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。     

Effects of oxidizing environment on digestate humification and identification of substances governing the dissolved organic matter (DOM) transformation process

• Liquid digestate humification was investigated under different oxidizing environment. • Tryptophan-like substances dominated the transformation of the liquid digestate DOM. • The humification sequence of the liquid digestate DOM was identified. • UV₃₂₅ was first identified as a pre-humus intermediate during humification reaction. The formation of humic-like acids (HLAs) is an essential process for converting liquid digestate into organic soil amendments to enhance agricultural sustainability. The aim of this study was to investigate the impact of oxygen and/or MnO₂ on the production of HLAs. Herein, abiotic humification performance of the digestate dissolved organic matter (DOM) is investigated with fluxes of air and N₂ in the absence and presence of MnO₂. Our results demonstrated that the fate of digestate DOM greatly depends on the oxidizing environment, the MnO₂ enhanced nitrogen involved in the formation of HLAs. The synergistic effects of MnO₂ and oxygen effectively improved the production of HLAs, and the corresponding component evolution was analyzed using spectroscopic evidence. The two-dimensional correlation spectroscopy results demonstrated that the reaction sequence of digestate DOM followed the order of protein-like substances, substances with an absorbance at 325 nm, substances with UV absorbance at 254 nm and HLAs. Additionally, excitation emission matrix fluorescence combined with parallel factor analysis (EEM-PARAFAC) showed that tryptophan-like C3 was more prone to transformation than tyrosine-like C2 and was responsible for the humification process. The substance with an absorbance at 325 nm was a reaction intermediate in the transformation process of protein-like substances to HLAs. The above findings can be used to promote the production of liquid fertilizer associated with carbon sequestration as well as the sustainable development of biogas production.     

Impacts of methanol fuel on vehicular emissions: A review

● Methanol effectively reduces CO, HC, CO₂, PM, and PN emissions of gasoline vehicles. ● Elemental composition of methanol directly affects the reduction of emissions. ● Several physicochemical properties of methanol help reduce vehicle emissions. The transport sector is a significant energy consumer and a major contributor to urban air pollution. At present, the substitution of cleaner fuel is one feasible way to deal with the growing energy demand and environmental pollution. Methanol has been recognized as a good alternative to gasoline due to its good combustion performance. In the past decades, many studies have investigated exhaust emissions using methanol-gasoline blends. However, the conclusions derived from different studies vary significantly, and the explanations for the effects of methanol blending on exhaust emissions are also inconsistent. This review summarizes the characteristics of CO, HC, NO_x, CO₂, and particulate emissions from methanol-gasoline blended fuels and pure methanol fuel. CO, HC, CO₂, particle mass (PM), and particle number (PN) emissions decrease when methanol-blended fuel is used in place of gasoline fuel. NO_x emission either decreases or increases depending on the test conditions, i.e., methanol content. Furthermore, this review synthesizes the mechanisms by which methanol-blended fuel influences pollutant emissions. This review provides insight into the pollutant emissions from methanol-blended fuel, which will aid policymakers in making energy strategy decisions that take urban air pollution, climate change, and energy security into account.     

燃气汽车的经济外部性分析及发展策略研究

从经济外部性的角度出发，对燃气汽车和燃油汽车进行了比较分析，论主下了燃油汽车具有负的外部性以及燃气汽车具有正的外部性。为解决外部性问题、促进燃气汽车发展，政府干预是必要的。     

Nuclear Wastes in the Arctic Ocean. the Consequences of Past Dumping and Opportunities for Future Prevention

The view is expressed that the assessment of disposal of nuclear waste in the ocean (specifically the Arctic and Kara Seas) is critical to understanding Arctic pollution. Much needs to be done in deciding what we should do, even though many wastes are long-standing and persistent. in 1993, disclosures about Russian dumping of submarine nuclear reactors, nuclear fuel, and other radioactive wastes into the Arctic Ocean brought this region and its problems into the world spotlight and raised public concerns about the resulting health and environmental risks. As a result of this concern, the Congressional Office of Technology Assessment published a 1995 study, Nuclear Wastes in the Arctic (US Congress Office of Technology Assessment, 1995). This paper summarises and updates that study.     

