| Four electrodes:Ti/SnO2-Sb2O3/PbO2, Ti/SnO2-Sb2O3/Fe-PbO2, Ti/SnO2-Sb2O3/Co-PbO2 and Ti/SnO2-Sb2O3/Ni-PbO2 were prepared and characterized with X- ray diffraction (XRD), inductively coupled plasma emission spectroscopy (ICP) to evaluate the properties,the anodic oxygen evolution, chloride evolution and the electrode service-life testing. The electro-catalytic activity of our laboratory-made electrodes were explored through electro- catalytic degradation of ammonia-nitrogen simulated wastewater.The results show that in four electrodes prepared, Ti/SnO2-Sb2O3/Fe-PbO2 electrodes was an excellent anode material with high oxygen evolution potential, low chlorine evolution potential, the strong catalytic activity and low cell Voltage and long service life. The intermediate layer of the electrode contained tin and antimony oxides, the surface layer is a catalytic activity ofβ-PbO2, iron ion doped can increase the ability of electro-catalytic degradation.At the same time, the single influence factor of ammonia-nitrogen removal rate such as current density, temperature, pH, initial concentration of ammonia-nitrogen, concentration of chloride ion, plate space were investigated systematically. studies showed that the optimal operation conditions were that, a current density of 20mA·cm-2, a reaction temperature of 30℃, a pH of the weak alkaline (about 9.98), an initial ammonia-nitrogen concentration of 100 mg·L-1, a plate space of 1cm, and a chloride ion concentration of 1100 mg·L-1, ammonia-nitrogen removal rate can reach 100% and electro-catalytic degradation of ammonia-nitrogen in wastewater follows first order reaction kinetics.Orthogonal experimental of influence factors of ammonia-nitrogen and total nitrogen removal rates such as the current density, concentration of chloride ion, initial concentration of ammonia-nitrogen, pH, were also studied. It showed that ammonia electro-catalytic degradation of primary and secondary relationship of various factors as follows: initial pH value > initial concentration of ammonia > chloride ion concentration > current density. Effect of electro-catalytic degradation of total nitrogen of the primary and secondary factors as follows: the initial pH value > initial concentration of ammonia > current density >chloride ion concentration. Considering the removal rates of ammonia- nitrogen and total nitrogen, the optimum conditions were: pH value was alkaline, initial ammonia-nitrogen concentration was 100 mg·L-1, current density was 25 mA·cm-2, chloride ion concentration was 1100 mg·L-1. During Electro-catalytic degradation process, most of ammonia-nitrogen was degraded into N2, and nitrite generated took a small proportion of total nitrogen.With the anode of Ti/SnO2-Sb2O3/Fe-PbO2, electro-catalytic degradation of the actual printing and dyeing wastewater, after 5h, the ammonia nitrogen removal rate reached 100%, COD removal rate was55.62%, total nitrogen removal rate was 79.30%, The electrode was stable without dropping. |
