Fenton-type process using peracetic acid: Efficiency, reaction elucidations and ecotoxicity

Area of Science:

• Environmental Chemistry
• Oxidation Processes
• Radical Chemistry

Background:

• Advanced oxidative processes (AOPs) are crucial for pollutant degradation.
• Peracetic acid (PAA) is an emerging oxidant in AOPs.
• Fenton-type processes utilize iron catalysts and oxidants.

Purpose of the Study:

• To investigate PAA-based Fenton-type reactions for dye degradation.
• To elucidate reaction mechanisms experimentally and theoretically.
• To assess the practical applicability and ecotoxicity of these processes.

Main Methods:

• Comparative study of PAA/Fe³⁺ and PAA/Fe²⁺ systems against the traditional Fenton process.
• Dye degradation efficiency assessment.
• Theoretical calculations (e.g., DFT) to determine reaction thermodynamics.
• Ecotoxicological testing using Dugesia tigrina.

Main Results:

• PAA/Fe³⁺ demonstrated higher dye degradation efficiency than the conventional Fenton process.
• PAA/Fe²⁺ showed comparable efficiency to the Fenton process.
• Photocatalysis with solar radiation enhanced efficiency via Fe³⁺ photoreduction.
• Theoretical calculations confirmed thermodynamic favorability of radical formation in PAA/Fe³⁺, but not in PAA/Fe²⁺.
• Ecotoxicity of PAA was linked to hydrogen peroxide (H₂O₂).

Conclusions:

• The PAA/Fe³⁺ system is a promising AOP for dye degradation due to spontaneous radical generation.
• The PAA/Fe²⁺ system is less suitable for practical applications.
• Solar-driven PAA/Fe³⁺ processes offer efficient degradation.
• Hydrogen peroxide is the primary contributor to PAA's observed toxicity.