Micro-electrolysis based nitrate reduction from aqueous solution by CNTs-Al-Cu composite under alkaline environment

Area of Science:

• Materials Science
• Environmental Chemistry
• Electrochemistry

Background:

• Nitrate nitrogen (NO₃^--N) contamination in water poses significant environmental and health risks.
• Developing efficient and reusable materials for nitrate removal is crucial for water purification.

Purpose of the Study:

• To synthesize and characterize a novel CNTs-Al-Cu composite.
• To evaluate the NO₃^--N reduction performance of the composite under alkaline conditions.
• To elucidate the mechanism responsible for nitrate removal.

Main Methods:

• Preparation of CNTs-Al-Cu composite using ball milling, sintering, and chemical deposition.
• Systematic characterization of the composite material.
• Batch experiments to assess NO₃^--N reduction efficiency and kinetics.
• Evaluation of composite reusability over multiple cycles.

Main Results:

• The CNTs-Al-Cu composite achieved 80.2% NO₃^--N removal efficiency within 90 minutes at pH 9.
• The primary reduction product was nitrite nitrogen (NO₂^--N), further reduced to nitrogen gas (N₂).
• The composite maintained 68.1% removal efficiency after three regeneration cycles, indicating good reusability.

Conclusions:

• The synthesized CNTs-Al-Cu composite is effective for alkaline NO₃^--N removal.
• Micro-electrolysis is identified as the primary mechanism driving the nitrate reduction process.
• The material shows potential for practical application in wastewater treatment.