氢氧化镁共沉淀—导数示波极谱法测定水中微量铅镉

水样中加入氯化镁 ,调节溶液的pH =10 ,使水样中的微量元素铅和镉与氢氧化镁形成共沉淀而富集。沉淀经酸溶后 ,在盐酸—碘化钾—抗坏血酸—磷酸—酒石酸底液中 ,用示波极谱法连续测定铅和镉。方法的最低检出浓度铅为 0 .0 0 2mg L,镉为 0 .0 0 1mg L,11次测定的相对标准偏差 3 .1%～ 4.2 % ,标准回收率 96 .0 %～ 10 4 .0 %。     

石灰法中水深度处理技术

由中环(中国)工程有限公司开发的石灰法中水深度处理技术,适用于燃煤电厂的中水回用。主要技术内容一、基本原理利用石灰乳与废水里的CO2、HCO3-及金属离子等反应生成碳酸钙、氢氧化镁及磷酸钙等沉淀物,通过机械搅拌澄清池进行固液分离,最终实现去除废水中硬     

植物铝胁迫发生机制及其内在缓解途径研究进展

本文总结了土壤中铝的存在形式及其化学行为,分析了以针叶人工林为例的诱发植物铝胁迫效应的内外部机制,以及铝胁迫在不同生态水平上对植物生长的影响。比较了环境铝胁迫下,植物体自身缓解环境铝威胁的不同途径。     

依托高铝煤炭资源建立循环经济产业链

我国内蒙古自治区中西部和山西北部等地区高铝煤炭资源储量丰富,发电后产生大量高铝粉煤灰,可用于提取氧化铝,生产铝深加工产品,提取氧化铝过程中产生的固体废物和副产品可综合利用。分析了依托高铝煤炭资源,并以高铝粉煤灰提取氧化铝为核心打造循环经济产业链的必要性,以期实现高铝煤炭资源价值最大化,形成具有我国特色的煤炭—电力—有色冶金—化工—造纸—建材的循环经济产业链。     

染料废水脱色的物理化学处理技术

染料废水目前主要的脱色方法有吸附、混凝、氧化还原和生化法.活性炭吸附适用于低浓度的染料废水处理.聚硅硫酸铁混凝效果与Fe/SiO4摩尔比和pH值相关.氢氧化镁可有效去除印染废水中的直接红染料.有机絮凝剂往往需要和其它药剂复配.氧化法脱色率大,但成本高昂,且受染料废水的组成、氧化性及pH值影响.还原法药剂价格低廉,但还原降解产物具有毒性,必须经过二次处理.生物法成本较低,又受制于染料的生物降解性.因此发展多种手段联合应用已是当前染料废水处理的研究方向.     

石灰法中水深度处理技术

由中环(中国)工程有限公司开发的石灰法中水深度处理技术,适用于燃煤电厂的中水回用。主要技术内容一、基本原理利用石灰乳与废水里的CO2、HCO3-及金属离子等反应生成碳酸钙、氢氧化镁及磷酸钙等沉淀物,通过机械     

坏消息

我国4成儿童铝摄入量超标膨化食品是主要来源最近,有关专家通过近几年全国食品污染物监测网的数据和对加工食品中铝含量的专项监测,取得了11类食品6000多份的监测数据。数据显示,我国四成儿童铝摄入量超标。著名的营养与食品安全专家、中国工程院院士陈君石介绍说,儿童最主要的铝摄入量来自于膨化食品。铝的过量摄入将会引起婴幼儿的神经发育受损导致智力发育障碍。专家们根据评估结果对卫生部门提出了政策建议,卫生部也发布公函,对调整13种含铝添加剂的使用向社会征求意见。(正义网)     

层状双金属氢氧化物的制备方法及光催化应用

层状双金属氢氧化物是一类离子型的层状化合物。由于独特的物理片层结构、多样的化学成分组合(层板氢氧化物化学组成多样和层间阴离子可交换多样),使其在催化、吸附、光电化学、药物科学等领域都具有广泛的应用。首先,根据此化合物基本的化学性质,对其合成方法进行总结分类。然后,根据其良好的选择性和稳定性的特性,总结归纳基于层状双金属氢氧化的催化材料作为吸附剂和光催化剂的最新应用发展和改性方法。通过对理论基础的研究,进一步加快层状双金属氢氧化物材料在光催化技术领域的发展。     

