Degradation of Diclofenac by Loaded Solid Superbase-Activated Persulfate

Area of Science:

• Environmental Chemistry
• Materials Science

Background:

• Alkali-activated persulfate (PS) is crucial for in situ chemical oxidation.
• Innovation in alkali activation methods for PS is limited.

Purpose of the Study:

• To develop and evaluate novel supported solid superbases for activating persulfate.
• To investigate the degradation of diclofenac (DCF) using these novel catalysts.

Main Methods:

• Preparation of two supported solid superbases: KNO3/γ-Al2O3 (KAl) and KNO3/SBA-15/MgO (KSM).
• Activation of persulfate by KAl and KSM for diclofenac degradation.
• Analysis of reaction mechanisms, including radical identification and intermediate product determination.

Main Results:

• Both KAl and KSM effectively elevated solution pH, catalyzing PS to degrade DCF above pH 10.5.
• KSM exhibited the highest catalytic efficiency, comparable to sodium hydroxide.
• Identified hydroxyl, sulfate, and superoxide radicals, with hydroxyl playing a key role. Proposed six degradation pathways and five intermediates.

Conclusions:

• Supported solid superbases, particularly KSM, offer an efficient and innovative method for PS activation in DCF degradation.
• The mechanism involves pH elevation and potential formation of K2O2, alongside radical species.
• Understanding degradation pathways and byproducts is crucial for environmental applications.