Photolytic treatment of atrazine-contaminated water: products, kinetics, and reactor design.

This study investigates the products, kinetics, and reactor design of atrazine photolysis under 254-nm ultraviolet-C (UVC) irradiation. With an initial atrazine concentration of 60 microg/L (60 ppbm), only two products remain in detectable levels. Up to 77% of decomposed atrazine becomes hydroxyatrazine, the major product. Both atrazine and hydroxyatrazine photodecompose following the first-order rate equation, but the hydroxyatrazine photodecomposition rate is significantly slower than that of atrazine. For atrazine photodecomposition, the rate constant is proportional to the square of UVC output, but inversely proportional to the reactor volume. For a photochemical reactor design, a series of equations are proposed to calculate the needed UVC output power, water treatment capacity, and atrazine outlet concentration.     

Copper tolerance,uptake and accumulation by Phragmites australis

Copper (Cu) uptake and accumulation of five populations of Phragmites australis growing in two mine sites (Parys Mountain, Wales, UK and Plombières, Belgium) contaminated with Cu and three 'clean' sites (Felixstowe, UK; Wisbech, UK and Mai Po, Hong Kong) were studied under field and glasshouse conditions. Cu tolerances in these populations of seedlings raised from seeds collected from the above five sites were also studied under glasshouse conditions. Although concentrations of Cu in the plant tissues (leaves, stems, rhizomes and roots) of P. australis and the associated soils from the Cu-contaminated sites were significantly higher than those of the plant tissues and the soils collected in the clean sites, small differences were found between the two Cu-contaminated populations and the three clean populations when seedlings were grown in 0.1 and 0.5 microg ml(-1) Cu treatment solutions. In general, different populations of seedlings showed similar growth responses, metal uptake and indices of Cu tolerance when cultured in the same Cu treatment solution for 3 weeks. There was insufficient evidence to support the hypothesis that the Cu-contaminated populations have evolved to Cu-tolerant ecotypes.     

Enhanced uptake of As, Zn, and Cu by Vetiveria zizanioides and Zea mays using chelating agents

Vetiveria zizaniodes (vetiver) is commonly known for its effectiveness in soil and sediment erosion control. It can tolerate to extreme soil conditions and produce a high biomass even growing in contaminated areas. Zea mays (maize) can also produce a very high biomass with a fast growth rate and possesses some degree of metal tolerance. A greenhouse study was conducted to investigate the feasibility of using vetiver and maize for remediation of arsenic (As)-, zinc (Zn-), and copper (Cu)-amended soils and evaluate the effects of chelating agents on metal uptake by these plants. Vetiver had a better growth (dry weight yield of root and shoot) than maize under different treatment conditions. The effects of different chelating agents on As, Zn, and Cu extraction from soil to soil solution were studied. Among the nine chelating agents used, it was noted that 20 mmol NTA could maximize As and Zn bioavailability, while 20 mmol HEIDA could maximize Cu bioavailability in the soil solution. The surge time in maximizing metal uptake ranged from 16 to 20 days which indicated that timing on plant harvest was an important factor in enhanced metal accumulation. In general, vetiver was a more suitable plant species than maize in terms of phytoextraction of metals from metal-contaminated soil. Application of NTA in As-amended soil and HEIDA in Cu-amended soil at the rate of 20 mmol kg(-1) increased 3-4-fold of As and Cu in shoot of both plants, whereas application of NTA (20 mmol kg(-1)) increased 37- and 1.5-fold of Zn accumulation in shoot of vetiver and maize, respectively. The potential environmental risk of metal mobility caused by chelating agents used for phytoextraction should not be overlooked.     

绿色设计与绿色化学设计

根据绿色设计的基本定义，特点，过程与原则，将绿色设计与传统设计与进行比较，阐述绿色化学设计的主要内容。     

分光光度法同时测定水中邻苯二甲酸和邻苯二甲酸二甲酯

本文用双波长等吸收紫外分光光度法，同时测定水中邻苯二甲酸（ＰＡ）和邻苯二甲酸二酯（ＤＭＰ）的含量，实验表明，ＤＭＰ和ＰＡ在１ｍｇ／ｌ到５０ｍｇ／ｌ的浓度范围内，对于波长为２１６，２３７．６，２６６，２９２ｎｍ的吸收均满足比尔吸收定律，迭加性令人满足，分析方法的回收率在ＤＭＰ与ＰＡ含量比例相差较小时，其值接近１００％。在相差超过９倍时，通过合理的校正，回收率也能达到９０％－１１０％，回收率受Ｎａ＾＋     

新单塔污水汽提装置运行综述

介绍新增单塔污水汽提装置的必要性，对装置的工艺流程进行了说明，并在此基础上对该装置运行的工艺指标和产品质量控制指标对比分析，提出了存在的问题。     

工业废水中微量镍的流动注射光度分析

采用流动注射分析技术,在柠檬酸,碘存在的氨性介质中,以丁二酮肟为显色剂,应用光度自动分析方法,测定废水中微量镍,检出限为0.3mg·l~(-1);线性范围为0.3～10mg·l~(-1);相对标准偏差<1％。     

重庆市主要公共集会场所、交通道路和风景旅游区环境空气质量的研究

通过对满足选点标准的5个调查点和7个空气质量质控对照点，一年四个季度每季度抽样5d以上连续自动监测环境空气质量的科研性监测方式，共获取各类有效数据约20万个，从而以定量的方式确定了重庆市主要公共集会场所，交通道路和风景旅游区的环境空气质量水平。     

污水深度处理中3种过滤法的技术性能研究

以城市污水回用为目的，研究了污水深度处理中的过滤技术，结果陶瓷－石英砂双层滤料的滤柱，在滤速为５．２ｍ／ｈ时，通过直接过滤即可将污水处理厂二级出水中的悬浮物几乎全部去除，且过滤周期可达６１．２－７２．１ｈ。     

高层建筑承受纵向地震波时的安全核算构想

高层建筑可预期的灾变非至一端，这里仅探讨高层建筑的抗震性能问题。地震过程中楼体受到的是地震波和自身固有频率的共同作用，此时楼体是一个多维动态系统，其应力状态比传统方法所描述的力学模型要复杂行多。本文应用ANSYS三维仿真有限元软件，采用单点响应谱的方法，对楼体在纵向地震波作用下的应力状态和变形情况进行了分析。对楼体构件单元型式的选择、网格密度的确定、有限元模型的建立等也提出了自己的见解。在后处理中，用列表和图形的方式显示了楼体的位移和应用状态。