高温低氧环境下铝、锌阳极在高盐度海水中的性能研究

为了明确铝阳极与锌阳极在工艺水舱等特殊环境下谁更适合使用。依照NACE TM 0190中牺牲阳极的电化学测试方法，对比研究了Al-Zn-In-Si阳极与Zn-Al-Cd阳极在高温低氧的高盐度海水中的电化学性能。在55℃低氧海水中，随着溶液盐度升高，铝阳极的电位有所负移，电化学效率急剧下降，腐蚀形貌越发不均匀；锌阳极的电位变化情况近似铝阳极，但电化学效率变化不大，且腐蚀形貌比较均匀。在特殊环境下，从电化学性能来看，锌阳极更适用。并且，不同盐度的溶液中，锌阳极与铝阳极的电位接近，不存在电位极性反转的情况。     

废铝塑分离技术获突破

日前,一项废铝塑包装的分离回收再利用技术研制成功.该技术使不易回收的废铝塑包装既能分离出塑料,又能制铝. 铝塑复合包装广泛用于食品厂、制药厂等众多行业的产品包装.且用量逐年递增,其废弃料、边角料逐年增加.由于铝与塑料粘在一起,既不能回收炼铝,也不能生产再生塑料,只能被废弃焚烧,既污染环境又浪费资源.研制者采用简易设备,运用“二次化学反应法”将铝塑分离成功,每吨废铝塑分离出0.85t再生塑料和0.1t废铝,既保护了环境,经济价值又明显增加了十几倍.(周树仁)     

建设用地使用权分层设立研究

由于历史、经济等各方面原因,我国建设用地使用权分层设立方面的研究刚刚起步,这方面的法律法规仍是空白,不足以保障我国土地空间资源分层开发利用的顺利进行.在对分层建设用地使用权内涵、性质进行深入阐述的基础上,在对我国建设用地使用权分层设立中可能产生的具体问题进行深入剖析,就建设用地使用权分层中存在的问题提出了切实可行的对策,以期对完善我国建设用地使用权分层设立的研究有所帮助.     

含高可溶性盐油田废水中悬浮物的测定

实验研究了可溶性盐对滤纸过滤法测定水中悬浮物的干扰，讨论了蒸馏水洗涤法消除可溶性盐干扰的不足。提出用双滤法消除可溶性盐干扰，通过室内和现场试验证明很有效。该法不改变原有的测定条件，具有较高的准确度和精密度。     

Book reviews

Book reviewd:
David Carle, Drowning the Dream: California's Water Choices at the Millennium
Cutler J. Cleveland, David Stern and Robert Costanza (eds), The Economics of Nature and the Nature of Economics
Sebastian Killinger, International Environmental Externalities and the Double Dividend
Michael A. Stocking and Niamh Murnaghan, Handbook for the Field Assessment of Land Degradation
Michael E. Soulé, Gordon H. Orians and P. Dee Boersma (eds), Conservation Biology. Research Priorities for the Next Decade     

Enhanced biogeochemical cycling and subsequent reduction of hydraulic conductivity associated with soil-layer interfaces in the vadose zone

Biogeochemical dynamics in the vadose zone are poorly understood due to the transient nature of chemical and hydrologic conditions but are nonetheless critical to understanding chemical fate and transport. This study explored the effects of a soil layer on linked geochemical, hydrological, and microbiological processes. Three laboratory soil columns were constructed: a homogenized medium-grained sand, a homogenized organic-rich loam, and a sand-over-loam layered column. Upward and downward infiltration of water was evaluated during experiments to simulate rising water table and rainfall events, respectively. In situ collocated probes measured soil water content, matric potential, and Eh. Water samples collected from the same locations were analyzed for Br, Cl, NO, SO, NH, Fe, and total sulfide. Compared with homogeneous columns, the presence of a soil layer altered the biogeochemistry and water flow of the system considerably. Enhanced biogeochemical cycling was observed in the layered column over the texturally homogeneous soil columns. Enumerations of iron- and sulfate-reducing bacteria showed 1 to 2 orders of magnitude greater community numbers in the layered column. Mineral and soil aggregate composites were most abundant near the soil-layer interface, the presence of which likely contributed to an observed order-of-magnitude decrease in hydraulic conductivity. These findings show that quantifying coupled hydrologic-biogeochemical processes occurring at small-scale soil interfaces is critical to accurately describing and predicting chemical changes at the larger system scale. These findings also provide justification for considering soil layering in contaminant fate and transport models because of its potential to increase biodegradation or to slow the rate of transport of contaminants.     

