| 摘要: |
| 【目的】分析三维电极法去除氨氮的主要途径及其氧化机理。【方法】以石墨棒为阳极、不锈钢直筒为阴极、柱状活性炭为粒子电极，自制三维电极反应装置对废水中的氨氮进行处理，考察电解时间、电解电压、电解质（氯离子）浓度和pH值对氨氮去除效果的影响，并对氨氮的去除机理进行分析。【结果】在一定范围内，三维电极对氨氮的去除效果会随着电解电压、电解时间、电解质浓度的增大而上升；当电解电压为9 V，电解时间50 min，以 0.02 mol/L的NaCl作电解质，在废水pH呈中性时，三维电极反应装置对废水中氨氮的去除效果最好，去除率最高可达70%。通过试验数据及理论分析可知，氨氮的去除途径主要有2种：一是游离氨（NH3）在电极上直接氧化转化成N2；二是当体系中存在一定浓度的氯离子时，铵离子（NH4+）发生间接氧化反应生成N2。极少量亚硝氮和硝氮的生成表明体系内有少量的氨氮通过·OH、O3等中间氧化活性物质间接氧化。【结论】三维电极法在适宜条件下对废水中的氨氮有着良好的去除效果，并具有反应时间短和二次污染小等特点。 |
| 关键词: 氨氮 直接电化学氧化 间接电化学氧化 氯离子 |
| DOI： |
| 分类号: |
| 基金项目:陕西省科技统筹创新工程计划项目（2011KTZB03-03） |
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| Removal of ammonia nitrogen in wastewater by three dimensional electrode method |
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MU Tian,GUO Xinchao,SUN Changshun
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| Abstract: |
| 【Objective】This study investigated the main method to remove ammonia nitrogen and the oxidation mechanism using three dimensional electrode method. 【Method】Three dimensional electrode reactor was used to treat ammonia nitrogen in simulative domestic sewage with graphite as anode,stainless steel as cathode,and columnar activated carbon as particle electrode.Factors influencing removal rate of ammonia nitrogen (electrolysis time,voltage,concentration of electrolyte (chloride ions) and initial pH) were optimized and the removal mechanism was analyzed.【Result】With certain range,removal of ammonia nitrogen by three dimensional electrode was increased with the increase of electrolysis voltage,electrolysis time,and electrolyte concentration.The removal rate reached 70% under the optimal conditions of voltage 9 V,electrolysis time 50 min,sodium chloride 0.02 mol/L and neutral initial pH.There were mainly two pathways to remove ammonia nitrogen.One was free ammonia was converted to nitrogen gas by direct oxidization,while the other was ammonium ions were converted to nitrogen gas by indirect oxidization with chloride ions.Small amount of nitrite nitrogen and nitrate nitrogen were generated,indicating that partial ammonia nitrogen was indirectly oxidized by active oxide such as hydroxyl radical.【Conclusion】Three dimensional electrode method had good ammonia removal efficiency from wastewater under the suitable conditions with short reaction time and less secondary pollution. |
| Key words: ammonia nitrogen direct electrochemical oxidization indirect electrochemical oxidization chloride ion |
