电化学氧化法去除兰炭废水中COD和NH3-N

采用电氯化氧化法处理高浓度含有机污染物和氨氮的兰炭废水，考查了NaCl添加量、外加电压、初始pH值等对废水中化学需氧量（COD）和氨氮（NH₃-N）去除效果的影响，并对电化学氧化过程及污染物氧化机理进行深入分析.研究表明，随着NaCl添加量、外加电压及电解时间的增加，废水中COD与NH₃-N去除率逐渐增大.在NaCl添加量为60g/L、电压6V、极板间距10mm、废水初始pH值不变、电解时间3h的条件下，兰炭废水中COD和NH₃-N去除率分别为84.31%和95.77%，远高于不添加NaCl时的41.18%和34.10%.废水中COD和氨氮的降解主要归因于间接氧化，阳极反应产生的Cl₂水解生成具有强氧化性的ClO^-.电解过程中大部分NH₃-N在ClO^-的作用下转化为N₂，而小部分以含氮化合物的形式存在.兰炭废水中有机污染物主要以酚类物质为主，电化学处理后其含量大幅降低，部分会转化为醚类或者烷烃类物质.

Removing of COD and NH3-N from blue-coke wastewater by electrochemical oxidation

Electro-chlorination and oxidation method was applied to treat the high concentration harmful components in blue-coke wastewater. The influence of dosage of sodium chloride bearing, external voltage, and initial pH on removal efficiency of chemical oxygen demand (COD) and ammonia nitrogen (NH₃-N) were investigated, the processing and pollutant oxidation mechanism of electrochemical oxidation were systematical analyzed. The results indicated that the removal efficiency of COD and NH₃-N both increased with the increasing of the addition of dosage of sodium chloride, applied voltage, and electrolysis time. Under the processing condition of sodium chloride 60g/L, voltage 6V, electrode distance 10mm, initial pH 9, and 3h electrolysis time, the COD and NH₃-N removal efficiency reached 84.31% and 95.77% respectively, which extremely exceeded the removal efficiency 41.18% and 34.10% without NaCl as the electrolyte. The degradation of COD and NH₃-N mainly depended on indirect oxidation of anode, the chlorine gas produced on the anode would occur hydrolysis reaction to produce active chlorine such as ClO^- in the solution. During electrolysis, most of ammonia nitrogen were converted to N₂at the action of ClO^-, and a small part existed in form of the compounds of containing nitrogen in the bulk solution. The major organic pollutants, phenolic substances in blue-coke wastewater decreased greatly after treatment, part of them could be converted into ethers or alkanes.