电化学氧化法去除兰炭废水中COD和NH3-N  

Removing of COD and NH_(3)-N from blue-coke wastewater by electrochemical oxidation

作　　者：李金城 宋永辉[1] 汤洁莉[1] LI Jin-cheng;SONG Yong-hui;TANG Jie-li(Shaanxi Key Laboratory of Gold and Resource,Xi'an University of Architecture and Technology,Xi’an 710055,China)

机构地区：[1]西安建筑科技大学,陕西省黄金与资源重点实验室,陕西西安710055

出　　处：《中国环境科学》2022年第2期697-705,共9页China Environmental Science

基　　金：陕西省自然科学联合基金项目(2019JLM-44)。

摘　　要：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(NH_(3)-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NH_(3)-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NH_(3)-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Cl_(2)水解生成具有强氧化性的ClO^(-).电解过程中大部分NH_(3)-N在ClO^(-)的作用下转化为N_(2),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.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(NH_(3)-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 NH_(3)-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 NH_(3)-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 NH_(3)-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 N_(2)at 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.

关 键 词：电化学氧化 兰炭废水 COD NH_(3)-N 

分 类 号：X703[环境科学与工程—环境工程]