Were Persulfate-Based Advanced Oxidation Processes Really Understood? Basic Concepts, Cognitive Biases, and Experimental Details

Abstract

Persulfate (PS)-based advanced oxidation processes (AOPs) for pollutant removal have attracted extensive interest, but some controversies about the identification of reactive species were usually observed. This critical review aims to comprehensively introduce basic concepts and rectify cognitive biases and appeals to pay more attention to experimental details in PS-AOPs, so as to accurately explore reaction mechanisms. The review scientifically summarizes the character, generation, and identification of different reactive species. It then highlights the complexities about the analysis of electron paramagnetic resonance, the uncertainties about the use of probes and scavengers, and the necessities about the determination of scavenger concentration. The importance of the choice of buffer solution, operating mode, terminator, and filter membrane is also emphasized. Finally, we discuss current challenges and future perspectives to alleviate the misinterpretations toward reactive species and reaction mechanisms in PS-AOPs.

Direct Electron Transfer-Driven Nontoxic Oligomeric Deposition of Sulfonamide Antibiotics onto Carbon Materials for In Situ Water Remediation

“…However, the characteristic signal of 1 O 2 was not detected by ESR. The literature also reported that FFA could inhibit the electron transfer mechanism because the oxidation potential of FFA was weaker than the potential of catalyst/oxidant complex. , Thus, 1 O 2 was not generated in the system, and the electron transfer mechanism (ETP) might dominate the catalytic removal of the SAs. To further verify this hypothesis, a divided cell setup was employed to observe the current and voltage changes during the electron transfer process (Figure S34).…”