Rapid and Highly Selective Fe(IV) Generation by Fe(II)-Peroxyacid Advanced Oxidation Processes: Mechanistic...

Area of Science:

• Environmental Chemistry
• Oxidation Chemistry
• Computational Chemistry

Background:

• High-valent iron species (Fe(IV/V/VI)) are effective in water decontamination.
• Conventional Fe(II)-activating oxidants like H2O2 and persulfate show slow reaction rates and low selectivity for Fe(IV) due to radical co-generation.

Purpose of the Study:

• To introduce peroxyacids (POAs) as novel, highly reactive Fe(II)-activating reagents.
• To investigate the mechanism and efficiency of Fe(II)-POA systems for water decontamination, specifically targeting bisphenol A (BPA).

Main Methods:

• Kinetic studies comparing Fe(II) reaction rates with POAs versus H2O2.
• Scavenging experiments using phenyl methyl sulfoxide (PMSO) and tert-butyl alcohol (TBA) to identify reactive species.
• Computational chemistry methods for thermodynamic evaluation of Fenton-like reaction pathways.

Main Results:

• POAs react with Fe(II) over 1000 times faster than H2O2, with high selectivity for Fe(IV) generation.
• Rapid degradation of bisphenol A (BPA) was achieved within one second using Fe(II)-POA systems.
• Fe(IV) was identified as the primary reactive species, with minor contributions from hydroxyl and peroxy radicals.

Conclusions:

• POAs are highly efficient and selective Fenton-like reagents for activating iron.
• The enhanced reactivity is attributed to lower energy barriers for O-O bond cleavage and favorable bidentate binding.
• This study provides a new avenue for water treatment technologies and highlights the utility of computational chemistry in understanding reaction mechanisms.