Harnessing air-water interface to generate interfacial ROS for ultrafast environmental remediation

Area of Science:

• Environmental Chemistry
• Catalysis
• Surface Science

Background:

• The air-water interface of microbubbles is a unique microenvironment for accelerating reactive oxidative species (ROS) reactions.
• Probing interfacial ROS is challenging due to the dynamic nature of microbubbles, limiting understanding and applications.

Purpose of the Study:

• To develop a method for investigating interfacial ROS at microbubble surfaces.
• To enhance ROS generation and reactivity at the air-water interface.

Main Methods:

• Coupling microbubbles with a Fenton-like reaction.
• Utilizing an amphiphilic single-cobalt-atom catalyst (Co@SCN) to transport peroxymonosulfate (PMS) to the interface.
• Investigating the concentration and reactivity of interfacial sulfate radicals (SO₄^•-).

Main Results:

• Achieved a 20-fold higher concentration of interfacial SO₄^•- (4.48 × 10^-11 M) compared to bulk.
• Demonstrated preferential localization of SO₄^•- at the air-water interface due to low free energy and hydrogen bonding.
• Observed over 100-fold greater oxidation reactivity of interfacial SO₄^•- toward toluene (rate constant of 10¹⁰ M^-1 s^-1).

Conclusions:

• Developed a strategy to accelerate ROS reactions at the air-water interface using microbubbles.
• Highlighted the significance of interfacial ROS for enhanced chemical reactivity.
• Showcased potential applications in pollutant degradation and other interfacial reactions.