Key Laboratory for Technology in Rural Water Management of Zhejiang Province, Zhejiang University of Water Resources and Electric Power, Hangzhou, 310018, China; College of Water Conservancy and Environmental Engineering, Zhejiang University of Water Resources and Electric Power, Hangzhou, 310018, China.
College of Water Conservancy and Environmental Engineering, Zhejiang University of Water Resources and Electric Power, Hangzhou, 310018, China.
Chemosphere. 2022 Aug;301:134744. doi: 10.1016/j.chemosphere.2022.134744. Epub 2022 Apr 27.
A biochar electrode based biofilm reactor was developed for advanced removal of nitrate from agricultural runoff. The corn-straw (Zea mays L.) biochar formed at 500 °C has an adsorption capacity of NO-N up to 2.659 mg g. After 45-day start-up phase, the removal efficiency of nitrate reached 93.4% when impressed current was 20 mA, hydraulic retention time was 12 h and chemical oxygen demand/total nitrogen (C/N) ratio was 0.56 without additional carbon source. In comparison, neither electrochemical reduction alone nor microbial denitrification alone could obtain the ideal nitrate removal efficiency. The results implied that bio-electrochemical reduction was the main way of nitrate removal in the biofilm electrode reactor (BER). The denitrification efficiency of 88.9% could still be obtained when C/N = 0. It is because biochar can significantly promote the utilization efficiency of cathode electrons by microorganisms. Thus, biochar is a promising electrode material, which provides a new idea for the optimization of BER.
基于生物炭电极的生物膜反应器用于农业径流中硝酸盐的深度去除。在 500°C 下形成的玉米秸秆（Zea mays L.）生物炭对 NO-N 的吸附容量高达 2.659mg/g。经过 45 天的启动阶段，当施加电流为 20 mA、水力停留时间为 12 小时、化学需氧量/总氮（C/N）比为 0.56 时，无需额外添加碳源，硝酸盐的去除效率达到 93.4%。相比之下，单独的电化学还原或微生物反硝化都无法获得理想的硝酸盐去除效率。结果表明，生物电化学还原是生物膜电极反应器（BER）中硝酸盐去除的主要途径。当 C/N=0 时，仍可获得 88.9%的反硝化效率。这是因为生物炭可以显著提高微生物对阴极电子的利用效率。因此，生物炭是一种很有前途的电极材料，为 BER 的优化提供了新的思路。
