以不锈钢筒作为阴极、碳毡作为阳极,阴阳极间利用无纺布作为隔膜构建单室生物电解池,以氨作为唯一电子供体,接入混合菌群,通过恒定不同的阳极电势,考察不同初始浓度氨氮在生物电解池内的氧化与产物的生成情况.结果表明,恒定阳极电势0.2 ...以不锈钢筒作为阴极、碳毡作为阳极,阴阳极间利用无纺布作为隔膜构建单室生物电解池,以氨作为唯一电子供体,接入混合菌群,通过恒定不同的阳极电势,考察不同初始浓度氨氮在生物电解池内的氧化与产物的生成情况.结果表明,恒定阳极电势0.2 V(vs Ag/Ag Cl)时,经过5 d的运行,初始氨氮浓度200 mg/L、400 mg/L的氨氮去除率分别为30%、35%,氮气分别积累16.1 m L、17.18 m L,甲烷分别积累1.18 m L、1.46 m L;恒定阳极电势0.6 V(vs Ag/Ag Cl)时,初始氨氮浓度200 mg/L、400 mg/L,氨氮去除率分别为32.4%、36.6%,分别积累氮气16.48 m L、17.42 m L,积累甲烷1.3m L、1.52 m L,未检测到硝态氮和亚硝态氮.循环伏安扫描分析发现,阳极具有明显的氧化还原峰,且不同的阳极恒定电势,导致其氧化还原峰出现偏移.通过电镜扫描,发现阳极微生物细胞表面具有明显的褶皱形状,高通量分析显示阳极微生物中Geobacter占24.11%,是优势菌群,在阳极氨氧化过程中起到关键作用.同时发现系统中还存在氢营养型产甲烷菌Synergistes(3.8%)以及梭菌Clo stridium(3.8%)和Gordonia(1.85%)等功能微生物.本文研究表明,在生物电解池内,微生物能够以氨氮作为电子供体,通过氨氧化脱氮,并产生氢气和甲烷.展开更多
Cathodic reduction of CO_2 and anodic oxidation of organic matters are crucial to methaneproducing microbial electrolysis cell(MEC) applied in anaerobic digestion of waste activated sludge. However, cathodic CO_2 redu...Cathodic reduction of CO_2 and anodic oxidation of organic matters are crucial to methaneproducing microbial electrolysis cell(MEC) applied in anaerobic digestion of waste activated sludge. However, cathodic CO_2 reduction is usually restrained by slow metabolism rates of H_2-utilizing methanogens and low electron-capturing capacity of CO_2, which consequently slows down the anodic oxidation that participates to sludge disintegration. Herein, a strategy with adding nitrate as electron acceptor to foster electronic transfer between the anode and cathode was proposed to improve anodic oxidation. Results showed that the average efficiency of anodic oxidation in the nitrate-added MEC increased by 55.9%. Accordingly,volatile suspended solid removal efficiency in the nitrate-added MEC was 21.9% higher than that of control MEC. Although the initial cumulative methane production in the nitrateadded MEC was lower than that of control MEC, the cumulative methane production in 24 days was 8.9% higher. Fourier transform infrared spectroscopy analysis indicated that anodic oxidation of MEC with nitrate accelerated the disintegration of sludge flocs and cell walls. Calculation on current signal further revealed that anodic oxidation driven by cathodic nitrate reduction was the main mechanism responsible for the improved sludge digestion.展开更多
文摘以不锈钢筒作为阴极、碳毡作为阳极,阴阳极间利用无纺布作为隔膜构建单室生物电解池,以氨作为唯一电子供体,接入混合菌群,通过恒定不同的阳极电势,考察不同初始浓度氨氮在生物电解池内的氧化与产物的生成情况.结果表明,恒定阳极电势0.2 V(vs Ag/Ag Cl)时,经过5 d的运行,初始氨氮浓度200 mg/L、400 mg/L的氨氮去除率分别为30%、35%,氮气分别积累16.1 m L、17.18 m L,甲烷分别积累1.18 m L、1.46 m L;恒定阳极电势0.6 V(vs Ag/Ag Cl)时,初始氨氮浓度200 mg/L、400 mg/L,氨氮去除率分别为32.4%、36.6%,分别积累氮气16.48 m L、17.42 m L,积累甲烷1.3m L、1.52 m L,未检测到硝态氮和亚硝态氮.循环伏安扫描分析发现,阳极具有明显的氧化还原峰,且不同的阳极恒定电势,导致其氧化还原峰出现偏移.通过电镜扫描,发现阳极微生物细胞表面具有明显的褶皱形状,高通量分析显示阳极微生物中Geobacter占24.11%,是优势菌群,在阳极氨氧化过程中起到关键作用.同时发现系统中还存在氢营养型产甲烷菌Synergistes(3.8%)以及梭菌Clo stridium(3.8%)和Gordonia(1.85%)等功能微生物.本文研究表明,在生物电解池内,微生物能够以氨氮作为电子供体,通过氨氧化脱氮,并产生氢气和甲烷.
基金supported by the National Natural Scientific Foundation of China(No.51578105)
文摘Cathodic reduction of CO_2 and anodic oxidation of organic matters are crucial to methaneproducing microbial electrolysis cell(MEC) applied in anaerobic digestion of waste activated sludge. However, cathodic CO_2 reduction is usually restrained by slow metabolism rates of H_2-utilizing methanogens and low electron-capturing capacity of CO_2, which consequently slows down the anodic oxidation that participates to sludge disintegration. Herein, a strategy with adding nitrate as electron acceptor to foster electronic transfer between the anode and cathode was proposed to improve anodic oxidation. Results showed that the average efficiency of anodic oxidation in the nitrate-added MEC increased by 55.9%. Accordingly,volatile suspended solid removal efficiency in the nitrate-added MEC was 21.9% higher than that of control MEC. Although the initial cumulative methane production in the nitrateadded MEC was lower than that of control MEC, the cumulative methane production in 24 days was 8.9% higher. Fourier transform infrared spectroscopy analysis indicated that anodic oxidation of MEC with nitrate accelerated the disintegration of sludge flocs and cell walls. Calculation on current signal further revealed that anodic oxidation driven by cathodic nitrate reduction was the main mechanism responsible for the improved sludge digestion.
