Engineering Electrode Polarity for Enhancing In Situ Generation of Hydroxyl Radicals Using Granular Activated Carbon

Area of Science:

• Environmental Chemistry
• Materials Science
• Electrochemistry

Background:

• Granular activated carbon (GAC) is effective for in situ reactive oxygen species (ROS) generation.
• Electrochemical methods are crucial for advanced oxidation processes in water treatment.

Purpose of the Study:

• To enhance H2O2 decomposition via 2-electron oxygen reduction reaction (2e-ORR) using electrochemically modified GAC.
• To optimize electrode polarity reversal (PR) parameters for increased hydroxyl radical (•OH) generation.
• To evaluate the efficacy of the modified GAC for glyphosate removal.

Main Methods:

• Electrochemical modification of GAC using electrode polarity reversal (PR).
• Optimization of PR parameters: frequency, current intensity, and time intervals.
• Quantification of •OH concentration using optimized parameters.
• Assessment of glyphosate removal efficiency using modified and unmodified GAC.

Main Results:

• Optimized PR enhanced GAC hydrophilicity by increasing surface oxygen functionalities.
• Optimized electrode polarity reversal (20 (No PR)-2 (PR) interval, 140 mA) yielded a •OH concentration of 38.9 μM.
• The modified GAC removed 67.6% of glyphosate, significantly higher than unmodified GAC (40.6%).

Conclusions:

• Electrochemical modification of GAC via PR is a viable strategy for enhancing ROS synthesis.
• The optimized GAC cathode shows significant potential for improving the efficiency of electrochemical water treatment systems.
• This approach offers a pathway to more effective removal of persistent organic pollutants from water.