Ti/RuO_2-CoO电极制备及其氨氮降解性能

Preparation and Performance of Ti/RuO_2-CoO as Anode for the Degradation of Ammonia Nitrogen

采用热氧化法制备Ti/RuO_2-CoO电极,通过SEM和XRD对电极涂层的表面形貌和晶体结构进行表征;并利用最佳条件制备的电极开展电化学氧化氨氮模拟废水研究。实验研究了电流密度、初始pH值、Cl^-浓度和NH_3-N初始浓度对NH_3-N降解效果的影响。研究结果表明:当n(Ru)/n(Co)=7∶3时Ti/RuO_2-CoO电极对NH_3-N的去除效果较好。随着电流密度的增加,NH_3-N去除率随之升高;初始pH为碱性条件时,NH_3-N去除效果较好;NH_3-N去除率随Cl^-浓度的增加呈现先增大后减小,当Cl^-浓度为3 000 mg/L时,氨氮去除率达到97.95%。当电流密度为70 mA/cm^2、Cl^-浓度为3 000 mg/L、初始pH=9时,经过180 min电解后,氨氮初始浓度从500 mg/L降低至10.25 mg/L,且电化学氧化氨氮的产物主要为氮气和硝酸盐氮。

Ti/RuO2-CoO anode was prepared by thermal oxidation method and was used to treat simulated wastewater which contained ammonia nitrogen(NH3-N). The surface morphology and crystal structure of the electrode coating layer were analyzed by SEM and XRD. Effects of current density, initial pH, Cl- concentration and initial NH3-N concentration on removal efficiency of NH3-N using Ti/RuO2-CoO as anode were investigated.When n(Ru)/n(Co) was 7∶3, Ti/RuO2-CoO anode exhibited good performance on degradation of NH3-N. The increment of current density improved the removal rate of NH3-N. The removal efficiency of NH3-N was better in alkaline condition than that in acidic condition. The removal rate of NH3-N increased firstly and then decreased along with the increment of Cl- concentration. The NH3-N removal rate was 97.75% in the condition that Clconcentration was 3 000 mg/L. When the current density was 70 mA/cm2, Cl- concentration was 3 000 mg/L and the initial pH was 9, the NH3-N concentration was degraded from 500 mg/L to 10.25 mg/L in electrolysis time of180 min. Main products during electrochemical oxidation of NH3-N by Ti/RuO2-CoO anode were nitrogen and nitrate.