Enhanced coagulation and oxidation by the Mn(VII)-Fe(III)/peroxymonosulfate process: Performance and mechanisms

Facile Pyrolysis Treatment for the Synthesis of Single-Atom Mn Catalysts Derived from a Hyperaccumulator

“…Quenching experiments based on EPR results were employed to further assess the contributions of different ROSs to CQP degradation, including MeOH for • OH and SO 4 •– , TBA for • OH, FFA, and NaN 3 for surface-bonding and 1 O 2 ROSs. , As displayed in Figure f, the CQP degradation rate was 31.15, 24.26, and 14.44% in the presence of 20 mM of MeOH, TBA, and FFA, respectively. This suggests that SO 4 •– and 1 O 2 play more important roles in CQP degradation than • OH and PMS activation. , Moreover, the generation of 1 O 2 in this system could also facilitate the formation of phenolic compounds and alleviate the side effects of chlorinated organic formation . This also suggests that ROS generation may occur almost simultaneously on the surface of SPBC-700N since the target organic pollutants would be adsorbed on the pyrrolic N sites that are close to the single-atom Mn–N 4 sites …”

“…•− and 1 O 2 play more important roles in CQP degradation than • OH and PMS activation. 37,38 Moreover, the generation of 1 O 2 in this system could also facilitate the formation of phenolic compounds and alleviate the side effects of chlorinated organic formation. 39 This also suggests that ROS generation may occur almost simultaneously on the surface of SPBC-700N since the target organic pollutants would be adsorbed on the pyrrolic N sites that are close to the single-atom Mn−N 4 sites.…”

Efficient pollutant degradation by peroxymonosulfate activated by a Co/Mn metal–organic framework

“…Additionally, Co 3+ /Mn 3+ could donate electrons to PMS to generate SO 5 ˙ − (eqn (2)). 47,48 Since the standard reduction potential of Co 3+ /Co 2+ ( E = 1.81 V) 49 was higher than that of Mn 3+ /Mn 2+ ( E = 1.51 V), 50 Mn 2+ might participate in the transformation of Co 3+ to Co 2+ (eqn (3)). Furthermore, the generated SO 4 ˙ − would react with H 2 O to form ˙OH, O 2 ˙ − and 1 O 2 .…”

Effect of a Permanganate-Bearing Reactive Oxidant on Flocs in Electrocoagulation: Transformations and Interfacial Interactions

“…It could be speculated that PM outcompeted dissolved oxygen in reacting with electrolytic Fe­(II) to form Fe­(III). Afterward, MnO 2 derived from PM further catalyzed the conversion of Fe­(II) to Fe­(III) species, and increased the particle concentration, ,, thus accelerating the formation of precipitates. Therefore, PM acted as an indirect catalyst for facilitating the coagulation process, which resulted in even a small amount of PM enhancing the formation of flocs.…”

“…Our previous study has shortened the start-up time of the coagulation process by introducing a reactive oxidant (permanganate, PM), which could react rapidly with Fe­(II) derived from the iron anode. In fact, it is common practice to enhance Fe-based coagulation by introducing PM, which is roughly attributed to the production of flocculation nuclei (manganese dioxide, MnO 2 ). − Moreover, during the complex redox reactions between the in situ formed Fe/Mn-based intermediates, inorganic- or organic-contaminants are removed through multiple pathways, such as adsorption, oxidation, co-precipitation, and so forth. ,− Despite this, the in-depth mechanism by which PM optimizes Fe-based coagulation or even EC has rarely been explored till date. Returning to the ECUF process, it is reported that the compact ECUF process outperformed the split EC-UF process in terms of membrane fouling control. , This was ascribed to the fact that from the macroscopic perspective, both the EC process and the electric field modulated the polarity and porosity of the cake layer, respectively. , Based on the ECUF process, the upgraded permanganate-bearing ECUF (PECUF) process was subsequently proposed due to its lower membrane fouling tendency, and higher working capacities, such as higher permeate flux, more effective contaminant removal, minimal secondary pollution, , and so forth.…”