Particulate matter pollution in Kunshan High-Tech zone: Source apportionment with trace elements, plume evolution and its monitoring

Particulate matter(PM) in the Kunshan High-Tech zone is studied during a three-month campaign. PM and trace elements are measured by the online pollution monitoring, forecastwarning and source term retrieval system AS3. Hourly measured concentrations of PM_(10), PM_(2.5) and 16 trace elements in the PM_(2.5) section(Ca, Pb, Cu, Cl, V, Cr, Fe, Ti, Mn, Ni, Zn, Ga, As, Se, Sr, Ba)are focused. Source apportionment of trace elements by Positive Matrix Factorization modeling indicates that there are five major sources, including dust, industrial processing, traffic,combustion, and sea salt with contribution rate of 23.68%, 21.66%, 14.30%, 22.03%, and 6.89%,respectively. Prediction of plume dispersion from concrete plant and traffic emissions shows that PM_(10) pollution of concrete plant is three orders of magnitude more than that of the traffic. The influence range can extend to more than 3 km in 1 hr. Because the footprint of the industrial plumes is constantly moving according to the local meteorological conditions, the fixed monitoring sites scattered in a few hundred meters haven't captured the heaviest pollution plume at the local scale of a few km~2. As a more intensive monitoring network is not operationally possible, the use of online modeling gives accurate and quantitative information of plume location, which increases the spatial pollution monitoring capacity and improves the understanding of measurement data. These results indicate that the development of the AS3 system, which combines monitoring equipment and air pollution modeling systems, is beneficial to the real-time pollution monitoring in the industrial zone.     

Alkali resistance promotion of Ce-doped vanadium-titanic-based NH3-SCR catalysts

The effect of K deactivation on V_2O_5/WO_3-TiO_2 and Ce-doped V_2O_5/WO_3-TiO_2 catalysts in the selective catalytic reduction(SCR) of NOxby NH_3 was studied.Ce-doped V_2O_5/WO_3-TiO_2 showed significantly higher resistance to K deactivation than V_2O_5/WO_3-TiO_2.Ce-doped V_2O_5/WO_3-TiO_2 with K/V = 4(molar ratio) showed 90% NOxconversion at 350°C,whereas in this case V_2O_5/WO_3-TiO_2 showed no activity.The fresh and K-poisoned V_2O_5/WO_3-TiO_2 and Ce-doped V_2O_5/WO_3-TiO_2 catalysts were investigated by means of in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS),NH_3-temperature progress decomposition(NH_3-TPD),X-ray photoelectron spectroscopy(XPS) and H2-temperature program reduction(H_2-TPR).The effect of Ce doping on the improving resistance to K of V_2O_5/WO_3-TiO_2 were discussed.     

A comprehensive classification method for VOC emission sources to tackle air pollution based on VOC species reactivity and emission amounts

In China, volatile organic compound(VOC) control directives have been continuously released and implemented for important sources and regions to tackle air pollution. The corresponding control requirements were based on VOC emission amounts(EA), but never considered the significant differentiation of VOC species in terms of atmospheric chemical reactivity. This will adversely influence the effect of VOC reduction on air quality improvement. Therefore,this study attempted to develop a comprehensive classification method for typical VOC sources in the Beijing–Tianjin–Hebei region(BTH), by combining the VOC emission amounts with the chemical reactivities of VOC species. Firstly, we obtained the VOC chemical profiles by measuring 5 key sources in the BTH region and referencing another 10 key sources, and estimated the ozone formation potential(OFP) per ton VOC emission for these sources by using the maximum incremental reactivity(MIR) index as the characteristic of source reactivity(SR). Then, we applied the data normalization method to respectively convert EA and SR to normalized EA(NEA) and normalized SR(NSR) for various sources in the BTH region.Finally, the control index(CI) was calculated, and these sources were further classified into four grades based on the normalized CI(NCI). The study results showed that in the BTH region,furniture coating, automobile coating, and road vehicles are characterized by high NCI and need to be given more attention; however, the petro-chemical industry, which was designated as an important control source by air quality managers, has a lower NCI.     

北极新奥尔松地区土壤及沉积物中可培养细菌多样性及分布特征分析

以2010年中国北极黄河站科学考察从新奥尔松地区采集的2个土壤和8个不同类型的沉积物样品为研究对象,采用分离培养方法及16S rRNA基因序列测定分析可培养细菌的多样性。对从10个站位分离出的343株细菌进行菌落特征分析,选取47株代表性细菌进行16S rRNA基因的分子鉴定并构建系统发育树,结果表明47株细菌归属于4个门,6个纲,18个属和29个种。在属水平上,芽孢杆菌纲细菌的多样性最为丰富,共6个属;在菌株数量上,γ-变形菌纲属于优势类群,共27株,分属于13个种。北极新奥尔松地区可培养细菌在海洋沉积物、湖泊沉积物、河流沉积物及土壤中的种属构成存在差异,其中海洋沉积物中细菌多样性最为丰富,而湖泊沉积物中细菌多样性次之。     

