溴酸钾氧化酚红催化光度法测定亚硝酸根

本文研究了在亚硝酸根催化下溴酸钾氧化酚红的褪色反应，根据亚硝酸根灵敏的催化作用，建立了一种测定痕量亚硝酸根的新方法。该方法在室温下进行，操作尤为方便。灵敏度为７．６０×１０－１０／ｍＬ亚硝酸根，线性范围为０．０８～１．６μｇＮＯ－２／２５ｍＬ，具有良好的选择性。用于测定几种环境水样中亚硝酸根含量，其相对标准偏差为４．３％～６．６％，水样加标回收率为９４．７％～９８．２％。     

流动注射－催化褪色光度法测定痕量亚硝酸根的研究

依据亚硝酸根对溴酸钾氧化罗丹明Ｂ褪色反应体系的催化作用,建立了测定痕量亚硝酸根的停流－催化褪色光度法,确定了最佳测定条件：［ＫＢｒＯ３］＝５.０×１０－２ｍｏｌ·Ｌ－１,（罗丹明Ｂ］＝４.８×１０－５ｍｏｌ·Ｌ－１,［Ｈ２ＳＯ４］＝０.７５ｍｏｌ·Ｌ－１,５０℃。线性测定范围为０—０.６μｇ·ｍ１－１,方法检出限为２ｎ８·ｍ１－１。本法操作方便、快速、重现性好,且选择性较一般催化光度法显著提高。测定了不同样品中的亚硝酸根含量,结果满意。加标回收率为９６.１％－１０３.０％,相对标准偏差ＲＳＤ（ｎ＝６）为２.１％－４.０％。     

环境样品中亚硝酸盐及硝酸盐的催化光度测定研究

在１ｍｏｌ／Ｌ高氯酸溶液中，氯酸钠可将有机染料劳氏紫的兰色溶液缓慢氧化使其褪色．痕量的亚硝酸盐存在下此反应被大大加速。据此建立了催化光度测定亚硝酸根的新方法，该法测定ＮＯ线性范围可达３×１０－９～５×１０－６ｍｏｌ／Ｌ，５次测定的相对标准偏差为５％，大量的硝酸根存在不于抗测定．结合样品处理技术，可同时测定环境样品中硝酸盐及亚硝酸盐总量及分量．实际分析样品的结果满意．     

原子吸收法间接测定水中微量钛

用三正辛基膦化氧（ＴＯＰＯ）－环乙烷萃取钛，使用Ｔ型毛细管－根喷雾有机相，另一根喷雾４０ｍｇ／ＬＣａ溶液，用Ｃａ灯通过测量干扰元素被对干扰元素测定的影响对Ｔｉ进行间接测定，方法最佳线性范围０．５～３．０ｍｇ／Ｌ，加收率９０％～１０２％之间，相结标准偏差为２．８％～３．８％。     

Ni/Fe/Cu氧化物的催化臭氧化作用研究

以吐氏酸的臭氧氧化为例,研究了过渡金属镍、铁、铜单组分和不同配比双组分氧化物的催化作用,附着沉淀法制备的Ｎｉ－Ｆｅ（１：４）和Ｎｉ－Ｃｕ（４：１）催化剂的臭氧利用率分别比γ－Ａｌ２Ｏ３载体提高了２８．９％和２４．３％,金属氧化催化臭氧化能显著改善吐氏酸溶液的可生化性,当溴氧消耗量为０．２５－０．３５ｇ／Ｌ时,ＢＯＤ５／ＣＯＤ达到最大值０．２８。     

大气及公共场所中甲醛的测定

本文采用４－氨基－３－联氨－５－巯基－１，２，４－三氮杂茂（简称ＡＨＭＴ）。并以偏重亚硫酸钠作吸收液，使其生成羟基甲磷酸以固定甲醛．其吸收效率达９５％以上。回收率范围为９３．１～１０３．５％。三种不同浓度甲醛重复测定的平均相对标准差为２．９％。其测定范围为１０～１６０μｇ／ｍ３。大气中的ＳＯ_２和ＮＯ_２等不干扰测定。     

饮用水中NO3去除

研究了粒状滤床生化反应柱对ＮＯ３去除特性，结果表明，当容积负荷范围为每日１．９２－３．８ｋｇ（ＮＯ３－Ｎ）／ｍ＾３时，反硝化率为９５．７－１００％，相应ＣＨ３ＯＨ消耗量为每日４．９－９．８ｋｇ／ｍ＾２，ＣＯＤＣｒ去除负荷为每日７．３－１４．６ｋｇ／ｍ＾３。进水ＮＯ３浓度越征，达到完全反硝化所需的Ｃ／Ｎ值越高，投加的Ｃ／Ｎ值越高，实际消耗的Ｃ／Ｎ值越高，当投加的Ｃ／Ｎ值低时，其消耗的Ｃ／Ｎ值也低，越     

阳极溶出伏安法测定水体中痕量Sb^5＋

在ｐＨ３．４，８－羟基喹啉、甲基橙的浓度分别为４３μｍｏｇ／Ｌ、１３μｍｏｌ／Ｌ的０．１ｍｏｌ／Ｌ（ＮＨ４）２ＳＯ４底液中，用阳极溶出伏安法直接测定水体中Ｓｂ＾５＋。其线性范围为０．２６～５．２ｎｍｏｌ／Ｌ，方法的检出限为０．１ｎｍｏｌ／Ｌ；９次重复测定的变异系数为０．８％；回收率为９５．６％～１０４％。大部分常见阳离子不干扰测定。     

株洲市工业区大气中SO2转化速率的研究

在湖南省株洲市工业区的下风向布点,同时测定大气中ＳＯ２的浓度、ＴＳＰ和＜０．２５μｍ细粒子中ＳＯ２－４的浓度．结果表明,大气中ＳＯ２浓度随着离污染源距离的增加迅速下降,和ＳＯ２相比,颗粒物中ＳＯ２－４浓度随距离的增加而降低的程度要慢得多．同步测定的ＳＯ２浓度和细粒子ＳＯ２－４浓度有显著的相关关系．根据风向、风速和新产生的细粒子中的ＳＯ２－４浓度及大气中ＳＯ２的浓度计算了株洲教育学院处ＳＯ２的转化速率,春季湿度大,ＳＯ２转化速率也大,为４．８％／ｈ,秋季湿度小,ＳＯ２的转化速率变低,为１．５％／ｈ．春季中路铺ＳＯ２转化速率为３．１％／ｈ．     

亚硝酸根—番红O重氮化偶联反应机理研究

研究了在酸性介质中，亚硝酸根离子与番红Ｏ偶联反应的机理，并作为光度分析新方法应用于测定亚硝酸根离子，研究表明，在５２０ｎｍ处，试剂空白同试液吸光度的差值与亚硝酸根离子的含量在２０－５００μｇ／Ｌ范围内的成线性关系。方法用于土壤，环境水样中亚硝酸根离子的测定，结果满意。     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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