HgCl2对斜生栅藻（Scenedesmus obliquus）生理生化特性的影响(Effects of HgCl2 on Physiological and Biochemical Characteristics of Scenedesmus obliquus)

为探讨汞对藻类的毒性效应,以斜生栅藻(Scenedesmus obliquus)为实验材料,检测了HgCl2对藻细胞数目、光合色素含量、超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量等生化指标的影响.结果表明,各暴露组(0.2～1.5mg·L-1)HgCl2对斜生栅藻的生长均有抑制作用,随HgCl2暴露浓度的增大,藻细胞密度逐渐降低,HgCl2对斜生栅藻的48、72、96hEC50值分别为1.194、1.113、0.986mg·L-1.随着HgCl2暴露浓度的升高(0.01～1.5mg·L-1),叶绿素a、b及类胡萝卜素等光合色素含量均呈逐渐降低趋势;SOD活性表现为先激活后抑制;MDA含量则显著增加(p<0.05,p<0.01).     

Scaling up a novel denitrifying microbial fuel cell with an oxic-anoxic two stage biocathode

A scaled up microbial fuel cell （MFC） of a 50 L volume was set up with an oxic-anoxic two-stage biocathode and activated semicoke packed electrodes to achieve simultaneous power generation and nitrogen and organic matter removals. An average maximum power density of 43.1 W·m^-3 was obtained in batch operating mode. By adjusting the two extemal resistances, the denitrification in the A-MFC and power production in the O-MFC could be enhanced. In continuous mode, when the hydraulic retention times were set at 6 h, 8 h and 12 h, the removal efficiencies of COD, NHf-N and total nitrogen （TN） were higher than 95%, 97%, and 84%, respectively. Meanwhile the removal loads for COD, NH4^＋-N and TN were10, 0.37 and 0.4 kg·（m^3·d）^-1, respectively.     

Using crosslinked polyvinyl alcohol polymer membrane as a separator in the microbial fuel cell

Separator between anode and cathode is an essential part of the microbial fuel cell （MFC） and its property could significantly influence the system perfor- mance. In this study we used polyvinyl alcohol （PVA） polymer membrane crosslinked with sulfosuccinic acid （SSA） as a new separator for the MFC. The highest power density of 7594-4 mW-m-2 was obtained when MFC using the PVA membrane crosslinked with 15% of SSA due to its desirable proton conductivity （5.16 x 10-2 S.cml）. The power density significantly increased to 11064- 30 mW.m-2 with a separator-electrode-assembly config- uration, which was comparable with glass fiber （11704- 46 mW.m-2）. The coulombic efficiencies of the MFCs with crosslinked PVA membranes ranged from 36.3% to 45.7% at a fix external resistance of lO00f2. The crosslinked PVA membrane could be a promising alter- native to separator materials for constructing practical MFC system.     

Microbial electrolysis cells with biocathodes and driven by microbial fuel cells for simultaneous enhanced Co(II) and Cu(II) removal

Cobalt and copper recovery from aqueous Co(II) and Cu(II) is one critical step for cobalt and copper wastewaters treatment. Previous tests have primarily examined Cu(II) and Co(II) removal in microbial electrolysis cells (MECs) with abiotic cathodes and driven by microbial fuel cell (MFCs). However, Cu(II) and Co(II) removal rates were still slow. Here we report MECs with biocathodes and driven by MFCs where enhanced removal rates of 6.0±0.2 mg?L⁻¹?h⁻¹ for Cu(II) at an initial concentration of 50 mg?L⁻¹ and 5.3±0.4 mg?L⁻¹ h⁻¹ for Co(II) at an initial 40 mg?L⁻¹ were achieved, 1.7 times and 3.3 times as high as those in MECs with abiotic cathodes and driven by MFCs. Species of Cu(II) was reduced to pure copper on the cathodes of MFCs whereas Co(II) was removed associated with microorganisms on the cathodes of the connected MECs. Higher Cu(II) concentrations and smaller working volumes in the cathode chambers of MFCs further improved removal rates of Cu(II) (115.7 mg?L⁻¹?h⁻¹) and Co(II) (6.4 mg?L⁻¹?h⁻¹) with concomitantly achieving hydrogen generation (0.05±0.00 mol?mol⁻¹ COD). Phylogenetic analysis on the biocathodes indicates Proteobacteria dominantly accounted for 67.9% of the total reads, followed by Firmicutes (14.0%), Bacteroidetes (6.1%), Tenericutes (2.5%), Lentisphaerae (1.4%), and Synergistetes (1.0%). This study provides a beneficial attempt to achieve simultaneous enhanced Cu(II) and Co(II) removal, and efficient Cu(II) and Co(II) wastewaters treatment without any external energy consumption.     

外阻对污泥微生物燃料电池产电以及有机物降解的影响

重点考察了不同外阻（10、150和1 000Ω）对污泥微生物燃料电池（sludge microbial fuel cell,SMFC）产电性能及有机物去除速率的影响。结果表明,外阻对电池产电和有机物降解有显著影响,低电阻有利于电流产生及有机物消耗。当外阻为10Ω时,输出电流最高（4.2 mA）,且污泥溶解性化学需氧量（SCOD）去除速率最快（53 mg.d-1）。DGGE图谱显示,不同外阻导致阳极微生物菌落结构有明显差异;CV扫描发现外阻对生物膜氧化还原能力有显著影响,低电阻下运行的阳极生物膜氧化还原活性较强。本研究为理解外阻与阳极生物膜间的关系提供一条有益线索,也为MFC性能提高提供一条可操作性的途径。     

DOW CORNING 1-2577 Conformal Coating as an efficient diffusion material for cathode in the microbial fuel cell

In this study, DOW CORNING 1-2577 Conformal Coating was proposed for the cathode diffusion layer of the microbial fuel cell (MFC). In MFCs, stainless steel mesh cathodes using DOW CORNING 1-2577 Conformal Coating/carbon as the diffusion layer and two poly (dimethylsiloxane) (PDMS)/carbon diffusion layers and carbon cloth cathode with four poly (tetrafluoroethylene) (PTFE) diffusion layers were constructed for comparison. Under the same operational condition, the MFCs with the DOW CORNING 1-2577 Conformal Coating/carbon diffusion layer produced the maximum power density of 1585±52 mW·m^-2, compared with those using poly (tetrafluoroethylene) (PTFE) diffusion layers (1421±45 mW·m^-2) and poly (dimethylsiloxane) (PDMS)/carbon diffusion layers (1353±49 mW·m^-2). The DOW CORNING 1-2577 Conformal Coating could be an alternative for the diffusion layer construction in the MFC due to its remarkable performance and much simple construction procedure.