改性天然高分子絮凝剂和聚合氯化铝复合沉降与絮体分形

在改性天然高分子絮凝剂(CMS)和聚合氯化铝(PAC)复合处理有机废水絮体沉降速度的实验中,用显微镜和电镜观察到絮凝物是有自相似特征的不规则形状,具有分形特征.在pH值为6.86、聚合氯化铝(PAC)加入量为80mg/L条件下,天然改性高分子药剂加入量为1.5mg/L时沉降效果最好,与单独加入PAC相比20min时平均沉降速度分别为2.6mm/min和1.7mm/min.并计算出此时复合处理形成絮凝体的分维数为1.70.     

固定床PVC燃烧脱氯的机理和试验

研究垃圾组分PVC在焚烧过程中HCl的排放和脱除特性的实验在准等温、电加热的水平石英管反应器中进行.随着床温从700℃升高到900℃,HCl的转化率从82.5%平缓增加到88.3%,而过量空气系数的增加促使部分HCl转化为C1₂(1.9%～4.5%)的形式存在.钙基吸收剂CaCO₃,Ca(OH)₂,Ca(CH₃COO)₂对HCl的脱除效率高达68%～79%,而镁基吸收剂的脱氯效率却低于3%.小的吸收剂粒径、高的Ca/Cl比会促进脱氯效率的提高;烟气中CO₂和H₂O对脱氯效率的影响与它们在反应平衡中所起作用有关.高温下燃烧固氯机理反应的平衡常数的计算不仅诠释了实验结果,而且提供了脱氯吸收剂选择的依据.     

施用制革污泥土壤中铬的积累、化学形态及其植物有效性

通过对施用制革污泥土壤中铬的含量和形态、作物中铬积累量的测定,结合小麦幼苗培养试验,对Cr的化学形态与植物有效性的关系进行了研究.结果表明,施用污染后2mol/L HCl浸提态Cr的大幅度增长可能是造成作物Cr含量增加的主要原因,当土壤中Cr含量为220mg/kg时,小麦植株达到最大吸收量23.5mg/kg.高浓度Cr投入2种不同土壤时,小麦与水稻茎叶中Cr含量基本一致,而籽粒中含量则随作物种类有较大变化.     

ECD氧气诱导法分析大气中痕量HCFC-22

HCFC-22(CHClF₂)是CFC-12的主要替代物,它在大气中的体积分数仅为10^-12级.而且对ECD检测器响应灵敏度很低.本文经过低温浓缩进样后采用氧气诱导法来增强ECD对它的分析灵敏度,载气中氧气的体积分数为0.54%时,信噪比最大,此时ECD灵敏度增强约500倍.结合该条件下ECD温度选择、程序升温和载气流量的研究,建立了高灵敏度ECD气相色谱测定大气中HCFC-22浓度的实用分析方法.     

应用化学质量平衡模型解析烟台市污染源的排放贡献率

根据烟台地区污染排放特点,应用化学质量平衡模型（CMB8）进行污染源解析分析,得出每个污染源对于受体地区颗粒物体样本的排放贡献率。最终的模型结果显示,建筑尘和居民烯煤锅炉排放,海洋尘和冶炼厂排放对于大气环境污染也有一定的贡献,以上分析可以为城市污染源治理提供一定的依据。     

电化学催化降解苯胺的试验研究

用新兴的电化学催化系统,以采用特殊工艺自制的DSA类电极为阳极,对自配的苯胺溶液进行了降解处理,并得出了本试验范围内的最佳条件。     

Metallakkumulation in Moosen: Standörtliche und regionale Randbedingungen des Biomonitoring von Luftverunreinigungen

Goal and Scope

Several studies show that the concentration of metals in mosses depends not only on metal deposition but also on factors such as moss species, canopy drip, precipitation, altitude, distance to the sea and the analytical technique used. However, contrasting results have been reported and the interpretation of the spatial variability of the metal accumulation in mosses remains difficult. In the presented study existing monitoring data from the European Heavy Metals in Mosses Surveys together with surface data on precipitation, elevation and land use are statistically analysed to assess factors other than emissions that have an influence on the metal accumulation in the mosses.