分层填料土地毛管渗滤系统脱氮作用研究

对土壤煤渣分层的土地毛管渗滤系统的脱氮效果和机理进行了研究。氮的静态吸附试验和土壤全氮含量分析表明,填料对氮的去除作用有限。植物对总氮的去除贡献率只占0.47%,作用不明显。温度和总氮去除率的相关分析表明,温度对总氮去除效果影响不显著。提高出水水位30 cm以创造适合反硝化菌生长的还原环境,总氮去除率由39.1%下降到30.0%,可见氧化还原条件不是系统反硝化反应的限制条件。投加葡萄糖作为碳源,使C/N〉3,有机物去除率保持在80%以上,总氮的去除率上升到52.4%,较高的C/N比能有效提高土地毛管渗滤系统的总氮去除效果。     

安徽省资源、环境、经济系统协调发展评价

以系统科学思想为基础，根据1990-2005年间安徽省的资源、环境与经济发展的实际情况，构建了一套分层次的协调发展评价指标体系，并运用主成分方法、坎蒂雷赋权法将相应层次的指标进行综合，根据协调发展的含义建立数学模型，从协调度、协调发展度、协调发展趋势指数的角度定量分析了安徽省资源、环境、经济系统协调发展的状况。该研究思路可作为其它地区在进行同类分析时提供参考。     

城市生活垃圾处理的环境污染分析

随着人口的增长和城市化的迅速发展,城市生活垃圾产量逐年递增,成分更加复杂.城市生活垃圾填埋过程中产生的渗滤液和焚烧过程产生的烟气对环境的污染极为严重,一定程度上已经制约了城市的可持续发展.通过分析渗滤液的产生及对环境的污染,提出了分层填埋控制和渗透反应栅格修复技术.对焚烧过程中的污染,通过焚烧前分类处理从源头上减少二次污染,同时对焚烧产生的烟尘和有毒有害物质进行物理化学方法的去除.     

EXPOSURE ASSESSMENT OF POPULATIONS USING ENVIRONMENTAL MODELING,DEMOGRAPHIC ANALYSIS,AND GIS1

ABSTRACT: Simulation of ground-water flow and fate of contaminants in the subsurface environment constitutes a major phase of most environmental assessment and site remediation studies. These simulation studies yield information on spatial and temporal distributions of contaminants in the subsurface media. An important use of this information is to conduct exposure assessment studies. Spatial and temporal distributions of both chemical concentrations and exposed populations render this integrated exposure analysis task rather difficult. Geographic Information Systems (GIS), on the other hand, provide a platform in which layered, spatially distributed databases can be manipulated with ease, thereby simplifying exposure analysis tasks significantly. In this paper, we describe procedures that combine the simulation models and demographic databases under a GIS platform to automate the exposure assessment phase of a typical health assessment study. Procedures developed herein significantly simplify the post-processing phase of the analysis, and render the overall task more ‘user friendly.’ A site-specific application is included as a demonstration of the proposed process.     

A Method for Designing Detection Monitoring Networks in Layered Aquifers with Non-uniform Flow

An integer programming method was devised to locate detection monitoring wells in layered aquifers. The method is applicable to aquifers with non-uniform groundwater flow, and it does not require that a compliance boundary be linear or perpendicular to the direction(s) of groundwater flow. In each layer, monitoring sites are defined along curvilinear transects that parallel equipotential lines. The model can be formulated to allocate wells to the transect with the highest detection efficiency, or to establish multiple lines of defense against contaminant migrating to a compliance boundary. Detection efficiencies of alternative monitoring transects are calculated from parameters obtained via numerical modeling of contaminant transport. These parameters include the narrowest plume that could traverse a monitoring transect, and the zone width of potential contaminant migration at the transect. Problem formulations are compact, and computational requirements are low relative to alternative approaches for designing detection monitoring networks in aquifers. An application to a glacial outwash aquifer demonstrates the utility of the method.