Abstract:

Aiming at the problem that phosphorus (P) deposited in sediments was re-released by microbial activities, which resulted in the repeated eutrophication of lakes, this paper studied the method of limiting the release of deposited phosphorus to overlying water by Sediment Microbial Fuel Cell (SMFC). A SMFC system was established with the sediment and water from Mei Lake, Zhengzhou University. The voltage, anode electrode potential of SMFC, overlying water temperature and pH were regularly detected. The sediment phosphorus was extracted stepwise by Standard Measurements and Testing (SMT) method. At the beginning and end of the experiment, anodic microbial samples were collected for high throughput gene analysis. The concentration distribution of labile phosphorus with submillimeter resolution in SMFC sediments was visualized using Zr-Oxide DGT for the first time. The results showed that the anode electrode potential of SMFC increased from -100 mV to 230 mV; pH in overlying water increased from 7.15 to 7.46; Loss on Ignition (LOI) of SMFC sediments decreased from 18.31%±0.7% to 13.09%±1.10%, which was lower than that in the control group (14.29%± 2.10%). SMFC significantly promoted the phosphorus mineralization process from the pore water to the sediment, and NaOH-P and HCl-P showed obvious local increases in the vertical direction of the sediment. According to the 2D images of sediment DGT phosphorus, SMFC reduced the concentration of sediment DGT phosphorus by 66% compared with the initial value. Based on Kyoto Encyclopedia of Genes and Genomes (KEGG) database analysis, SMFC significantly increased the abundance of phosphorus-related functional genes. The results showed that SMFC had a significant effect on the distribution of phosphorus in sediments and aqueous phases; the dissolution of solid phase P was alleviated by organic substrate competition between the Fe(III) reduction and solid electrode and anode potential increase, and the conversion of aqueous phase P to sedimentary phase P was finally promoted. SMFC can be used to in-situ stabilize phosphorus in the sediment of eutrophic water. This paper explored the mechanism of phosphorus immobilization by SMFC, and provides novel ideas for the remediation of endogenous phosphorus pollution in water bodies.

Key words: sediment microbial fuel cell (SMFC), diffusive gradients in thin-films, phosphorus, SMT method, KEGG.

摘要：

针对沉积物中沉积磷（P）通过微生物活动再释放，致使湖泊富营养化反复的问题，采集郑州大学眉湖上覆水和沉积物，搭建一个沉积式微生物燃料电池（Sediment Microbial Fuel Cell，SMFC）系统，研究了通过SMFC限制沉积磷向上覆水体释放的方法。实验周期内监测SMFC的电压和阳极电极电位、上覆水温度pH、沉积物磷的Standards Measurements and Testing（SMT）法分级提取；并在实验开始与结束收集阳极微生物样进行微生物群落及基因分析；首次使用氧化锆薄膜扩散梯度技术（Zr-Oxide Diffusive Gradients in Thin-films，Zr-Oxide DGT）可视化了SMFC沉积物中不稳定磷亚毫米分辨率的浓度分布。结果表明：SMFC阳极电极电位从-100 mV升至230 mV；上覆水pH从7.15升至7.46；SMFC沉积物烧失量（Loss on Ignition，LOI）从18.31%±0.7%降至13.09%±1.10%，低于对照组的14.29%±2.10%；SMFC显著促进了孔隙水磷向沉积物磷的矿化过程，在沉积物垂向方向上，NaOH-P和HCl-P出现了明显的区域性增加；根据沉积物DGT磷的二维（2D）图像，SMFC使沉积物DGT磷的浓度最低降至初始值的66%；基于京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes，KEGG）数据库的功能基因分析，SMFC使磷相关功能基因丰度显著增加。证明SMFC对于沉积物磷和水相磷分布有显著影响，通过基质竞争、提高阳极电位等方式减弱固相磷的溶解，促进水相磷向沉积相磷的转化，可用于富营养化水体原位底泥磷稳定化。该文深入研究了SMFC固磷作用机理，为修复水体内源磷污染提供了一种新思路。

关键词: 沉积物微生物燃料电池, 薄膜梯度扩散技术, 磷, 标准测量测试方法（SMT法）, 京都基因与基因组百科全书