Stepwise H*-Mediated and Non-H* Reduction Processes for Highly Selective Transformation of Nitrate to Nitrogen Gas...

Area of Science:

• Environmental Chemistry
• Materials Science
• Electrochemistry

Background:

• Nitrate contamination poses environmental risks.
• Efficient nitrate reduction to nitrogen gas (N₂) is crucial for water remediation.
• Existing methods often lack selectivity or efficiency.

Purpose of the Study:

• To develop a novel material for highly selective nitrate reduction to N₂.
• To elucidate the reduction mechanism and the role of microenvironmental pH.
• To assess the material's performance in real wastewater.

Main Methods:

• Ternary ball-milled Al-Cu-AC material synthesis.
• Batch reduction experiments across a wide pH range.
• Analysis of reduction pathways and intermediates using electrochemical techniques.
• Copper leaching assessment.

Main Results:

• Al-Cu-AC (1:1:5) completely removed 30 mg/L NO₃^--N within pH 5-9.
• Achieved >83% total nitrogen (TN) removal and high N₂ selectivity.
• Identified atomic hydrogen (H*) and non-H* mediated pathways.
• Demonstrated no detectable copper leaching.
• Verified performance with actual wastewater.

Conclusions:

• The Al-Cu-AC material offers efficient and selective nitrate-to-N₂ reduction.
• Microenvironmental pH significantly influences electron-donating pathways.
• The material presents a promising approach for nitrate decontamination.