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

CNTs-Al was prepared by ball milling combined with sintering process and then used for CNTs-Al-Cu synthesis with chemical deposition method. The obtained CNTs-Al-Cu composite was systematically characterized and its NO-N reduction performance under alkaline condition was also evaluated. As indicated by the reduction batch experiment, 80.2% of NO-N removal efficiency was obtained in 90 min at pH of 9. The product of the reduction process was dominated by NO-N, which was further reduced to harmless N. The reusability of CNTs-Al-Cu composite was evaluated, and the experiment results showed that 68.1% of NO-N removal efficiency was maintained after 3 cycles of regeneration. Finally, based on the characterization results and kinetic analysis, it was concluded that micro-electrolysis was mainly responsible for the removal of NO-N by CNTs-Al-Cu.