缓释型化学氧化剂在地下水DNAPLs污染修复中的应用研究进展

重质非水相有机污染物具有高密度、高毒性、低水溶性和高界面张力的特性,在自然条件下难以降解.缓释型化学氧化剂可以控制反应性化合物的释放,减少氧化剂的非选择性消耗,在地下水低渗透含水层DNAPLs(重非水相液体,dense nonaqueous-phase liquids)污染修复中有巨大的发展潜力.本文通过大量的文献调研,综述了缓释型化学氧化剂的制备方法及其在DNAPLs污染修复中的应用,梳理和总结了高锰酸盐、碱土金属过氧化物、过硫酸盐3类代表性缓释氧化剂的制备方法及其在修复低渗透含水层重非水相有机污染的应用研究现状,并对未来研究提出了建议.     

Particulate matter pollution and emergency room visits for respiratory diseases in a valley Basin city of Northwest China

Environmental Geochemistry and Health - Epidemiological studies have suggested that particulate matter (PM) pollution seriously affects human health, particularly it is closely associated with...     

离子选择性微电极用于外界胁迫下细胞液中钙分布检测的新模式

离子选择性微电极(ISME)是一种电化学传感器。在单细胞检测中可用来测定细胞内各种离子的浓度和胞外空间的离子流。本文提出了一种离子选择性微电极用于单细胞检测的新方法,即用离子选择性微电极测量植物细胞原生质体破裂时形成的离子浓度脉冲信号,进而分析细胞液中离子浓度的分布。并用此方法研究了在低温、纳米氧化铜(CuO NPs)、重金属(铽、镉)和乙醇等不同因素作用下,芦荟(Aloe vera)细胞原生质体的细胞液中Ca~(2+)的浓度分布。实验结果表明,在冷冻、CuO NPs、硝酸铽和氯化镉处理后细胞液中的Ca~(2+)浓度分布发生分层现象,而乙醇处理则不会出现这种现象。这种方法具有抗干扰能力强和操作简便的优点,为更全面地揭示细胞对外界刺激的响应特征提供了新的视角,也可为各种环境和生态毒理学评价提供新的途径。     

人工纳米材料在水-生物膜体系中的环境行为与毒性效应研究进展

随着纳米技术的飞速发展,人工纳米材料随人类活动以及纳米产品进入水-生物膜体系的环境行为以及毒性效应受到越来越多的关注。概述了纳米材料释放到水体后可能发生的环境行为及机理,阐述了纳米颗粒对生物膜中细菌活性的毒性作用,并揭示了生物膜抵抗纳米毒性的机制,为深入研究纳米颗粒在水体中的环境行为及生态效应提供重要的理论依据。     

双肢剪力墙考虑剪切变形和转动惯量时的自振周期

剪力墙结构在水平振动时的自振周期是确定地震作用时首要的动力特性参数.以双肢剪力墙为例,按是否考虑剪切变形和转动惯量的影响分成两种方法,根据结构自由振动微分方程及其自振周期公式,计算比较了不同墙肢宽高比下两种方法的计算结果,分析了剪切变形和转动惯量对结构自振周期的影响.计算结果表明:考虑剪切变形和转动惯量时,双肢剪力墙结...     

不同组合方式水培植物净化室内甲醛效果的差异

为研究植物根系分离与植物根系不分离2种方式水培植物组合净化室内甲醛效果,确定能够最大限度地发挥水培植物组合净化甲醛的科学栽培方式,并为设计和制造水培植物组合栽培容器与设备提供有效指导,该文以6种常见水培植物:尖尾芋(Spathiphyllum floribundum)、鹅掌柴(Schefflera octophylla)、鸟巢蕨(Neottopteris nidus)、绿萝(Epipremnum aureum)、绿精灵合果芋(Syngonium podophyllum‘Pixie’)、狼尾蕨(Davallia bullata)为试验材料,采取真实房间污染模拟,根据试验房间甲醛浓度变化与植物逆境生理指标分析植物甲醛吸收能力与耐受能力的差异。研究发现,水培植物组合吸收甲醛能力排序为植物根系分离实验组>植物根系不分离实验组>水对照组。隶属函数分析法表明,植物根系分离水培植物组合方式能够增强植物甲醛耐受能力。植物根系分离的水培植物栽培组合方式能够更好地发挥水培植物净化甲醛效果。     

Nitrogen and phosphorus removal comparison between periphyton on artificial substrates and plant-periphyton complex in floating treatment wetlands

Environmental Science and Pollution Research - Artificial substrates (ASs) and floating treatment wetlands (FTWs) have been widely used in the treatment of polluted surface water. In fact,...     

聚合多巴胺功能化非织造布增强Fe2+活化过硫酸盐降解酸性红B

为了提高Fe²⁺活化过硫酸盐(PS)过程中Fe²⁺的利用效率,降低其对自由基的淬灭作用.制备了聚多巴胺复合聚丙烯非织造布(PDA-PP),考察了PDA-PP材料应用于Fe²⁺/PS体系中,对酸性红B(ARB)的氧化降解性能和机理.结果表明：PDA-PP/Fe²⁺/PS体系能够更持续地活化PS氧化降解ARB.一方面聚多巴胺中酚羟基使Fe³⁺还原为Fe²⁺,保持对PS分解的持续性,另一方面聚多巴胺中的邻苯二酚和氨基对Fe²⁺的络合作用控制了Fe²⁺的释放速率,降低了Fe²⁺对自由基的淬灭.自由基淬灭实验与ESR分析结果表明,羟基自由基(·OH)是PDA-PP/Fe²⁺/PS体系的主要活性物种.(SO₄^·-)的产生量少于·OH.研究显示,PDA-PP的加入能有效提高Fe²⁺/PS体系中Fe²⁺     

Quantifying the sensitivity of ephemeral streams to land disturbance activities in arid ecosystems at the watershed scale

Large areas of public lands administered by the Bureau of Land Management and located in arid regions of the southwestern United States are being considered for the development of utility-scale solar energy facilities. Land-disturbing activities in these desert, alluvium-filled valleys have the potential to adversely affect the hydrologic and ecologic functions of ephemeral streams. Regulation and management of ephemeral streams typically falls under a spectrum of federal, state, and local programs, but scientifically based guidelines for protecting ephemeral streams with respect to land-development activities are largely nonexistent. This study developed an assessment approach for quantifying the sensitivity to land disturbance of ephemeral stream reaches located in proposed solar energy zones (SEZs). The ephemeral stream assessment approach used publicly-available geospatial data on hydrology, topography, surficial geology, and soil characteristics, as well as high-resolution aerial imagery. These datasets were used to inform a professional judgment-based score index of potential land disturbance impacts on selected critical functions of ephemeral streams, including flow and sediment conveyance, ecological habitat value, and groundwater recharge. The total sensitivity scores (sum of scores for the critical stream functions of flow and sediment conveyance, ecological habitats, and groundwater recharge) were used to identify highly sensitive stream reaches to inform decisions on developable areas in SEZs. Total sensitivity scores typically reflected the scores of the individual stream functions; some exceptions pertain to groundwater recharge and ecological habitats. The primary limitations of this assessment approach were the lack of high-resolution identification of ephemeral stream channels in the existing National Hydrography Dataset, and the lack of mechanistic processes describing potential impacts on ephemeral stream functions at the watershed scale. The primary strength of this assessment approach is that it allows watershed-scale planning for low-impact development in arid ecosystems; the qualitative scoring of potential impacts can also be adjusted to accommodate new geospatial data, and to allow for expert and stakeholder input into decisions regarding the identification and potential avoidance of highly sensitive stream reaches.