油菜硒的富集特征及其与土壤硒的关系

为系统研究油菜对硒的富集特征及其与土壤硒形态间的关系,采用人工添加外源硒(0、0.5、5.0 mg·kg~(-1)土壤)的方式,构建了土壤含不同浓度硒的大田实验系统.测定了成熟期油菜不同部位硒总量、籽粒中有机小分子硒化合物及根际土壤中各形态硒的含量.明确了硒在油菜体内的富集特征;分析了籽粒中硒含量同其他组织部位及土壤硒含量间的关系;深入解析了土壤各形态硒对油菜硒的贡献.结果表明,随土壤硒浓度的增加,由根部向地上部转移的硒的比例增大;土壤高浓度(5.0 mg·kg~(-1))硒处理下,更大比例的硒富集于角果壳和籽粒中;硒代蛋氨酸、硒代半胱氨酸是籽粒中主要形态的有机小分子硒化合物;各浓度硒处理土壤中,均以铁锰氧化物结合态为主,占土壤总硒的87.24%~97.40%;籽粒硒含量与其他组织部位硒及土壤硒含量呈显著相关;茎干中硒与根系中硒含量呈正相关,而茎干中硒又是角果壳硒的主要贡献因子,茎干和角果壳硒对籽粒硒具有同等贡献.研究结果明确了油菜对硒的富集特征及其与土壤硒形态间的关系,有助于通过土壤中硒形态和植物营养器官中硒含量来评估籽粒中硒含量.     

投加颗粒活性炭强化餐厨垃圾的厌氧处理

通过投加颗粒活性炭（GAC）强化直接种间电子传递（DIET）进而提升餐厨垃圾的厌氧产甲烷处理效能,并研究了GAC投加导致的微生物群落变化.研究发现,投加了GAC的实验组反应器能够在更高的有机负荷下（10.4kgCOD/（m³·d））稳定运行并维持较高的甲烷产率,不投加GAC的对照组在有机负荷7.8kgCOD/（m³·d）时甲烷产率及pH值均明显降低,挥发酸大量积累,反应器酸化崩溃.微生物群落结构分析发现,GAC表面富集了大量可以胞外电子传递的细菌（占细菌丰度的34%）和可以参与DIET的产甲烷菌（占古菌丰度的88%）,表明GAC的加入可以有效富集这两类微生物的生长,并可能通过GAC强化DIET促进了餐厨垃圾的厌氧消化.     

某退役溶剂厂有机物污染场地燃气热脱附原位修复效果试验

热脱附技术一般用于土壤中有机物的异位修复,然而对于受有机物污染较深土壤的原位修复却鲜有报道.本文以某退役溶剂厂土壤中苯、氯苯和石油类为目标污染物,运用燃气热脱附技术进行原位修复.本文介绍了燃气热脱附技术的工艺设计流程,针对场地目标污染物进行燃气热脱附的工程化试验,结果显示热脱附处理后土壤中苯、氯苯和石油类最高去除率接近100%.本文还探讨了温度、停留时间、土壤含水率和土壤质地对热脱附效率的影响,发现在温度和停留时间相同情况下,含水率较小、孔隙率较大的粉砂土热脱附效果更好.试验表明,燃气热脱附原位修复技术处理场地挥发性有机污染物效果良好,可以进行大规模的实际运用.     

基于恢复效度的三峡升船机驱动系统失效危害性TOPSIS评估

三峡升船机驱动系统故障模式的危害性直接关系到升船机的安全运行。为判定故障模式危害度等级,根据运行情况,结合同类型升船机,选取了驱动系统的5类故障模式;引入恢复效度的概念,运用德尔菲法对恢复效度、发生频度、严酷度和可探测度进行等级划分并利用AHP法确定各评估指标的权重;最后通过TOPSIS方法建立了数学模型,对三峡升船机驱动系统故障模式的危害性进行了分析、排序和验证。结果表明:恢复效度与故障危害性关联最为密切,齿轮和齿条故障对升船机的危害性最大,其次分别是减速器、同步轴系统、小齿轮托架以及万向轴等。此方法为有针对性的制定相关弥补措施和对策提供了依据,也为三峡升船机其他关键机构失效危害性分析提供了参考。     

活性炭吸附苯过程工艺参数实验和数值模拟研究

吸附法可适用于各种浓度范围VOCs的治理。本文采用实验和数值的方法研究了活性炭吸附苯过程工艺参数。首先采用实验方法得到了一种工况下的穿透时间,然后基于多孔介质模型和组分输运模型建立U型管内活性炭吸附苯过程三维数学模型。数值计算得到的穿透时间和实验结果对比误差为1.41%,证明数学模型可靠。另外,本文对模型进行了网格无关性验证。最后,采用该数学模型研究了入口速度、入口苯质量分数和多孔介质孔隙率对穿透时间、吸附过程最高温度和U型管内温度分布等参数的影响规律。