A hybrid fuel cell for water purification and simultaneously electricity generation

● A novel hybrid fuel cell (F-HFC) was fabricated. ● Pollutant degradation and synchronous electricity generation occurred in F-HFC. ● BiOCl-NH₄PTA photocatalyst greatly improved electron transfer and charge separation. ● Pollutant could act as substrate directly in ambient conditions without pretreatment. ● The mechanism of the F-HFC was proposed and elucidated. The development of highly efficient energy conversion technologies to extract energy from wastewater is urgently needed, especially in facing of increasing energy and environment burdens. Here, we successfully fabricated a novel hybrid fuel cell with BiOCl-NH₄PTA as photocatalyst. The polyoxometalate (NH₄PTA) act as the acceptor of photoelectrons and could retard the recombination of photogenerated electrons and holes, which lead to superior photocatalytic degradation. By utilizing BiOCl-NH₄PTA as photocatalysts and Pt/C air-cathode, we successfully constructed an electron and mass transfer enhanced photocatalytic hybrid fuel cell with flow-through field (F-HFC). In this novel fuel cell, dyes and biomass could be directly degraded and stable power output could be obtained. About 87 % of dyes could be degraded in 30 min irradiation and nearly 100 % removed within 90 min. The current density could reach up to ~267.1 μA/cm²; with maximum power density (P_max) of ~16.2 μW/cm² with Rhodamine B as organic pollutant in F-HFC. The power densities were 9.0 μW/cm², 12.2 μW/cm², and 13.9 μW/cm² when using methyl orange (MO), glucose and starch as substrates, respectively. This hybrid fuel cell with BiOCl-NH₄PTA composite fulfills the purpose of decontamination of aqueous organic pollutants and synchronous electricity generation. Moreover, the novel design cell with separated photodegradation unit and the electricity generation unit could bring potential practical application in water purification and energy recovery from wastewater.     

填料型微生物燃料电池产电特性的研究

将石墨和碳毡作为阳极填料组装成填料型微生物燃料电池,其启动期在1 d左右,低于平板型微生物燃料电池的启动期.碳毡作为填料时,微生物燃料电池的最大产电功率密度为1 502 mW/m2(37.6 W/m3),优于石墨作为填料的MFC.将碳毡与碳纸烧结一体以提高填料型微生物燃料电池阳极的导电性,与平板型微生物燃料电池相比,其面积内阻从0.071 Ω穖2下降到0.051 Ω穖2,最大电流密度从3 000 mA上升到8 000 mA,最大产电功率密度从1 100 mW/m2(27.5 W/m3)上升到2426 mW/m2(60.7W/m3),阳极电势平均下降100 mV.循环流量影响填料型微生物燃料电池的产电能力,当流量低于1 mL/min时,其产电功率密度随流速降低而下降.填料型微生物燃料电池在外电阻为600 Ω下长期稳定运行30 d以上,其库仑效率约为10.6%.     

Bioelectricity generation from three ornamental plants: Chlorophytum comosum,Chasmanthe floribunda and Papyrus diffusus

In the present study, bioelectricity generation using a living plant in soil was achieved by converting solar energy into electricity on the principles of plant photosynthesis. The plants Chlorophytum comosum, Chasmanthe floribunda and Papyrus diffuses were used in microbial fuel cells (MFCs) and produced, respectively, a maximum current of 25, 31 and 19 mA/m², without the use of any nutrient or membrane. In this study, the importance of light was demonstrated by the high current values generated during daytime, and the microorganisms at the anode-rhizosphere interface were examined.     

Oxidative destabilization of dissolved organics and E. coli in domestic wastewater through immobilized cell reactor system

Domestic wastewater contains a considerable amount of pathogenic organisms besides non-biodegradable organics. The conventional technologies followed for the treatment of domestic wastewater are less efficient in removing pathogenic organisms despite substantial removal of dissolved organics. The focal theme of the present investigation was to use a chemo-autotrophic activated carbon oxidation (CAACO) system, an immobilized cell reactor using chemoautotrophs (Bacillus sp.) for the treatment of domestic wastewater. The oxidation of organics and Escherichia coli in wastewater is controlled by the parameters space time, O(2)/COD, bed height and cod loading. The scheme comprised of anaerobic treatment, sand filtration and CAACO treatment removed BOD. COD, Total organic carbon (TOC), dissolved protein, total Kjeldhal nitrogen (TKN) and bacterial count (most probable number (MPN)) by 81%, 92%, 84%, 94%, 93% and 99.9997%, respectively. The low concentration of E. coli in the CAACO-treated wastewater was completely eliminated through UV irradiation in 3 min at 254 nm.     

