MnO2表面结合Fe(Ⅱ)对三氯乙烯的还原脱氯作用

通过批量实验研究了Fe(Ⅱ)、MnO2和MnO2表面吸附Fe(Ⅱ)这3种体系对溶液中三氯乙烯的还原脱氯作用。发现Fe(Ⅱ)吸附在MnO2表面时,对三氯乙烯的脱氯作用最强,氯代降解产物为顺-二氯乙烯(cis-DCE),且反应符合准一级动力学。进一步实验表明,保持Fe(Ⅱ)浓度为1 mmol/L,反应速率常数kobs和三氯乙烯去除率随pH升高(5.0～9.0)而增加,最大值分别为1.62×10-1h-1、70.4%;固定pH=7.0,kobs和三氯乙烯去除率随其Fe(Ⅱ)浓度增加(1～3mmol/L)而增大。Fe(Ⅱ)浓度继续增加,kobs和三氯乙烯去除率反而减小。pH=7.0,Fe(Ⅱ)浓度为3 mmol/L时,kobs和三氯乙烯去除率达到最大值,分别为2.86×10-1h-1和85.7%。     

自由旋片除雾器脱水性能实验研究

提出一种新型除雾装置——自由旋片除雾器。在实验室条件下,从除雾效率、压力损失两方面研究了自由旋片除雾器的性能。实验结果表明,风速在11 m/s左右时,自由旋片除雾器的除雾效率达到最大值。对比实验发现,自由旋片除雾器的除雾效率远高于固定叶片除雾器的除雾效率,二者的除雾效率最大值相差约10%。自由旋片除雾器的除雾效率变化曲线在6~13 m/s的流速范围内相当平滑,说明自由旋片除雾器对含雾气流流速的波动有很好的适应性。另外,增加液气比和雾滴粒径会提高自由旋片除雾器的除雾效率。自由旋片除雾器压力损失系数仅为4.3,而固定叶片除雾器压力损失系数为6.6。所以,自由旋片除雾器的阻力特性远优于固定叶片除雾器。     

自由旋片除雾器内气液两相流场数值模拟

为了给自由旋片除雾器结构优化设计提供理论依据,运用CAD软件建立了自由旋片除雾器的简化三维模型,运用RNGk-ε湍流模型模拟了自由旋片除雾器内部三维两相流场,得到压力场、速度场分布。结果表明,叶轮轮毂前形成局部高压区,轮毂后形成局部低压区,轮毂后有回流存在。叶轮后气流的旋转运动是由旋片的仰角引起的,而与叶轮旋转无关。当入口速度在11.5 m/s时,旋片后的最大切向速度达到20 m/s。这一现象有利于气液离心分离的实现。叶轮迎风面大部分气流的运动方向与叶轮旋转方向相反,背风面气流运动较复杂,在靠近旋片中心处存在局部涡流。对液滴相运动轨迹模拟表明,自由旋片除雾器能有效实现气液分离。     

Effect of recent climate change on Arctic Pb pollution: a comparative study of historical records in lake and peat sediments

Historical changes of anthropogenic Pb pollution were reconstructed based on Pb concentrations and isotope ratios in lake and peat sediment profiles from Ny-?lesund of Arctic. The calculated excess Pb isotope ratios showed that Pb pollution largely came from west Europe and Russia. The peat profile clearly reflected the historical changes of atmospheric deposition of anthropogenic Pb into Ny-?lesund, and the result showed that anthropogenic Pb peaked at 1960s-1970s, and thereafter a significant recovery was observed by a rapid increase of (206)Pb/(207)Pb ratios and a remarkable decrease in anthropogenic Pb contents. In contrast to the peat record, the longer lake record showed relatively high anthropogenic Pb contents and a persistent decrease of (206)Pb/(207)Pb ratios within the uppermost samples, suggesting that climate-sensitive processes such as catchment erosion and meltwater runoff might have influenced the recent change of Pb pollution record in the High Arctic lake sediments.     

