mn(V) and HO• were responsible for DCF degradation, while Mn(III), HO•, and likely Mn(V) accounted for 4-CP degradation. Competitive kinetic results revealed that contributions of RMnS and HO• decreased with increasing radiation wavelengths, wherein RMnS played the dominant role. Increasing pH displayed opposite effects on DCF and 4-CP degradation with higher degradation efficiency obtained at acidic pH for the former one but alkaline pH for the latter one. The presence of water background ions (e.g., Cl-, HCO3-, and Ca2+) barely influenced DCF and 4-CP degradation. Finally, in comparison with Mn(VII) alone, enhanced degradation of DCF and 4-CP by UVA-LED/Mn(VII) was observed in real waters. This work advances the understanding of the photochemistry of manganese species in micropollutant degradation and facilitates Mn(VII) oxidation in practical application.
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Affiliation(s)
- Tao Yang
- School of Biotechnology and Health Science, Wuyi University, Jiangmen 529020, Guangdong, China
| | - Jiamin Mai
- School of Biotechnology and Health Science, Wuyi University, Jiangmen 529020, Guangdong, China
| | - Mengyang Zhu
- School of Biotechnology and Health Science, Wuyi University, Jiangmen 529020, Guangdong, China
| | - Qiqi Peng
- School of Biotechnology and Health Science, Wuyi University, Jiangmen 529020, Guangdong, China
| | - Cui Huang
- School of Biotechnology and Health Science, Wuyi University, Jiangmen 529020, Guangdong, China
| | - Sisi Wu
- School of Biotechnology and Health Science, Wuyi University, Jiangmen 529020, Guangdong, China
| | - Qinying Tan
- School of Biotechnology and Health Science, Wuyi University, Jiangmen 529020, Guangdong, China
| | - Jianbo Jia
- School of Biotechnology and Health Science, Wuyi University, Jiangmen 529020, Guangdong, China
| | - Jingyun Fang
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China
| | - Jun Ma
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
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Sen A, Kumar R, Rajaraman G. A theoretical perspective on the reactivity of high-valent Mn-Oxo/nitrene species towards oxidative transformations. Inorganica Chim Acta 2022. [DOI: 10.1016/j.ica.2021.120654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Kumar R, Pandey B, Singh A, Rajaraman G. Mechanistic Insights into the Oxygen Atom Transfer Reactions by Nonheme Manganese Complex: A Computational Case Study on the Comparative Oxidative Ability of Manganese-Hydroperoxo vs High-Valent Mn IV═O and Mn IV-OH Intermediates. Inorg Chem 2021; 60:12085-12099. [PMID: 34293860 DOI: 10.1021/acs.inorgchem.1c01306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Understanding the comparative oxidative abilities of high-valent metal-oxo/hydroxo/hydroperoxo species holds the key to robust biomimic catalysts that perform desired organic transformations with very high selectivity and efficiency. The comparative oxidative abilities of popular high-valent iron-oxo and manganese-oxo species are often counterintuitive, for example, oxygen atom transfer (OAT) reaction by [(Me2EBC)MnIV-OOH]3+, [(Me2EBC)MnIV-OH]3+, and [(Me2EBC)MnIV═O]2+ (Me2EBC = 4,11-dimethyl-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane) shows extremely high reactivity for MnIV-OOH species and no reactivity for MnIV-OH and MnIV═O species toward alkyl/aromatic sulfides. Using a combination of density functional theory (DFT) and ab initio domain-based local pair natural orbital coupled-cluster with single, double, and perturbative triples excitation (DLPNO-CCSD(T)) and complete-active space self-consistent field/N-electron valence perturbation theory second order (CASSCF/NEVPT2) calculations, here, we have explored the electronic structures and sulfoxidation mechanism of these species. Our calculations unveil that MnIV-OOH reacts through distal oxygen atom with the substrate via electron transfer (ET) mechanism with a very small kinetic barrier (16.5 kJ/mol), placing this species at the top among the best-known catalysts for such transformations. The MnIV-OH and MnIV═O species have a much larger barrier. The mechanism has also been found to switch from ET in the former to concerted in the latter, rendering both unreactive under the tested experimental conditions. Intrinsic differences in the electronic structures, such as the presence and absence of the multiconfigurational character coupled with the steric effects, are responsible for such variations observed. This comparative oxidative ability that runs contrary to the popular iron-oxo/hydroperoxo reactivity will have larger mechanistic implications in understanding the reactivity of biomimic catalysts and the underlying mechanisms in PSII.
