电化学/催化加氢工艺去除硝酸盐的动力学及机理

Reductive removal of nitrate by electrochemistry/catalytic hydrogenation coupling process: kinetics and mechanism

摘要:

为解决地下水硝酸盐（NO₃^--N）污染问题，采用电化学/催化加氢耦合工艺对其进行去除，重点考察该工艺对NO₃^--N的降解动力学及反应机理.结果表明，电化学/催化加氢耦合工艺在厌氧条件下能够在短时间内将NO₃^--N完全去除，去除速率（以N计）可达72.6 mg·L^-1·h^-1，反应符合二级反应动力学规律，常数k=0.005 5 cm²·mA^-1·min^-1.水中NO₃^--N一部分由电化学反硝化降解去除，另一部分由催化加氢还原去除，两种反应通过电解水产H₂反应耦联成为一个整体，宏观上符合电化学反硝化机理.

Abstract:

The kinetics and mechanism in the electrochemistry/catalytic hydrogenation (E/C) coupling process, which was employed to remove nitrate (NO₃^--N) from groundwater, was investigated in this paper. The results demonstrated that the NO₃^--N could be rapidly removed by E/C under anoxic conditions, and the degradation efficiency of NO₃^--N followed the increasing current density(I_D) with observed second order reaction rate and the constant(k) value of 0.005 5 cm²·mA^-1·min^-1. The NO₃^--N reductive by E/C with two kinds of reactions, electrochemistry denitrification and catalytic reduction, both of which aggregated by the reaction of brine electrolysis.