电辅助膜生物反应器体系中Co纳米催化膜处理焦化废水研究

为探究电辅助膜生物反应器（electrical membrane bioreactor，EMBR）处理难降解有机废水的效果、产电性能及抗膜污染性能，以金属有机骨架化合物（metal-organic frameworks，MOFs）为前驱体，通过碳化制备具有高催化氧还原（oxygen reduction reaction，ORR）活性的负载Co纳米颗粒的氮掺杂碳催化剂（Co-NPs），以碳纤维布作为基体组装Co-NPs/PVDF碳纤维基催化膜，并构建催化膜耦合EMBR体系处理实际焦化废水.考察碳化温度、Co/N协同作用、N掺杂含量及形态对ORR活性的影响，探究了催化膜在EMBR体系中处理实际焦化废水的污染物去除效率、抗污染特性和产能效果.结果表明:①Co-NPs的ORR反应为4电子转移还原途径，还原产物为水.②Co-NPs/PVDF碳纤维基催化膜在微电场下保持稳定的高膜通量.催化膜污染在运行初期符合膜孔堵塞模型，后期表现为滤饼层污染模型控制，膜污染以滤饼层污染为主.微电场可以降低滤饼层比阻，能有效解决膜污染问题.③EMBR体系处理实际焦化废水，COD、TN、NH₄+-N和挥发酚的去除率分别为97.2%、43.8%、82.9%和99.8%.④系统最大产电功率密度为823.8 mW/m3，库仑效率为8.3%.研究显示，以MOFs为前驱体制备的Co-NPs纳米催化剂，以碳纤维布作为基体制备Co-NPs/PVDF碳纤维基催化膜，耦合EMBR体系在焦化废水处理过程中表现出了高效的污染物降解效率、能源转化效率，并且微电场环境可达到抗膜污染效果. 

Coking Wastewater Treatment by Co Nanocatalytic Membrane in Electrical Membrane Bioreactor System

In order to improve the electricity generation performance and membrane anti-fouling properties, the Co-NPs/PVDF carbon fiber catalytic membrane was prepared by using metal-organic frameworks (MOFs) as precursor to prepare nitrogen-doped carbon with supported Co nanocatalysts (Co-NPs) for high oxygen reduction reaction (ORR) catalytic activity through high-temperature carbonization, and carbon fiber cloth as the matrix. The catalytic membrane coupled EMBR system was constructed to treat the actual coking wastewater. The effects of carbonization temperature, Co/N synergistic action, N-doped content and speciation on ORR activity were investigated. The pollutant removal efficiency, anti-fouling characteristics and efficiency of electricity production in EMBR treatment of coking wastewater were explored. The results showed that the ORR reaction of Co-NPs was 4 electron transfer reduction pathway and the reduced product was water. The Co-NPs/PVDF carbon fiber catalytic membrane can maintain a high stable membrane flux under the microelectric field. In the early stage, the catalytic fouling conformed to the membrane hole plugging model. While, in the later stage, the membrane fouling was controlled by the filter cake fouling model and the membrane fouling was mainly the contamination of the filter cake layer. The micro-electric field can reduce the specific resistance of the membrane filter cake layer and effectively solve the problem of membrane fouling. The EMBR system treated the actual coking wastewater and the degradation rates of COD, TN, NH₄+-N and volatile phenol were 97.2%, 43.8%, 82.9% and 99.8%, respectively. The maximum electrical power density of the EMBR was 823.8 mW/m3 and the coulomb efficiency was about 8.3%. The results indicated that the Co-NPs/PVDF carbon fiber catalytic membrane that was prepared by using metal-organic frameworks (MOFs) as precursor to prepare Co-NPs and carbon fiber cloth as the matrix and coupled EMBR system had shown high pollutant degradation efficiency and energy conversion efficiency in the coking wastewater treatment, and the micro-electric field can achieve the effect of membrane anti-fouling.