混合菌群生物燃料电池的产电机理与特性

利用厌氧污泥为接种源构建双室微生物燃料电池(Microbial fuel cell,MFC),研究其电子传递机制,并考察其底物利用谱及阴极电子受体对产电性能的影响.结果表明:该MFC主要通过生物膜机制实现电子从有机物到固体电极的传递过程.该混合菌MFC的底物利用谱范围广泛,单糖、二糖、小分子有机酸等有机物均可作为电子供体产电,其中以蔗糖和乳糖为底物产电效果较好,最大功率密度分别为69.69 mW/m2和60.75 mW/m2;而以乙醇为底物时,COD负荷最高,达123.55 mg L-1d-1.阴极不同电子受体对混合菌群MFC的产电性能也有显著影响,其中以KMnO4为电子受体电池性能最好,最大功率密度达1 396.74 mW/m2.     

Reductive Dechlorination of Tetrachloroethylene by Soil Sulfate-Reducing Microbes under Various Electron Donor Conditions

Biotransformation of tetrachloroethylene (PCE) by soil sulfate-reducing bacteria was investigated using acetate, lactate and methanol as electron donors. Results show that the effectiveness of biotransformation of PCE by soil sulfate-reducing bacterial is dependent upon the type of electron donor used.     

发挥电子信箱系统(E-mail)在环境信息传输中的作用

本文对目前环境信息的传播现状作了回顾,指出了实现办公自动化,利用电子信箱进行环境信息传输的必要性和紧迫性,进而对电子信箱的强大功能及在环境保护的有关领域的信息传输方面所能起到的较大作用进行了阐述,最后对电子信箱传输系统的建立即如何实现电子信箱的信息传输以及软、硬件的配置等作了介绍。     

微生物胞外电子传递过程强化机制及污染物高效转化

微生物水处理技术因运行成本低、处理量大、环境影响小等优点,被广泛的用于市政污水和工业废水的处理.微生物水处理的本质过程是生物催化氧化,涉及不同微生物种群间物质、能量和电子传输过程,而微生物胞外电子传递过程是影响其处理效率的关键因素之一.本研究立足于微生物氧化的原理,从介体材料强化、光电磁强化及微生物电化学强化等角度,系统论述了铁基材料、碳基材料、光、电、磁等对微生物电子传递过程的影响与机制.在此基础上,本论文总结了微生物电化学系统原理,分析了该系统中各类强化材料、强化技术对微生物胞外电子传递的影响,揭示了强化条件下污染物高效转化的作用机制,介绍了基于各种强化原理的系统构建因素及应用现状,并展望了该技术的发展趋势及存在的挑战.     

飞行时间二次离子质谱法在一次污染过程中PM2.5表面组分分析中的应用

团簇离子源的发明和使用,使飞行时间二次离子质谱（TOF-SIMS）法成为材料表面化学分析越来越重要的手段,TOF-SIMS法的主要测试功能包括表层质谱、化学成像及深度剖析3种。采用TOF-SIMS法对一次污染过程中的大气细颗粒物（PM_2.5）的表层进行检测,得到了PM_2.5表面成分的质谱及成像信息。结果表明：PM_2.5表层存在多种金属离子,通过扫描电子显微镜能谱仪的形貌与飞行时间二次离子质谱仪的成像亮度分析可知,K⁺、Na⁺、Mg²⁺响应强度相对较强,含量较高;通过原子吸收光谱仪进行金属离子定量可知,2018年11月4日和12月24日的K⁺、Na⁺、Mg²⁺的平均质量分别为1.809 5、0.443 8、1.526 2 mg;从形态分布上看,PM_2.5表面烟尘集合体含量较多,其次为燃煤飞灰、矿物颗粒和超细未知颗粒;PM_2.5表层的有机物离子C_xH_y片段也较多,经过m/z的测试数据进一步确定,表明颗粒物表层含有大量的脂肪烃和芳香烃;除此之外,还存在含N、O、S等的有机物和无机物。     

Phase separation and regrowth of aerosol matter collected after size fractionation in an impactor

Aerosol matter in the size range <2 μm was collected in a Berner impactor and subsequently analysed by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectrometry. Owing to the low electron beam energy of 5 keV (occasionally 10 keV), analysis was restricted to elements with atomic numbers 20 (Ca). Sub-micrometer aerosol matter was found to contain mostly S, O, and C as well as some K and Ca. Nitrogen appeared to escape detection, probably due to bombardment-induced sublimation of NO₃ and NH₄. During sampling at low to moderate relative humidity (<60%) the sulphur-rich fraction of the aerosol matter (most likely sulphates) regrew in the form of microcrystals with sizes up to 10 times larger than the mean aerodynamic diameter of the respective impactor stage. By contrast, when sampling during periods in course of which the relative humidity exceeded 70%, the aerosol matter regrew in the form of extended amorphous agglomerates. The aerosol deposits also contained large numbers of carbon nanoparticles, well separated from the regrown sulphate-rich matter. The nanoparticles were similar in size (20–40 nm), much smaller than the equivalent aerodynamic diameter of the impacting particles (63 nm–2 μm). Presumably, the carbon nanoparticles constituted the core of larger air-borne particles covered with sulphates (as well as with nitrates and organic carbon). The regrown microcrystals disappeared rapidly under electron bombardment at high current density, an observation that indicates high volatility at elevated temperatures. Aerosol matter collected in the size range between 1 and 2 μm contained large fractions of particles made of O, Si, P, K, and Ca (oxides). These particles were highly resistant to electron bombardment (hard) and showed little or no evidence for agglomeration or regrowth. After removing the soluble (acidic) material from the collected aerosol matter, only carbon nanoparticles and hard coarse particles were left behind. The observation of agglomerated or crystallized “soft” aerosol matter in combination with phase separation of carbon nanoparticles lends further support to the assertion that it is not possible to collect useful quantities of fine and ultrafine aerosol particles with as-suspended morphology. Some implications for health-related research are discussed.     