Strategy of Biological Reclamation of Chemically Polluted Ecosystems

The strategy of biological reclamation of ecosystems in the zones of chemical pollution with asymmetrical dimethylhydrazine (ADMH), a highly toxic propellant, is proposed. The strategy is based on the results of comprehensive studies on trends in the interactions of soils, plants, and accompanying microorganisms with ADMH at rocket stage drop sites and in specially established test areas, under natural and controlled conditions.__________Translated from Ekologiya, No. 3, 2005, pp. 193–200.Original Russian Text Copyright © 2005 by Ermakov, Panova, Stepanova.     

Directing technical change from fossil-fuel to renewable energy innovation: An application using firm-level patent data

In this paper we provide an analysis of directed technical change in the sector of electricity generation. We rely on patent data in fossil-fuel (FF) and renewable energy (REN) technologies for 5471 European firms over the 1978–2006 period. The novelty of our approach is in the focus on firm׳s heterogeneity in driving technological change. We make a distinction between small specialized firms, which innovate in only one type of technology, and large mixed firms, which innovate in both technologies, to analyse how REN patents can replace FF ones at the sector level both through a shift in innovation activities within existing firms and through firms׳ entry and exit. We use zero-inflated count data estimation techniques to identify the factors that affect specialized versus mixed firms׳ patenting behaviour both at the intensive (i.e., levels of innovation) and extensive (i.e., technological entry) margins. We further investigate the implications of our firm-level estimations for reducing the gap between REN and FF innovation at the aggregate level. We establish two key findings: (1) a decrease in the FF-REN technology gap mainly comes about through technological entry of specialized REN firms following an increase in REN market size; (2) increases in FF prices, FF market size, and FF knowledge stocks all increase the technology gap by increasing mixed firms FF innovation rates. An important implication of our results is that policies aimed at increasing REN innovation should focus on helping small firms to start and sustain innovation in the long-run.     

微生物燃料电池耦合连续搅拌反应系统(CSTR)低温下处理“糖蜜-电镀”废水

为提高传统微生物燃料电池(MFC)在低温条件下的效率,实现实验装置放大化.本实验将连续搅拌反应系统(CSTR)与双极室微生物燃料电池系统相结合,连续流处理糖蜜废水,并间接回收金属单质,处理模拟电镀废水,考察系统的产电性能和废水处理效果.结果表明,当系统稳定运行后,最高电压及功率密度分别可达到340 m V和58.65 m W·m-2.20 d后,系统COD去除率明显增加,最高COD去除率可达到81%.实验运行10 d后,银离子开始析出,最高去除率可达到90%左右.     

运行微生物燃料电池减排稻田土壤甲烷的研究

为了研究稻秆还田条件下运行微生物燃料电池(microbial fuel cells,MFCs)是否能有效减排稻田甲烷,本研究将添加质量分数0.5%稻秆的土壤装入MFCs反应器,淹水并种植水稻后运行MFCs.待水稻经历苗期、分蘗期、晒田期、灌浆期和成熟期共98 d后,停止MFCs运行.在MFCs运行过程中实时连续记录电压,每周一次采用静态箱法搜集并检测反应器的甲烷排放通量.结果表明,MFCs电流在分蘗期逐步升高并达到峰值,并且运行MFCs显著降低添加稻秆土壤在苗期和分蘗期的甲烷累积排放通量.原因可能与产电菌和产甲烷菌竞争有机底物有关.MFCs运行98 d后,水稻株高、地上和地下部分生物量,以及产量未受显著影响.本研究为稻田CH_4减排提供了一种潜在的绿色可持续的技术.     

生物表面活性剂强化剩余污泥微生物燃料电池产电特性研究

以剩余污泥为接种液和基质,探讨了添加生物表面活性剂(鼠李糖脂/TSS,0.3 g·g-1)对单室剩余污泥微生物燃料电池(SSMFC)产电特性及剩余污泥减量化的影响.结果表明,在一个运行周期中,对照组的产电周期为20 d,最大功率密度为236.8 mW·m-2,库仑效率为5.7%,TCOD去除率为28.6%,TSS去除率为28.9%,VSS去除率为33.4%,而实验组产电周期达到35 d,库伦效率为11.8%,最大输出功率密度为516.7 mW·m-2,较对照组增加了118.2%,TCOD、TSS、VSS去除率分别为58.5%、56.7%和66.3%,较对照组分别提高了104.5%、96.2%和98.5%.随着系统的运行,对照组和实验组系统输出电压均是先稳定一段时间后逐渐降低,污泥中SCOD、蛋白质和溶解性糖浓度均呈先上升再下降趋势.采用向剩余污泥中投加鼠李糖脂的方法可以增强SSMFC的产电效率,同时能显著增强剩余污泥减量化效果.