摘要
传统单个PbO2阳极用于污染物去除存在降解效率较差、能耗高的问题,本文构建了PbO2/Fe双阳极体系,通过耦合电氧化技术和电絮凝技术实现对焦化废水同步除碳脱氮.研究发现,双阳极体系下6 h电解使得化学需氧量(COD)和总氮(TN)去除率分别达到50.3%±6.2%和34.9%±4.2%,高于单PbO2阳极体系(21.9%±3.4%和21.1%±5.3%)和单Fe阳极体系(11.0%±1.2%和12.1%±3.1%).COD和TN去除速度与施加在两个阳极上的电流大小直接相关.采用焦化废水中主要污染物如苯酚、硫氰酸盐、氨氮进行配水实验时发现,Fe阳极加入不仅起到了电絮凝作用,还可以促进氧化反应的发生,提高了反应速度.从体系中氯离子、pH变化情况及电子自旋共振光谱结果可推测,Fe阳极释放出来的Fe(Ⅱ)与PbO2阳极氧化氯离子产生的ClO-发生类Fenton反应,生成强氧化性物质作用于污染物氧化降解.
Traditional electrochemical method using the single PbO2 anode for wastewater treatment suffers the problems including insufficient degradation of pollutants and high energy consumption. To address them, we herein reported a PbO2/Fe dual-anode system by integrating electrochemical oxidation and electrocoagulation for simultaneous carbon and nitrogen removal from coking wastewater. The 6-hour operation of the dual anode system enabled chemical oxygen demand(COD) and total nitrogen(TN) removal efficiencies of 50.3%±6.2% and 34.9%±4.2%, respectively, larger than 21.9%±3. 4% and 21.1%±5.3% obtained from the single PbO2 system, and 11.0%±1.2% and 12.1%±3. 1% obtained from the single Fe system. The degradation rates of COD and TN were found to be closely related to the currents applied to the anodes. Testing of the synthetic water containing phenol, thiocyanate, and ammonium revealed that the Fe anode not only contributed to pollutant coagulation but also accounted for pollutant oxidation, which accelerated the overall efficiencies. Based on the results of the variations in the concentrations of Cl- and pH values, and the difference in the electron spin resonance signals, it was proposed that Fe(Ⅱ) released from the Fe anode could react with ClO- generated from the PbO2 anode, and produce oxidative species in a Fenton-like reaction that degrades pollutants.
作者
李勇东
吴迪
郑文笑
严樟
冯春华
韦朝海
LI Yongdong;WU Di;ZHENG Wenxiao;YAN Zhang;FENG Chunhua;WEI Chaohai(School of Environment and Energy,South China University of Technology,Guangzhou,510006,China;The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Cluster,Ministry of Education,Guangzhou,510006,China)
出处
《环境化学》
CAS
CSCD
北大核心
2020年第6期1650-1659,共10页
Environmental Chemistry
基金
国家自然科学基金(21876052)
广州市科技计划项目(201904010293)资助