Endocrine Disruptors in Mediterranean top marine predators

- DOI: http://dx.doi.org/10.1065/espr2006.01.018 Background, Aims and Scope Man-made Endocrine Disruptors (EDs) range across all continents and oceans. Some geographic areas are potentially more threatened than others: one of these is the Mediterranean Sea. Levels of some xenobiotics are much higher here than in other seas and oceans. In this paper we review the final results of a project in which the hypothesis that Mediterranean top predator species (such as large pelagic fish and marine mammals) are potentially at risk due to EDs was investigated. Methods In a four-year survey on the Mediterranean population of swordfish (Xiphias gladius), the potential toxicological effects of organochlorine compounds (OCs) on specimens of swordfish and tuna fish (Thunnus thynnus thynnus), caught in the spawning seasons from 1999 to 2002 in the Straits of Messina, Sicily (Italy), were investigated using vitellogenin (Vtg), Zona radiata proteins (Zrp), and cytochrome P4501A (CYP1A) activities (EROD, BPMO). Tissues (skin and blubber) were obtained from Stenella coeruleoalba, Tursiops truncatus, Delphinus delphis and Balaenoptera physalus from the western Ligurian Sea, between Corsica and the French-Italian coast, and Ionic Sea using biopsy darts launched with a crossbow. Benzo(á)pyrene monoxigenase (BPMO) activity was mesured in biopsies and cholrinated hydrocarbon levels were detected. Results and Discussion We illustrate the need to develop and apply sensitive methodological tools, such as biomarkers (Vitellogenin, Zona Radiata proteins and CYP1A activities) for evaluation of toxicological risk in Xiphias gladius and Thunnus thynnus thynnus), and nondestructive biomarkers (CYP1A activities and fibroblast cell culture in skin biopsy), for the hazard assessment of threatened marine mammals species (Stenella coeruleoalba, Tursiops truncatus, Delphinus delphis and Balaenoptera physalus) exposed to EDs. Conclusion The present research shows that: a) Vtg and Zrp can be used as diagnostic tools for fish stocks hazard assessment in the Mediterranean Sea; b) that CYP1A1 (BPMO) induction in cetaceans skin biopsy may be an early sign of exposure to EDs such as OCs and a potential alert for transgenerational effects. Recommendation and Outlook This research represents a warning signal of the potential reproductive alterations in marine top predators and suggest the need for continuous monitoring to avoid reductions in population and biodiversity in the Mediterranean Sea.     

用盐桥支撑双分子层脂膜模拟研究锌离子跨细胞膜输运

采用盐桥支撑技术制备镶嵌胆固醇的双分子层卵磷脂(脑磷脂)膜,用以模拟细胞膜.用正辛烷做溶剂,对不同卵磷脂(脑磷脂)与胆固醇配比进行制膜,膜的稳定性均超过100h.实验发现,纯脂质体不能输运重金属离子,胆固醇能输运重金属离子.胆固醇与重金属离子之间存在吸附作用,无化学反应.采用电化学工作站对双分子层脂膜的稳定性、离子通透性、双层膜中胆固醇对离子通透性的影响等进行了研究,并利用实验制备的双分子层脂膜模拟研究锌离子跨细胞膜的输运过程,建立了锌离子跨细胞膜的吸附-扩散模型,该模型计算值与实验值基本吻合.     

铁氰化钾对双室微生物燃料电池曝气阴极性能的改善

为研究铁氰化钾对双室微生物燃料电池(MFC)阴极性能的改善效果,以碳毡和碳棒作为复合电极材料,乙酸钠为阳极电子供体,分别以氧气、铁氰化钾和氧气交替作为阴极电子受体.通过测定使用铁氰化钾作阴极电极液之前和之后的曝气阴极MFC的功率密度及极化曲线,比较曝气阴极MFC的内阻、开路电压(OCV)和最大输出功率的变化情况.实验结果表明,当以铁氰化钾作为MFC阴极电子受体时,MFC的内阻、开路电压和最大输出功率分别为24.2 Ω、744.2 mV和33.7 W/m3.曝气阴极MFC在采用铁氰化钾作电极液对阴极性能进行改善之前和改善之后的内阻由77.2 Ω降低到40.1Ω,OCV和最大输出功率分别由517.9 mV和2.1 W/m3提高到558.2 mV和4.4 W/m3.研究表明,铁氰化钾本身不仅具有优良的接受电子的能力,而且对电极材料(碳毡和碳棒)的电化学性能具有明显的改善作用,使得使用铁氰化钾之后的曝气阴极MFC的产电性能有了明显且持久性的提高.     

青枯菌不同色谱峰组分的细胞表面特性

将高效离子交换色谱应用于植物重要致病菌——青枯菌的分离分析.青枯菌纯培养物经过色谱分离得到3个特征峰,收集3个色谱峰组分进行形态观察和生理生化鉴定,结果表明3个组分均属于青枯菌生化Ⅲ型;进一步分析发现,3个色谱峰组分在质粒DNA、细胞表面鞭毛菌毛蛋白含量和全细胞脂多糖成分方面无明显差异,但细胞表面黏附的胞外酸性多糖EPSⅠ含量差异显著;3个色谱峰青枯菌细胞表面疏水性的测定结果也证实了EPSⅠ是造成不同青枯菌细胞色谱行为差异的主要原因.高效离子交换色谱为细菌活细胞的研究提供了一种新方法.图4表2参15     

悬沙对小球藻生长的影响

在实验生态条件下研究了不同浓度和粒径大小的悬沙对小球藻(Chlorella sp.)生长的影响.结果发现:在泥沙与小球藻直接混合培养体系中,小球藻的种群增长可用Logistic增长模型拟合,拟合后的生长参数表明,随着悬沙浓度的增加,小球藻的环境负载能力a和种群瞬时增长率K显著减小,但到达拐点时间Tp的变化趋势在不同悬沙粒径组中存在差异.结果对于利用泥沙条件抑制水华爆发有着重要的意义.     

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。