Low Concentration of Peroxymonosulfate Triggers Dissolved Oxygen Conversion over Single Atomic Fe–N₃O₁ Sites for Water Decontamination

Abstract

Achieving satisfactory organic pollutant oxidation with a low concentration of peroxymonosulfate (PMS) is vital for persulfate‐involved advanced oxidation processes to reduce resource consumption and avoid excessive sulfate anion (SO42−) production. Herein, efficient conversion of dissolved oxygen (DO) over single‐atomic Fe–N3O1 sites anchored on carbon nitride for efficient contaminant degradation is fulfilled, triggered by a low concentration of PMS (0.2 mm). Experimental and theoretical results reveal that the preferentially adsorbed PMS onto atomic Fe–N3O1 center can deliver electrons toward the single Fe atom to increase its electron density to trigger DO reduction into superoxide radical (O2• −) and successive transformation into singlet oxygen (1O2), which is quite different from the conventional PMS activation process mostly depending on PMS itself function for reactive oxygen species generation. On the other hand, PMS with high concentration could occupy active Fe–N3O1 sites to hamper DO conversion and further produce massive SO42−. A couple of ‐Fe‐CN0.05 ‐and slight PMS is effective for actual kitchen wastewater remediation and long‐term bisphenol A degradation. This work elucidates the triggering role of low‐concentration PMS in DO conversion over a single‐atom Fe catalyst, which can inspire the development of resource‐saving, cost‐effective, and environmentally‐friendly catalytic oxidation systems for environmental restoration.

Electron Delocalization Realizes Speedy Fenton‐Like Catalysis over a High‐Loading and Low‐Valence Zinc Single‐Atom Catalyst

“…•can interact with NBT to weaken the maximum absorbance of NBT at 259 nm. [37,38] As depicted in Figure 4d, the maximum absorption intensity of NBT undergoes a decrease after interacting with Zn SA -N-C for 30 min, confirming the O 2…”

“…To validate the yield of O 2 ●‒ over Zn SA ‐N‐C, the nitroblue tetrazolium (NBT) method was adopted since O 2 ●‒ can interact with NBT to weaken the maximum absorbance of NBT at 259 nm. [ 37,38 ] As depicted in Figure 4d, the maximum absorption intensity of NBT undergoes a decrease after interacting with Zn SA ‐N‐C for 30 min, confirming the O 2 ●‒ generation over Zn SA ‐N‐C via DO reduction. The attenuation of NBT absorbance continues to proceed upon the addition of BPA into the Zn SA ‐N‐C suspension, while the infusion of PDS reduces the NBT absorption intensity, which symbolizes the promotion and demotion of DO reduction over Zn SA ‐N‐C by BPA and PDS, respectively.…”

eg Orbital Occupancy-Dependent Intrinsic Catalytic Activity of Zn–Co–Mn Spinel Oxides in Fenton-like Reactions

“…Unexpectedly, the generation of O 2 •– is due to the reduction of dissolved oxygen over the Mn Oh 3+ -containing catalyst surface (a detailed discussion on the origin of O 2 •– is presented in Text S6 accompanying Figures S31–S33). TEMP- 1 O 2 is detected in all systems since it can be generated via the recombination or disproportion of O 2 •– , hydrolysis of SO 5 •– , and self-decomposition of PMS in water (Figure S34). By virtue of in situ Raman, the role of PMS* in ZnMn 2 O 4 /PMS and ZnCoMnO 4 /PMS systems is identified.…”

“…•− is presented in Text S6 accompanying Figures S31−S33). 37 TEMP-1 O 2 is detected in all systems since it can be generated via the recombination or disproportion of O 2…”

Applications of Carbon‐Based Materials in Activated Peroxymonosulfate for the Degradation of Organic Pollutants: A Review

“…In the work of Zhao et al., DO can accept electrons from the electron‐rich Fe center and reduce to O 2 ⋅ − , which is then converted to 1 O 2. [197] The oxidation process can be carried out under low PMS conditions to degrade organic pollutants with high efficiency, which not only saves resources, but also avoids the generation of a large amount of SO 4 2− during the reaction process. In addition, DO can also facilitate the process of PMS catabolism to promote the production of ROS.…”