孙拓,李一兵,张汝山,冒冉,王开丰,刘新兵,郭聪慧,赵旭.硝酸盐废水的连续流电催化脱氮研究[J].环境科学学报,2021,41(7):2806-2813
硝酸盐废水的连续流电催化脱氮研究
- Continuous electrocatalytic denitrification of nitrate wastewater
- 基金项目：国家自然科学基金（No.51808535）；北京市自然科学基金（No.8184088）
- 孙拓
- 1. 河北工业大学, 土木与交通学院, 天津 300401;2. 中国科学院生态环境研究中心, 中国科学院饮用水科学与技术重点实验室, 北京 100085
- 李一兵
- 河北工业大学, 土木与交通学院, 天津 300401
- 冒冉
- 中国科学院生态环境研究中心, 中国科学院饮用水科学与技术重点实验室, 北京 100085
- 王开丰
- 中国科学院生态环境研究中心, 中国科学院饮用水科学与技术重点实验室, 北京 100085
- 郭聪慧
- 1. 河北工业大学, 土木与交通学院, 天津 300401;2. 中国科学院生态环境研究中心, 中国科学院饮用水科学与技术重点实验室, 北京 100085
- 赵旭
- 中国科学院生态环境研究中心, 中国科学院饮用水科学与技术重点实验室, 北京 100085
- 摘要：以高效阴极和形稳阳极为基础构建了电催化同步氧化还原脱氮体系，在还原硝酸盐的同时实现总氮的去除.同时，以电镀锌酸洗废水为例进行了连续流电化学脱氮研究，考察了电流密度和水力停留时间对脱氮效果的影响.结果表明，在电流密度为7.5 mA·cm-2和水力停留时间为3 h的条件下，硝酸盐氮及总氮去除率分别为89.0%和88.6%，N2选择性达到99.3%以上.通过对体系稳定性的考察，发现随反应时间的延长阴极的还原效率逐渐降低，但对阴极极板进行酸洗后用砂纸清理阴极表面可使体系脱氮效能恢复至初始状态.自由基淬灭试验表明，阴极的直接还原作用为体系中硝酸盐的主要还原机制.
- Abstract：The synchronous electro-oxidation and reduction system for denitrification was established on the basis of highly efficient cathode and dimensional stable anode, which can simultaneously reduce nitrate and remove total nitrogen. The treatment of electrogalvanizing pickling wastewater by a continuous flow electrochemical denitrification reactor was conducted. The effects of current density and hydraulic retention time on denitrification were investigated. The results showed that under the current density of 7.5 mA·cm-2 and hydraulic residence time of 3 h, the removal efficiencies of nitrate and total nitrogen were 89.0% and 88.6%, respectively, and the N2 selectivity was higher than 99.3%. The stability of the system was investigated, and it was found that the reduction activity of the cathode decreased with the prolongation of reaction time. However, the denitrification efficiency of the system can be recovered by cleaning the cathode surface successively with dilute acid and sandpaper. The radical quenching experiment showed that the direct cathodic reduction was mainly responsible for nitrate reduction.