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Affiliation(s)
- Ravi Kumar
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Bhawana Pandey
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Akta Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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Structural Basis for Selective Oxidation of Phosphorylated Ethylphenols by Cytochrome P450 Monooxygenase CreJ. Appl Environ Microbiol 2021; 87:AEM.00018-21. [PMID: 33712426 DOI: 10.1128/aem.00018-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 03/04/2021] [Indexed: 11/20/2022] Open
Abstract
Selective oxidation of C-H bonds in alkylphenols holds great significance for not only structural derivatization in pharma- and biomanufacturing but also biological degradation of these toxic chemicals in environmental protection. A unique chemomimetic biocatalytic system using enzymes from a p-cresol biodegradation pathway has recently been developed. As the central biocatalyst, the cytochrome P450 monooxygenase CreJ oxidizes diverse p- and m-alkylphenol phosphates with perfect stereoselectivity at different efficiencies. However, the mechanism of regio- and stereoselectivity of this chemomimetic biocatalytic system remained unclear. Here, using p- and m-ethylphenol substrates, we elucidate the CreJ-catalyzed key steps for selective oxidations. The crystal structure of CreJ in complex with m-ethylphenol phosphate was solved and compared with its complex structure with p-ethylphenol phosphate isomer. The results indicate that the conformational changes of substrate-binding residues are slight, while the substrate promiscuity is achieved mainly by the available space in the catalytic cavity. Moreover, the catalytic preferences of regio- and stereoselective hydroxylation for the two ethylphenol substrates is explored by molecular dynamics simulations. The ethyl groups in the complexes display different flexibilities, and the distances of the active oxygen to H pro-S and H pro-R of methylene agree with the experimental stereoselectivity. The regioselectivity can be explained by the distances and bond dissociation energy. These results provide not only the mechanistic insights into CreJ regio- and stereoselectivity but also the structural basis for further P450 enzyme design and engineering.IMPORTANCE The key cytochrome P450 monooxygenase CreJ showed excellent regio- and stereoselectivity in the oxidation of various alkylphenol substrates. C-H bond functionalization of these toxic alkylphenols holds great significance for both biological degradation of these environmental chemicals and production of value-added structural derivatives in pharmaceutical and biochemical industries. Our results, combined with in vitro enzymatic assays, crystal structure determination of enzyme-substrate complex, and molecular dynamics simulations, provide not only significant mechanism elucidation of the regio- and stereoselective catalyzation mediated by CreJ but also the promising directions for future engineering efforts of this enzyme toward more useful products. It also has great extendable potential to couple this multifunctional P450 enzyme with other biocatalysts (e.g., hydroxyl-based glycosylase) to access more alkylphenol-derived high-value chemicals through environment-friendly biocatalysis and biotransformation.
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Kumar R, Ansari A, Rajaraman G. Axial vs. Equatorial Ligand Rivalry in Controlling the Reactivity of Iron(IV)-Oxo Species: Single-State vs. Two-State Reactivity. Chemistry 2018; 24:6818-6827. [DOI: 10.1002/chem.201800380] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Ravi Kumar
- Department of Chemistry; Indian Institute of Technology Bombay; Powai, Mumbai 400076 India
| | - Azaj Ansari
- Department of Chemistry; Central University of Haryana; Haryana 123031 India
| | - Gopalan Rajaraman
- Department of Chemistry; Indian Institute of Technology Bombay; Powai, Mumbai 400076 India
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Ansari A, Ansari M, Singha A, Rajaraman G. Interplay of Electronic Cooperativity and Exchange Coupling in Regulating the Reactivity of Diiron(IV)-oxo Complexes towards C−H and O−H Bond Activation. Chemistry 2017; 23:10110-10125. [DOI: 10.1002/chem.201701059] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Azaj Ansari
- Department of Chemistry; CUH Haryana; Haryana 123031 India
| | | | - Asmita Singha
- Department of Chemistry; IIT Bombay; Mumbai 400076 India
| | - Gopalan Rajaraman
- Department of Chemistry; Indian Institute of Technology Bombay, Powai; Mumbai, Maharashtra 400076 India
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Jayapal P, Ansari A, Rajaraman G. Computational Examination on the Active Site Structure of a (Peroxo)diiron(III) Intermediate in the Amine Oxygenase AurF. Inorg Chem 2015; 54:11077-82. [PMID: 26588098 DOI: 10.1021/acs.inorgchem.5b00872] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In this work, we report the first computational investigation on the structure and properties of the (peroxo)diiron(III) intermediate of the AurF enzyme. Our calculations predict that, in the oxidized state of the AurF enzyme, the peroxo ligand is depicted in a μ-1,1-coordination mode with a protonated bridging ligand and is not in a μ-η(2):η(2) or μ-1,2 mode. Computed spectral data for the μ-1,1-coordination mode correlate well with experimental observations and unravel the potential of the energetics-spectroscopic approach adapted here.
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Affiliation(s)
- Prabha Jayapal
- Department of Chemistry, Indian Institute of Technology Bombay , Mumbai 400076, India
| | - Azaj Ansari
- Department of Chemistry, Indian Institute of Technology Bombay , Mumbai 400076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay , Mumbai 400076, India
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