Environmental scanning electron microscopy as a new technique to determine the hygroscopic behaviour of individual aerosol particles

The hygroscopic behaviour of NaCl, (NH₄)₂SO₄, Na₂SO₄ and NH₄NO₃ particles in the size range of 0.1–20 μm was studied by environmental scanning electron microscopy (ESEM). This technique allows the in-situ observation of individual aerosol particles while changing the temperature and/or relative humidity (RH) in the sample chamber. The hygroscopic behaviour of these particles (e.g., deliquescence, adsorption of water on the particle surface) becomes directly observable with a lateral resolution of the order of 8–15 nm. The deliquescence relative humidities (DRH) of the different salts, the temperature dependence of the DRH for NH₄NO₃, and the growth factors (at increasing relative humidities) for NaCl were determined. Generally, a good agreement between the values obtained by ESEM and those found in literature was achieved. However, the DRH of NaCl determined by ESEM is systematically higher (approximately 2%, absolute) than the values obtained by other techniques, which can be explained by the observed strong absorption of water onto the crystal surface prior to droplet formation. The efflorescence behaviour of individual particles can be studied only qualitatively due to influences of the sample substrate. Furthermore, it is demonstrated that the activation of soot can be studied at high resolution by ESEM.     

SBBR工艺反硝化过程中N_2O和NO的产生情况

利用序批式生物膜反应器(SBBR),以葡萄糖为碳源(COD为500 mg/L),考察了不同碳氮比(COD与TN之比)、不同电子受体(NO_2~-或NO_3~-)、不同投加方式(碳源与氮源同步投加或投加碳源60 min后再投加氮源的异步投加)对N_2O产生情况的影响,以及碳氮比为2时NO的产生情况。实验结果表明:不论同步投加还是异步投加,两种电子受体的N_2O-N生成率均随着碳氮比的增大而下降;不同碳氮比下,投加NO2-时的N_2O-N生成率均高于投加NO3-时,异步投加时的N_2O-N生成率均大于同步投加时。说明低碳氮比、高浓度NO2-和胞内贮存物作碳源是反硝化过程中N_2O产生和大量积累的关键因素。此外,NO2-为电子受体时的NO-N生成率高于NO3-为电子受体时。     

基于SEM-EDS的大气降尘特征及来源解析——以荒漠草原区井工开采煤炭基地为例

利用场发射扫描电子显微镜-配能谱分析系统（SEM-EDS）于2019年3~5月对荒漠草原区煤炭基地及其周边5个功能区（煤炭工业区、煤炭运输道路、电力工业区、商住区和沙区）共计23个大气降尘样品的粒径特征、微观形貌、单颗粒能谱图进行检测分析.结果表明,各功能区大气降尘中颗粒物总体形貌基本相似,均包括近球状、类椭球状、颗粒状、块状和柱状/片状颗粒物以及烟尘集合体.此外,煤炭运输道路、电力工业区和商住区还存在球状颗粒物.各功能区大气降尘以>10μm颗粒物为主,其中,电力工业区、商住区、沙区和煤炭工业区大气降尘平均粒径均>100μm,且总量超过65%,煤炭运输道路大气降尘平均粒径为67.59μm,粒径>50μm的颗粒物量占53%.大气降尘主要由细粉砂、粗粉砂和细砂组成.大气降尘中颗粒物的类型包括存在于各功能区中的硅酸盐矿物（石英、钾长石和斜长石）、碳酸盐矿物（方解石和白云石）、硫酸盐矿物（石膏）和高岭石,存在于煤炭运输道路、煤炭工业区和电力工业区中的富铁颗粒,存在于煤炭工业区中的铁镁颗粒,存在于煤炭运输道路、煤炭工业区、电力工业区和商住区中的烟尘集合体和燃煤飞灰.大气降尘来源主要为本地源,包括各功能区中均存在的地表扬尘、工业扬尘、建筑扬尘和大气中二次化学反应产物,煤炭运输道路、煤炭工业区和电力工业区中存在的机动车零件磨损产物,以及煤炭运输道路、煤炭工业区、电力工业区和商住区中存在的机动车尾气排放和燃煤产物.     

ESR技术应用于逆胶束酶体系性能的研究

采用鼠李糖脂构建逆胶束体系,并利用电子自旋共振（ESR）技术研究了鼠李糖脂逆胶束及鼠李糖脂逆胶束酶体系的性能.采用ESR光谱技术计算得出逆胶束体系中超精细分裂常数变化,研究表明鼠李糖脂在正己烷中的临界胶度为0.07mmol/L.通过分析ESR光谱中旋转相关时间的变化,探究电子自旋探针在逆胶束中运动受阻和翻转所需时间的情况同时,ESR光谱的峰值体现了样品中自由基含量的多少.通过对比逆胶束体系、逆胶束酶体系以及逆胶束酶-苯酚体系的ESR光谱,结果表明鼠李糖脂逆胶束-苯酚体系的自由基最多.通过研究对16-氮氧自由基硬脂酸对两个体系作用,推测出电子自旋探针自由基团定位于逆胶束水核中,并且推断电子自旋探针位于水核的边缘区域,即结合水水层.该研究为逆胶束酶体系的应用提供了坚实的理论基础.