电极间距对CW-MFC处理污泥中Zn和Ni的效果及其产电性能的影响

为有效提高传统人工湿地（CW）处理污泥重金属效能，本文构建了人工湿地微生物燃料电池（CW-MFC）用于污泥中Zn和Ni的去除，并考察了电极间距对Zn和Ni去除效果及其产电性能的影响。结果表明，不同电极间距（12cm、15cm、18cm和20cm）的CW-MFC对Zn的去除率分别为84.68%、64.56%、66.98%和50.23%，对Ni的去除率分别为74.14%、66.09%、64.00%和48.01%。其中，间距为12cm时系统对Zn和Ni去除效果最好，分别较CW提高了64%和26%，此时CW-MFC系统的最高输出电压和最大功率密度分别达到513mV和50.76mW/m³。X射线光电子能谱（XPS）分析显示污泥表层主要的重金属为Zn和Ni，且高价态的Zn和Ni被有效地转化为低价态或者单质金属。在间距为12cm的CW-MFC系统中，植物根系和电极对Zn、Ni的去除贡献最大，此时Zn在植物根系和电极中的富集率分别为23.76% 和30.97%，Ni的富集率分别为14.57%和16.78%。本研究表明CW-MFC对污泥重金属的去除及其产电性能具有较好的效果，并为CW-MFC的优化构建和城市污泥的处置及资源化利用提供了新的思路和借鉴。

Effect of electrode spacing on the removal of Zn and Ni in sludge and its electricity generation performance by CW-MFC

In order to effectively improve the efficiency of traditionally constructed wetlands (CW) for heavy metals treatment in sludge, constructed wetland microbial fuel cells were used for the removal of Zn and Ni in sludge, and the effect of electrode spaces on the Zn and Ni removal and the electricity generation performance were investigated. Results showed that the removal rates of Zn by CW-MFC with different electrode spacings (12cm, 15cm, 18cm and 20cm) were 84.68%, 64.56%, 66.98% and 50.23%, and the removal rates of Ni were 74.14%, 66.09%, 64.00% and 48.01%, respectively. Among them, Zn and Ni had the highest removal rate when the electrode space was 12cm, respectively, which were higher than traditional constructed wetland (CW) for 64% and 26%, respectively. In addition, under the 12cm space, the maximum output voltage and maximum power density of CW-MFC system reached 513mV and 50.76mW/m³, respectively. XPS analysis showed that the main heavy metals on the surface of the sludge were Zn and Ni, and high-valence Zn and Ni were effectively converted into low-valence substances or elemental substances. In CW-MFC system with a spacing of 12cm, the plant roots and electrodes contribute the most to the removal of Zn and Ni. In this case, the enrichment rates of Zn and Ni in the plant roots and electrodes were 23.76%, 30.97%, and 14.57%, 16.78%, respectively. This study shows that CW-MFC has a good effect on the removal of heavy metals from sludge and its power generation performance. Furthermore, it provides new ideas and references for the optimization of CW-MFC and the disposal and resource utilization of urban sludge.