Main Features

Inference statistics and Spearman correlation analysis were applied to examine the association of the metal accumulation and the distance of the monitoring sites to the sea as well as the altitude. Whether or not significant differences of the metal loads in the mosses exist at national borders was examined with help of the U-test after Mann and Whitney. In order to identify and rank the factors that are assumed to have an influence on the metal uptake of the mosses Classification and Regression Trees (CART) were applied.

Results

No clear tendency could be derived from the results of the inference statistical calculations and the correlation analyses with regard to the distance of the monitoring site to the sea and the altitude. According to the results of the CART-analyses mainly the moss species, potential emission sources around the monitoring sites, canopy drip and precipitation have an effect on the metal bioaccumulation. Assuming that each participating country followed strictly the manual for sampling and sample preparation the results of the inference statistical calculations furthermore suggest that in most cases different techniques for digestion and analysis bias the measurements significantly.

Discussion

For the first time a national monitoring data base consisting of measurement data and metadata as well as surface information on precipitation, land use and elevation was applied to examine influence factors on the metal bioaccumulation in mosses. The respective results mirror existing knowledge from other national studies to a large extend, although further analyses are necessary to affirm the findings. These analyses should include data from other national monitoring programmes and should additionally be carried out with other decision tree algorithms than CART.

Conclusions

The local variability in the metal concentration in mosses can be uncovered in terms of predictors or underlying hidden causes by using CART. Ideally, such an approach should be applied across the whole of Europe. This will only be feasible if all participating countries provide additional information about site characteristics as currently is done in for example the German moss surveys.

Recommendations

The UNECE Metals in Mosses Survey experimental protocol should be improved in order to reduce the observed influences, to enhance standardisation, and to strengthen the quality control. This implies the integration of sampling site describing metadata into the assessment. Furthermore, basis research is needed to test the hypothesis concerning moss species-specific accumulation of depositions.

Perspectives

Provided that the presented results hold true in further analyses correction factors should be applied on the moss data in order to get the depicted spatial patterns and temporal trends of metal bioaccumulation unbiased. Such factors should be calculated for natural landscape units or ecoregions that are homogeneous with regard to climate, vegetation and altitude.     

黄土高原地区水资源承载力动态变化及灰色拓扑预测——以山西、陕西、宁夏、甘肃四省为例

研究水资源承载力对促进区域水资源的合理开发和保证经济可持续发展具有十分重要的作用.文章采用模糊综合评价方法,以水资源利用率、降水量、人均占有水量和生态用水量作为评价因素,首次对黄土高原水资源承载力进行了大尺度综合评价,并建立灰色拓扑预测模型对其动态变化进行预测,在此基础上提出了黄土高原水资源可持续利用对策.结果表明:黄土高原四省水资源承载力在1994-2004年间总体上呈缓慢上升趋势,水资源开发潜力呈微弱增大趋势;但值得注意的是,黄土高原水资源开发已有一定规模,其水环境仍十分脆弱,需要进一步作好节水和水资源的保护工作.     

城市大气中NOx和CO对质子交换膜燃料电池性能的影响研究

研究了城市主要大气污染物NOx和CO对质子交换膜燃料电池(PEMFC)性能的影响.电池恒流放电下的电压-时间曲线、极化曲线显示,体积分数为1×10-4左右的NOx对单电池性能造成严重的影响,但这种影响是可逆的.与此不同的是,往阴极通入7.9×10-5至1.56×10-3三种不同体积分数的CO65 h后,电池性能没有明显的下降.气相色谱和质谱数据表明,Pt能快速将空气中的CO氧化成CO2.     

接触氧化-人工湿地去除印染废水中的COD

采用絮凝沉淀+接触氧化+人工湿地工艺处理印染废水中COD研究。结果表明,斜板沉淀池出水COD平均值为1322mg/L,此间COD去除率为38·6%;二沉池出水COD平均值为71mg/L,此段COD去除率达94·6%;人工湿地出水COD平均值为37mg/L,人工湿地COD去除率为48·0%。处理设施COD总去除率98·3%。