Reaction Pathway Tuning between Electron Transfer-Mediated Degradation and Polymerization in Fe-MoS₂-Based Persulfate...

Area of Science:

• Environmental Chemistry
• Materials Science
• Catalysis

Background:

• Persulfate-based advanced oxidation processes (AOPs) are crucial for removing organic pollutants.
• These AOPs can follow electron transfer-based degradation or polymerization pathways.
• Understanding and controlling these pathways, especially concerning oxidant dosage, is critical but underexplored.

Purpose of the Study:

• To investigate the Fe-doped MoS2/peroxydisulfate (PDS) system for phenolic compound (PC) removal.
• To elucidate the influence of oxidant dosage on the reaction pathway (mineralization vs. polymerization).
• To identify phenolic compounds prone to polymerization.

Main Methods:

• Utilized an Fe-doped MoS2 catalyst activated by PDS for PC degradation.
• Analyzed reaction pathways under varying PDS dosages.
• Correlated PC structure and adsorption properties with polymerization tendency.

Main Results:

• The Fe-MoS2/PDS system effectively removes PCs via a high-valent iron pathway.
• Oxidant dosage critically influences the reaction pathway: low PDS favors polymerization, high PDS favors electron transfer degradation.
• Phenolic compounds like DMP, MOP, MP, MeP, and NP showed a high polymerization trend due to easier adsorption of their products on the catalyst.

Conclusions:

• Polymerization is a prevalent process in PDS activation systems.
• Oxidant dosage and the specific type of phenolic compound significantly impact the transformation between degradation and polymerization pathways.
• This work provides insights into controlling AOP reaction pathways for optimized pollutant removal.