Distribution pattern of plant species diversity in the mountainous Region of Ili River Valley, Xinjiang

In this paper, detrended canonical correspondence analysis was performed to analyze the relationships between diversity indices and environmental gradients, generalized additive model was employed to modal the response curves of diversity indices to the elevation, based on data from field investigation in the mountainous region of the Ili River Valley and a survey of 94 sample plots. Two hundred fifty-nine plant species were recorded in the 94 sample plots investigated, up to 235 species all appeared in the herb layer, and the species of woody plants were very limited. The communities with a complicated vertical structure presented higher values of indices. The distribution pattern of plant species diversity on the northern slope was affected by such factors as elevation, slope aspect, slope gradient, total nitrogen, total potassium, soil water content, organic matter, and that on the southern slope was mainly affected by such factors as slope gradient, elevation, available phosphorus, and soil water content. On the northern slope, Patrick index and Shannon?CWiener index of the plant communities presented a bimodality pattern along altitude; Simpson index and Pielou index showed a partially unimodal pattern. On the southern slope all the distribution pattern of species diversity indices showed two peaks, though Patrick index??s bimodality pattern was not an obvious one. These altitudinal patterns were formed by the synthetic action of a variety of environmental factors with elevation playing an important role.     

钱塘江富阳-杭州段沉积物磷的赋存形态分析

研究了钱塘江富阳一杭州段10个采样点表层沉积物中TP、各组分磷的含量分布以及沉积物有机质和粒径对磷分布情况的影响.结果表明,钱塘江富阳一杭州段表层沉积物中的TP为594.76～1 463.06 mg/kg,平均为940.24 mg/kg.NaOH提取态磷(NaOH-P)是污染河段无机磷(IP)的主要赋存状态.除个别采样点外,有机磷(OP)在TP中所占的比例相对较低.钱塘江富阳一杭州段沉积物TP以及赋存状态与沉积物粒度组成及有机质含量有显著的相关关系,沉积物中细颗粒越多,有机质含量越高,其TP也就越高,污染河段磷素增加主要造成NaOH-P升高,因此可以判断河段释磷潜力与污染有关.     

上海大气颗粒物中六溴环十二烷的污染特征及人体呼吸暴露水平

利用液相色谱-串联质谱研究了2008年上海市全年大气颗粒物中六溴环十二烷(HBCDs)的污染水平和异构体组成特征,在此基础上进一步运用风险商评估了上海市人群每日通过大气吸入HBCDs的非致癌风险.结果表明,城郊采样点宝山(BS)大气颗粒物中HBCDs的年平均浓度为30.20 pg·m-3,城区采样点徐家汇(XJH)大气颗粒物中HBCDs的年平均浓度为18.55 pg·m~(-3),城郊采样点的浓度显著高于城区采样点(p0.01);与国内外其它研究区域相比,上海大气中HBCDs的污染总体处于较低水平;上海市大气颗粒物中HBCDs异构体组成与工业品中HBCDs的组成呈现出明显差异,α-HBCD的比例显著升高,发生了异构体转化;上海市人群每日呼吸暴露剂量远低于文献中的参考值,非致癌风险商(HQ)介于10~(-4)~10~(-5)之间,非致癌健康风险较小,表明在上海市大气颗粒物中HBCDs的呼吸暴露为低风险.     

论多中心环境行政范式的建立与温州模式的拓展研究

以温州模式为媒介,探讨多中心环境行政范式建立及环保与经济一体化构建问题,并从环境立法及环境管理视角研究温州经济与环保双赢范式,以求打破以往温州模式研究视角与领域的桎梏,也为建构和谐社会提供一个视角。     

负载型TiO2/活性炭光催化灭活大肠杆菌(E.coli)的研究

以大肠杆菌(Escherichia coli JM 109)为研究对象,通过细菌的灭活实验研究负载型TiO2/活性炭(TiO2/AC)的灭菌性能,并利用XRD、BET和SEM对材料的晶型、晶粒尺寸、比表面积和吸附在材料上的细菌分布形态及数量进行分析.结果表明吸附在TiO2/AC上的大肠杆菌数比吸附在活性炭和TiO2都多.TiO2/AC对E.coli光催化灭活率比TiO2粉末和P25高,制备材料的热处理温度500℃和光催化反应中光强40 W都分别使TiO2/AC的光催化活性达到最大,在光催化灭活E.coti过程中,KH2PO4使催化剂活性降低程度比NaHCO3大,而两者使TiO2/AC催化活性降低程度比TiO2小,但NaHCO3对催化活性的影响是可逆的.     

开封市声环境质量状况及对策

以开封市近年来对环境噪声的监测资料,分析了声环境质量状况,并结合污染现状提出了防治对策。