| A new method based on electrochemistry was presented to treat NO-3-N wastewater by analyzing theories of Pd-Me bimetal catalytic reduction of NO-3-N and NH+4-N break point chlorination process. Presented method mainly includes following characteristics. Firstly, NO-3-N can be catalytically reduced in electric field while Ti substrate cathode was modified by common metallic elements which have empty electronic track. Secondly, NO-3-N reduction product can be controlled mainly is NH+4-N by adjusting ratio of catalytic elements and electrolysis conditions. Finally, NH+4-N is oxidized to harmless product N2-N by HOCl which produced from Cl- by anode oxidation process. Experiments were carried out to verified upwards theoretical assumptions. It’s indicated that cathode modified by metal elements of Co and Cu can catalytic reduce NO-3-N in simulated wastewater effectively, as well as reduction product mainly was NH+4-N while the molar ratio of Co and Cu in cathode precursor solution was 1∶1. If Cl- was added to electrolysis system, NH+4-N produced from NO-3-N reduction could be oxidized to N2-N by the anode action. Under the conditions of plate distance of 6mm, electric current of 400 mA and electrolysis time of 2.5h, the concentration of NO-3-N, NO-2-N, NH+4-N, and TN of simulated wastewater which initially contain 100 mg/L NO-3-N and 1000 mg/L Cl- decreased to 2.9 mg/L, 0.5 mg/L, 1.7 mg/L and 6.0 mg/L respectively. |
