Peroxymonosulfate Activation by Cobalt-Based Metal-Organic Framework for Rhodamine B Degradation

Area of Science:

• Materials Science
• Environmental Chemistry
• Catalysis

Background:

• Developing efficient photocatalysts for water purification is crucial for environmental remediation.
• Generating singlet oxygen (¹O₂) and superoxide radicals (O₂•⁻) is key for high photocatalytic performance.
• Metal-organic frameworks (MOFs) offer tunable structures for catalytic applications.

Purpose of the Study:

• To synthesize and evaluate a series of MOFs as peroxymonosulfate (PMS) activators for organic pollutant degradation.
• To investigate the catalytic activity and stability of MOFs {[MBPDC)]·H₂O}n (M = Fe²⁺, Co²⁺, Ni²⁺).
• To identify the primary reactive oxygen species responsible for pollutant degradation.

Main Methods:

• Synthesis of MOFs {[MBPDC)]·H₂O}n (M = Fe²⁺, Co²⁺, Ni²⁺).
• Photocatalytic degradation experiments using Rhodamine B (RhB) as a model pollutant.
• Radical scavenging tests and electron paramagnetic resonance (EPR) spectroscopy to identify reactive oxygen species.

Main Results:

• MOF 2 (Co²⁺-based) exhibited superior degradation efficiency, achieving 99.4% RhB removal in 12 minutes.
• MOF 2 demonstrated excellent reusability and structural stability over five cycles.
• Singlet oxygen (¹O₂) and superoxide radicals (O₂•⁻) were identified as the main reactive species.

Conclusions:

• MOF 2 is a highly efficient PMS activator for the regioselective oxidation of organic pollutants.
• The catalyst shows significant potential for cost-effective and robust environmental remediation.
• The study highlights the importance of MOFs in advanced oxidation processes for water treatment.