滤压式电解槽中氨氮间接电氧化反应动力学

A Kinetics of Indirect Electro-oxidation Reation of NH_3-N with Chloride Ion in a Filter-press Type Electrochemical Cell

研究了模拟氨氮废水在滤压式电解槽中的电化学氧化过程.结果表明,在一定浓度Cl-的存在下,氨氮化合物的间接电氧化过程符合二级反应动力学规律.利用Hatta准数进一步分析电解槽内反应的空间分布得知,不同条件下的Hatta准数均小于0.3,这说明氨氮化合物的间接电氧化过程主要发生在慢反应动力学区域,即发生在本体溶液中.

Indirect electro-oxidation of the simulated wastewater containing ammonia-N in a filter press-type electrochemical cell was studied. The process obeys a second order reaction kinetics with a certain concentration of chlorine ion, when the concentration of NH3-N is equivalent of/to the one of electro-generated active chlorine. The cell performance is influenced significantly by the operating conditions including current density, flow rate and initial concentration of NH3-N. The results show that the best optimum operating condition is electrolyte flow rate of 60 L/h and current density of 60 mA/cm^2 in slightly alkaline （pH = 8.0） solution with 0. 1 mol/L NaCl and 1 mol/L Na2SO4 as a supporting electrolyte at 25 ℃, and kinetic rate constant k2 = 3.23×10^-5 m^3/（ tool·s）. The information about the spatial distribution of the reactions may be obtained from the Hatta number. The value of the Hatta number （ 〈 0.3 ）, estimated under different operation conditions, implies that most of the reaction of the ammonia with active chlorine occurred in the bulk solution, which provided the effective information to design the electrochemical cell.