New insight to superoxide radical-mediated degradation of pentachlorophenate: Kinetic determination and theoretical calculations

Bai, Lu; He, Lei; Fu, Yifu; Chu, Chu; Wei, Zongsu; Spinney, Richard; Dionysiou, Dionysios D.; Liang, Yanjie; Xiao, Ruiyang

doi:10.1039/d1cc06834b

Cited by 10 publications

(7 citation statements)

References 28 publications

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“…As such, both BMO-001-3A and BMO-001-3A-HNO 3 , modified with abundant surface-bridging hydroxyls, presented weaker electronegativity than BMO-001 and BMO-001-3A-KF. It is noticeable that NaPCP will dissociate into a negatively charged PCP – anion in water and engender an intensely repulsive force toward the negative interface . This repulsive force is not conducive to the NaPCP adsorption on BMO-001 with fairly strong electronegativity (Figure c).…”

Section: Resultsmentioning

confidence: 99%

“…It is noticeable that NaPCP will dissociate into a negatively charged PCP − anion in water and engender an intensely repulsive force toward the negative interface. 40 This repulsive force is not conducive to the NaPCP adsorption on BMO-001 with fairly strong electronegativity (Figure 2c). But the as-introduced surface hydroxyls of BMO-001-3A notably weakened its negative charge on the surface and thus effectively reduced the repulsion of NaPCP adsorption on the interface (Figure 2d).…”

Section: Bridging Hydroxyl-mediated Napcp Adsorptionmentioning

confidence: 98%

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Dual-Site Synergetic Photochemical Activation of Chlorinated Phenols Triggered by Surface Hydroxyls of Photocatalysts under Visible Light

Cui

Chen

et al. 2023

ACS Catal.

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In this study, abundant surface-bridging hydroxyls and terminal hydroxyls are deliberately and cyclically introduced in multiple photocatalysts via a facile hydrothermal method in ammonia for figuring out how these typical surface hydroxyls function in the photochemical decomposition process of chlorinated phenols (CPs). Experimental and theoretical results unveil that the photochemical reaction between CPs and surface hydroxyls is a dextrous pathway for the dechlorination and degradation of CPs on Bi2MoO6 as well as other similar metal oxide minerals. The bridging hydroxyls mainly serve as adsorption sites to capture CPs with the formation of adsorbed CP species (CPs*), while the adjacent terminal hydroxyls predominantly act as active sites and generate active hydroxyls to attack the CPs* under visible light. This dual-site synergetic activation triggered by surface hydroxyls markedly enhances the effective dechlorination and photochemical decomposition of CPs. This present work well extends the scope of the photochemical transformation process of CPs at a molecular level.

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Section: Resultsmentioning

confidence: 99%

Section: Bridging Hydroxyl-mediated Napcp Adsorptionmentioning

confidence: 98%

Dual-Site Synergetic Photochemical Activation of Chlorinated Phenols Triggered by Surface Hydroxyls of Photocatalysts under Visible Light

Cui

Chen

et al. 2023

ACS Catal.

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“…•− through measurements of second-order reaction rate constants. 18,19 Moreover, there have been studies questioning the important role of O 2…”

Section: Superoxide (Omentioning

confidence: 99%

“…Common quenchers of O 2 •– react more rapidly with hydroxyl radicals ( • OH) or hydrated electrons (e aq – ) (refer to Table S1). Some studies have also indicated the limited pollutant degradation capacity of O 2 •– through measurements of second-order reaction rate constants. , Moreover, there have been studies questioning the important role of O 2 •– in advanced oxidation processes such as catalytic ozonation and persulfate-based systems. , Therefore, it is necessary to reexamine the involvement of O 2 •– in pollutant reduction processes.…”

Section: Introductionmentioning

confidence: 99%

Identification of Superoxide Contribution through the Quenching Method and Model System

Cai,

Yao,

et al. 2024

ACS EST Eng.

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The quenching method is widely utilized to evaluate the contribution of reactive species; however, its validity has recently been questioned. The primary role of superoxide (O 2•− ) in pollutant degradation remains controversial due to its low reactivity. To ascertain the suitability of the quenching method and the degradation ability of O 2•− , a simple and efficient O 2generation system was built using p-benzoquinone (p-BQ) as the probe with disodium hydrogen phosphate−dimethyl sulfoxide (DHP−DMSO). The results demonstrated that O 2 •− is accountable for p-BQ transformation in DHP−DMSO, and can also be generated in various alkaline-organic solvent (methanol, ethanol, iso-propanol, tert-butanol, acetonitrile, acetone, chloroform, and tetrahydrofuran) systems, revealing that these reagents do not scavenge O 2•− . Superoxide dismutase has limited ability on O 2 •− quenching in the presence of hydroxyl radicals ( • OH). Some organic solvents can produce organic radicals when stimulated by • OH. This serves as a reminder to exercise caution when employing these quenchers. O 2•− exhibited insufficient degradation capability for the majority of the eight organic pollutants tested. The relevance of O 2•− in pollutant degradation can be quickly discerned by DHP−DMSO. This study holds significant importance in accurately evaluating the contribution of reactive species.

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“…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.

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129

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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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New insight to superoxide radical-mediated degradation of pentachlorophenate: Kinetic determination and theoretical calculations

Abstract: This study reported the reactivity and mechanisms of superoxide radical (O2•-)-mediated transformation of pentachlorophenol. Our results indicated that O2•- alone exhibits limited effects on its degradation, and bimolecular nucleophilic substitution...

Cited by 10 publications

References 28 publications

Dual-Site Synergetic Photochemical Activation of Chlorinated Phenols Triggered by Surface Hydroxyls of Photocatalysts under Visible Light

Dual-Site Synergetic Photochemical Activation of Chlorinated Phenols Triggered by Surface Hydroxyls of Photocatalysts under Visible Light

Identification of Superoxide Contribution through the Quenching Method and Model System

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

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