Peracetic acid (PAA) serves as a potent and lowtoxic oxidant for contaminant removal. Radical-mediated catalytic PAA oxidation processes are typically non-selective, rendering weakened oxidation efficacy under complex water matrices. Herein, we explored the usage of reduced graphene oxide (rGO) for PAA activation via a non-radical pathway. Outperforming the most catalytic PAA oxidation systems, the rGO−PAA system exhibits near-complete removal of typical micropollutants (MPs) within a short time (<2 min). Non-radical direct electron transfer (DET) from MPs to PAA plays a decisive role in the MP degradation, where accelerated DET is achieved by a higher potential of the rGO−PAA reactive surface complexes. Benefitting from DET, the rGO−PAA system shows robust removal of multiple MPs under complex water matrices and with low toxicity. Notably, in the DET regime, the electrostatic attraction of rGO to both PAA and target MP is a critical prerequisite for achieving efficient oxidation, depending on the conditions of solution pH and MP pK a . A heatmap model building on such an electrostatic interaction is further established as guidance for regulating the performance of the DET-mediated PAA oxidation systems. Overall, our work unveils the imperative role of DET for rGO-activated PAA oxidation, expanding the knowledge of PAA-based water treatment strategies.
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.
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