Pd/Ti电极上2,4,6-三氯酚还原脱氯:条件优化及降解途径

利用电沉积法制备了Pd/Ti电极,用于2,4,6-三氯酚(2,4,6-TCP)的电还原脱氯.采用单因素实验和响应面分析法,探讨了2,4,6-TCP脱氯试验条件;根据实验结果,拟合出了脱氯中各步骤的反应速率常数.结果表明,2,4,6-TCP初始浓度为80mg/L时,优化的脱氯参数为电流为5mA,支持电解质Na2SO4浓度为0.05mol/L,阴极电解液初始pH值为2.40.在优化条件下, 2,4,6-TCP在80min内完全脱氯; 2,4,6-TCP的还原脱氯符合准一级反应动力学,主要脱氯途径为2,4,6-TCP→2,6-DCP→2-CP→苯酚.     

红壤稻田系统水分和养分转换效益研究

田间模拟施肥和水分管理模式的定位试验结果表明：施肥和水分管理模式显著地影响水分和养分的转化和生产效益。单施N的产量效应为4.5 kg/kg,而NP或NPK配施养分的产量效应分别为8.8 kg/kg和8.0 kg/kg;有机物料循环的增产率为56.5%;在有机物循环的基础上配施NPK化肥最大的增产率可达79.8%。常规灌溉年需水量为5 838 m3/hm2,田间水分分配为：蒸散占1/2,翻耕整地占1/6,植物构成占1/21,田间渗漏占1/14,其它环境耗水(维持)占1/5。晚稻灌溉占全年的71%,7～9月是灌溉需水高峰期,占全年灌溉量的68%。生产灌溉效率：生物量3.67 kg/m3,精谷量1.48 kg/m3。双季稻生产的灌溉,以早稻保持水层灌溉,晚稻按需配额灌溉的模式比较适宜。     

海藻酸钠固定化纳米铁还原脱色活性红X3B

采用海藻酸钠固定纳米铁制备海藻酸钠纳米铁小球,研究了海藻酸钠浓度、纳米铁含量、活性红X3B浓度、反应温度、pH值等对海藻酸钠固定化纳米铁小球还原活性红X3B的影响.采用高效液相色谱（HPLC）、紫外可见分光光度计（UV-Vis）、扫描电镜（SEM）、透射电镜（TEM）等方法分析污染物的还原脱色过程.结果表明,X3B的还原脱色获得了较好的效果,当温度25.0℃,海藻酸钠浓度2.0%,纳米铁含量2.0g/L,转速200r/min,pH值10.9时,反应720min后,25.0mg/L活性红X3B的脱色率达98.9%.海藻酸钠凝胶对活性红X3B没有吸附作用,海藻酸钠固定化纳米铁小球降解活性红X3B的主要机制为纳米零价铁的还原作用.     

深圳市高层建筑地震安全指数判定系统

以深圳市高层建筑为研究实例,介绍了香港大学的城市灾害损失评估及应急反应管理系统,并采用此系统内置的建筑易损性分析模块,结合泛珠三角地区灾害危险性概率模式,场地特征及高层建筑实地调查分析结果,从建筑安全性角度对深圳市的标志性建筑进行危险性分析,进而对深圳市应对突发性灾难事件的管理建设提出建议。作为应用实例,模拟一定概率条件下的灾难事件发生时的建筑物损坏情况,归纳出高层建筑的损坏模式,总结深圳市高层建筑的安全性隐患,提出目前防灾减灾急需实施的相应步骤:建议在一元化的城市灾害预警和应急指挥体系下,整合各个灾种防灾减灾管理部门的资源,以科学分析软件为灾情模拟和决策预案制定的工具,使危机处理的理念由领导决策型转向科学分析型,加强城市应对面对突发事件的能力,保障经济与社会的持续稳定发展。     

Studies of Thermal Transformations of Humic and Fulvic Acids in Soils I. Infrared Spectroscopy and Temperature-Programmed Pyrolysis Mass Spectrometry

Temperature-programmed pyrolysis mass spectrometry and Fourier-transform infrared spectroscopy have been used to monitor structural changes of humic and fulvic acids isolated from soils in China, in the temperature range of 25-550°C. in this work, we found that decarboxylation is obvious as the main reaction with dehydration reaction from 150°C to 400°C, the anhydride can be identified from FT-IR spectra at temperature range from 200°C to 400°C; there are evident changes of the aromatic nucleus of humic and fulvic acids above 400°C, even remaining up to 550°C. Besides, some changes of adsorption water can be distinguished before 200°C, and the mass signal of sulphur dioxide was detected.     

