Unveiling the Direct Electron Transfer Regime of Peracetic Acid Activation: Quantitative Structure–Activity Relationship Analysis of Carbon Nanotube Catalysis

Abstract

The demands for high-efficient and green activation of peracetic acid (PAA) have triggered research in exploring carbon catalysis. Nevertheless, the efforts in designing reaction-oriented and high-performance carbon catalysts are largely impeded by an ambiguous understanding of the fundamental carbon structure–PAA activation performance relationship. Herein, we investigated the quantitative structure–activity relationship (QSAR) of carbon nanotubes (CNTs) for PAA activation and micropollutant (MP) removal, by tuning the physiochemical properties of CNT via thermal annealing. The CNT/PAA system was dominated by the nonradical direct electron transfer (DET) oxidation pathway, showing high MP removal rates under complex water matrices. By conducting QSAR analysis, improved catalytic efficacy of the surface-regulated CNTs was attributed to the reinforced DET via the elevated oxidative potential of the CNT–PAA complex and the enhanced electrical conductivity of CNT. Furthermore, the larger specific surface area and lower oxygen content of CNT gave rise to the elevated oxidative potential of the CNT–PAA complex, while the electrical conductivity of CNT was positively correlated with the graphitization degree of CNT. Overall, this work sheds light on the influence cascade of the physicochemical properties of CNT for MP removal and PAA activation, providing guidelines for the fit-for-purpose design of the DET-mediated carbon catalysts for PAA oxidation.

Removal of Phenols by Highly Active Periodate on Carbon Nanotubes: A Mechanistic Investigation

“…Carbon nanotubes (CNTs), as an emerging carbon material, have recently received increasing attention for the abatement of aqueous pollutants. Several studies have shown that CNTs exhibit excellent activity toward various oxidants (e.g., permanganate, persulfate, peracetic acid). − Yun et al studied the activation of peroxydisulfate (PDS) by CNTs and found that CNTs could also activate PI . Despite some enlightening results on the system of PI activation by CNTs, the intrinsic nature of the oxidation process remains ambiguous.…”

Enhancing Fenton-like Degradation of Organic Pollutants at Neutral pH by Multivalent Cu NCs/HAp Nanocatalysts

“…Then, electrochemical analyses were conducted to elucidate the electron transfer process among Cu NCs/HAp, H 2 O 2 , and MB. It was observed that the addition of H 2 O 2 led to an increase in current density compared to the control group (Figure C,D), indicating the occurrence of electron transfer between 3-CuNCs/HAp and H 2 O 2 . , However, upon further addition of MB, it was inferred that there was no direct reaction between 3-Cu NCs/HAp and MB. Hence, it is likely that 1 O 2 and • OH originated from the transformation of • O 2 – and Cu 0 /Cu + /Cu 2+ in the Cu NCs/HAp + H 2 O 2 system.…”

Dual Nonradical Catalytic Pathways Mediated by Nanodiamond-Derived sp2/sp3 Hybrids for Sustainable Peracetic Acid Activation and Water Decontamination

“…Metal-free carbonaceous materials have emerged as promising alternatives in environmental catalysis to boost PAA activation by virtue of easy availability, high conductivity, and nontoxicity. To date, carbon nanotube, , reduced graphene oxide, activated carbon, − and biochar , have been adopted for PAA activation and displayed satisfactory reactivity in pollutant elimination via either a radical or nonradical pathway. However, there are still three challenging issues that need to be resolved.…”

“…For instance, several studies emphasized 1 O 2 as the primary contributor to pollutant oxidation according to the inhibition of pollutant degradation with the addition of common quenchers like furfuryl alcohol (FFA) and l -histidine ( l -his). However, these quenchers have been also reported to react with other reactive species such as the carbon-PAA complex , or directly react with PAA . (ii) The intrinsic active sites on carbon catalysts remain ambiguous due to the intricate carbon molecular structures and surface chemistry.…”

“…(ii) The intrinsic active sites on carbon catalysts remain ambiguous due to the intricate carbon molecular structures and surface chemistry. (iii) The PAA activation process dominated by the electron transfer process (ETP) or organic radical species (R-C • ) usually has poor stability of carbocatalysts and a narrow effective pH working window. , Thus, it is essential to engineer nanocarbons with precise active sites to coordinate on-demand reaction pathways with manipulated oxidation capacity and to possess structural robustness to resist oxidation during PAA activation.…”