School of Environmental Science and Engineering, Tianjin University, Tianjin, 300350, China; Research Center for Eco-Environmental Science, China Academy of Science, Beijing, 100085, China.
School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China.
J Environ Manage. 2022 Aug 1;315:115203. doi: 10.1016/j.jenvman.2022.115203. Epub 2022 May 4.
In biofilm electrode reactors (BER), good nitrate removal performance can be achieved through cooperation of heterotrophic and hydrogen autotrophic denitrification under low carbon/nitrogen conditions. In this study, we proposed a more multifunctional composite cathode, which combine immobilized anthraquinone-2,6-disulphonic disodium salt (AQDS) with polypyrrole (PPy) by electrochemical polymerization-doping method. The nitrate removal performance in BER with PPy/AQDS composite cathode was obviously improved, the nitrate removal rate (4.96 mg/L·h) was almost 2.0 times higher than the control BER system, and relatively stabled nitrate removal efficiency (≥90.0%) was also achieved even as the COD/N of 2.50. Compared with the bare graphite felt, PPy/AQDS coating cathode showed much better electrocatalytic activities, which was more advantageous for in situ production of H to support hydrogen autotrophic denitrification process. The PPy-bound AQDS could also act as electron intermediaries, which is beneficial to greatly promote indirect electron process between the denitrifiers and nitrate. Moreover, the PPy/AQDS composite layer formed many particles for improving the specific surface area and bio-attachment site for bacterial attachment, which was conducive for the proliferation of microorganisms and denitrification efficiency. The ratio of biofilm and electrode of PPy/AQDS biocathode was 0.32 ± 0.08, which was 2.46 times than bare electrode (0.13 ± 0.06). Furthermore, enrichment of specific denitrifiers and enhancement of denitrifying enzyme activity was obtained using PPy/AQDS treated electrode, the much higher relative abundance of Thauera of PPy/AQDS biocathode was 1.58 times to the application of bare graphite felt.
在生物膜电极反应器（BER）中，通过异养和氢自养反硝化的协同作用，可以在低碳/氮条件下实现良好的硝酸盐去除性能。在这项研究中，我们提出了一种更多功能的复合阴极，它通过电化学聚合掺杂法将固定化蒽醌-2,6-二磺酸钠（AQDS）与聚吡咯（PPy）结合在一起。BER 中使用 PPy/AQDS 复合阴极的硝酸盐去除性能明显提高，硝酸盐去除率（4.96mg/L·h）几乎是对照 BER 系统的 2.0 倍，即使 COD/N 为 2.50，也能达到相对稳定的硝酸盐去除效率（≥90.0%）。与裸石墨毡相比，PPy/AQDS 涂层阴极表现出更好的电催化活性，更有利于原位产生 H 以支持氢自养反硝化过程。结合的 AQDS 还可以作为电子介体，有利于极大地促进反硝化菌与硝酸盐之间的间接电子过程。此外，PPy/AQDS 复合层形成了许多颗粒，提高了比表面积和生物附着位点，有利于微生物的增殖和反硝化效率。PPy/AQDS 生物阴极的生物膜与电极的比例为 0.32±0.08，是裸电极（0.13±0.06）的 2.46 倍。此外，使用 PPy/AQDS 处理的电极获得了特定反硝化菌的富集和反硝化酶活性的增强，PPy/AQDS 生物阴极的 Thauera 相对丰度比裸石墨毡提高了 1.58 倍。