有机磷酸酯阻燃剂的环境暴露与迁移转化研究进展

有机磷酸酯(organophosphate esters,OPEs)是目前被广泛使用的阻燃剂添加成份,其具有神经、生殖、基因等生物毒性,且具有致癌性。作为新一类污染物,有机磷酸酯在环境中越来越多的释放引起了环境研究者的关注。文章综述了OPEs在水体、土壤、空气和生物体中的暴露浓度,并介绍了OPEs在环境中的各种迁移转化途径。目前针对OPEs的环境暴露研究仍十分有限,需要更全面调查其在多环境介质中的暴露状况以综合评价其生态风险。OPEs的多种迁移途径已得到证实,但相关物理化学转化和生物转化机制研究尚不完整。最后对OPEs的进一步研究提出了展望,以期促进我国OPEs的生态风险研究。     

Microbial nitrogen transformation potential in surface run-off leachate from a tropical landfill

Ammonium is one of the major toxic compounds and a critical long-term pollutant in landfill leachate. Leachate from the Jatibarang landfill in Semarang, Indonesia, contains ammonium in concentrations ranging from 376 to 929 mg N L⁻¹. The objective of this study was to determine seasonal variation in the potential for organic nitrogen ammonification, aerobic nitrification, anaerobic nitrate reduction and anaerobic ammonium oxidation (anammox) at this landfilling site. Seasonal samples from leachate collection treatment ponds were used as an inoculum to feed synthetic media to determine potential rates of nitrogen transformations. Aerobic ammonium oxidation potential (<0.06 mg N L⁻¹ h⁻¹) was more than a hundred times lower than the anaerobic nitrogen transformation processes and organic nitrogen ammonification, which were of the same order of magnitude. Anaerobic nitrate oxidation did not proceed beyond nitrite; isolates grown with nitrate as electron acceptor did not degrade nitrite further. Effects of season were only observed for aerobic nitrification and anammox, and were relatively minor: rates were up to three times higher in the dry season. To completely remove the excess ammonium from the leachate, we propose a two-stage treatment system to be implemented. Aeration in the first leachate pond would strongly contribute to aerobic ammonium oxidation to nitrate by providing the currently missing oxygen in the anaerobic leachate and allowing for the growth of ammonium oxidisers. In the second pond the remaining ammonium and produced nitrate can be converted by a combination of nitrate reduction to nitrite and anammox. Such optimization of microbial nitrogen transformations can contribute to alleviating the ammonium discharge to surface water draining the landfill.     

中国典型滨海湿地转变为养殖塘对土壤细菌多样性及群落结构的影响

以我国黄河口碱蓬湿地、九龙江口桐花树湿地、东寨港木榄湿地为研究样地,借助高通量测序技术探究这3个典型滨海湿地转变为养殖塘前、后土壤细菌多样性及群落结构的变化.结果表明：①天然湿地转变为养殖塘后,土壤细菌群落多样性与丰富度均有所下降;②天然湿地转变为养殖塘未显著改变细菌门水平群落组成,湿地优势细菌门主要为变形菌门（Proteobacteria）、绿弯菌门（Chloroflexi）、拟杆菌门（Bacteroidetes）、酸杆菌门（Acidobacteria）、厚壁菌门（Firmicutes）;③天然湿地转变为养殖塘改变了土壤优势细菌属,九龙江口和东寨港湿地转变后,寡养单胞菌属（Stenotrophomonas）相对丰度均有所升高,东寨港湿地转变后土壤中假单胞菌属（Pseudomonas）相对丰度也有所增加,并新增了气单胞菌属（Aeromonas）;4环境因子对湿地土壤细菌相对丰度有显著影响,寡养单胞菌属（Stenotrophomonas）与含水量呈显著负相关（p<0.05）,与容重和pH呈显著正相关（p<0.01）;Sulfurimonas、Woeseia等细菌属与土壤容重呈显著负相关（p<0.01）.由此可见,湿地围垦养殖对土壤微环境产生了较大影响,养殖户在进行养殖作业时需格外注重生态环境的健康与可持续发展.     

Response of ecological storage and conservation to land use transformation: A case study of a mining town in China

Rapid land use transformation shaped by agriculture, industrialization and population urbanization has a great influence on ecological environment. Based on theory of ecosystem service functions, this study aims at revealing the response of ecological storage and conservation to each unit area of land use transformation. Taking Cishan Town, a mining town in China, as a case study, this paper estimates the “past-present-future” ecological storage impacted by the process, result and possibility of land use transformation. The local land use and industrial distribution show that the active areas of land use transformation are also the areas of concentration of human (industrial) activities. Ecological storage shows the different responses to land use ways. And then this study combines the ecological storage indices with the indices of ecosystem pattern and land condition into the“5A” framework (active state, active degree, active possibility, active balance and active condition) for grading ecological conservation, and then assigns all regions of Cishan Town into different grades through membership functions for complex mapping of ecological conservation. The research results show that the ecological conservation in Cishan goes toward two extreme grades (best grade and worst grade). Uneven and unbalanced land use transformation is the main cause of that. Hence, rational and timely reflection of impact of land use transformation on ecological storage and conservation can assist land use planners and local government in adjusting land use ways and balancing regional ecology and economy.     

指标规范值的灰色聚类用于大气环境质量评价

为减少传统的灰色聚类法用于空气质量评价时涉及到白化函数的设计工作量,在设定空气指标＂参照值＂和＂规范变换＂基础上,将同级标准规范值相近的指标归为一类,属于同一类的指标设计为相同的归化函数,简化了函数的计算。将指标规范后的聚类分析方法应用于大连市区空气质量评价,结果表明：该方法用于空气质量评价具有简单、方便和实用的特点。