Densely Stacked CoCu-MOFs Coated with CuAl/LDH Enhance Sulfamethoxazole Degradation in PMS-Activated Systems

Area of Science:

• Environmental Chemistry
• Materials Science

Background:

• Sulfate radical-based advanced oxidation processes (SR-AOPs) are promising for refractory antibiotic degradation in wastewater.
• Systematic studies on potassium peroxymonosulfate (PMS) activation by MOF-derived metal oxides coated with layered double hydroxide (LDH) materials are limited.

Purpose of the Study:

• To synthesize and evaluate CoCu-MOFs coated with CuAl/LDH as catalysts for PMS activation.
• To investigate the removal efficiency and stability of the catalyst in degrading sulfamethoxazole (SMX).
• To elucidate the reaction mechanism and identify reactive species involved in SMX degradation.

Main Methods:

• Synthesis of CoCu-MOFs coated with CuAl/LDH.
• PMS activation for SMX degradation.
• Analysis of catalyst stability and metal leaching using ICP.
• Identification of reactive species (sulfate radicals, hydroxyl radicals, ¹O₂) and intermediates (LC/MS).
• XPS analysis to understand the catalyst's electronic structure and metal ion cycling.

Main Results:

• The CoCu/LDH catalyst achieved nearly 100% SMX removal and 53.7% mineralization within 60 minutes.
• The catalyst exhibited excellent stability with low metal leaching (Co: 0.013 mg/L, Cu: 0.313 mg/L).
• Sulfate radicals, hydroxyl radicals, and ¹O₂ were identified as key reactive species, indicating coupled radical and non-radical pathways.

Conclusions:

• The CoCu/LDH catalyst demonstrates high efficiency and stability for PMS activation in SMX removal.
• The layered structure facilitates metal ion cycling, promoting heterogeneous PMS activation.
• This work provides mechanistic insights into PMS activation catalysts for practical wastewater treatment applications.