微生物燃料电池处理含S2-/NH4+废水的研究

以除硫硝化微生物燃料电池(Microbial Fuel Cell,MFC)处理含S~(2-)/NH_4~+的模拟无机废水,研究了不同进水S~(2-)浓度下MFC的产电性能、污染物去除效果和阳极室硫累积情况.结果表明,除硫硝化MFC可实现同步阳极除硫和阴极硝化,并通过非生物电化学作用和生物电化学作用共同产电.进水S~(2-)浓度为(60.8±2.9)、(131.7±2.4)、(161.7±4.5)和(198.1±3.1)mg·L~(-1)时,最佳阳极碳刷清洗周期分别为3、3、3、4个换水周期,前3个进水浓度下的换水周期可分别缩短为6、8和8 h.MFC阴极硝化完全,不受进水S~(2-)浓度影响,但氧从阴极向阳极的渗漏导致阳极库仑效率较低(40%).适当增加进水S~(2-)浓度可增强MFC的产电性能并提高S~(2-)去除负荷和颗粒硫累积比.除硫硝化MFC适宜的进水S~(2-)浓度为(161.7±4.5)mg·L~(-1),相应的最大功率密度为5.77 W·m~(-3),周期产电量为(141.0±5.2)C,S~(2-)去除负荷为(0.31±0.00)g·L~(-1)·d~(-1),颗粒硫累积比达58%.阳极碳纤维丝上沉积有粒径约100 nm的颗粒硫.阳极悬浮物与沉积物相比,悬浮物中S0含量比例较高,而S6+含量比例较低.

Treatment of wastewater containing sulfide/ammonium in a microbial fuel cell

A sulfide removal and nitrification microbial fuel cell (MFC) was constructed to treat synthetic inorganic wastewater containing sulfide and ammonium. The electricity generation characteristics, pollutants removal, and sulfur deposition were investigated at different feeding concentrations of sulfide. Simultaneous sulfide removal and nitrification, coupled with power recovery through both abiotic and biotic electrochemical processes, were obtained in this sulfide removal and nitrification MFC. When the feeding concentrations of sulfide were set at (60.8±2.9), (131.7±2.4), (161.7±4.5) and (198.1±3.1) mg·L^-1, the optimal washing intervals of anodic carbon brush were 3, 3, 3, and 4 batch cycles, respectively, and the duration of batch cycles could be shortened to 6, 8, and 8 h for the former 3 concentration conditions. Complete nitrification was achieved in the cathode chamber of MFC at the applied sulfide feeding concentrations, but low columbic efficiency (below 40%) was found due to oxygen diffusing from the cathode to the anode chamber. Moderately increasing the feeding concentration of sulfide enhanced charge recovery along with the increase in sulfide removal and accumulation of granular sulfur. The suitable feeding concentration of sulfide was deemed as (161.7±4.5) mg·L^-1, achieving a maximum power density of 5.77 W·m^-3, a batch charge recovery of (141.0±5.2) C, a sulfide removal loading of (0.31±0.00) g·L^-1·d^-1, and an accumulation percent for granular sulfur of 58%. The granular sulfur was approximate 100 nm in diameter deposited on the anodic carbon fiber. Compared to anodic deposits, S⁰ in the anodic suspensions was higher than S⁶⁺.