纳米TiO_2光催化降解水溶性染料溶液的研究

研究了纳米ＴｉＯ２光催化剂对活性黄Ｘ６Ｇ、活性红Ｘ３Ｂ、活性蓝ＸＢＲ、碱性绿、碱性紫５ＢＮ、碱性品红等６种染料溶液的光解脱色效果。结果表明，在ｐＨ２的酸性溶液中，对浓度为６０ｍｇ／Ｌ的６种染料溶液的脱色率均超过９３．３％；即使对浓度达２００ｍｇ／Ｌ的活性蓝溶液，其脱色率仍可达７８．８％。染料溶液的ｐＨ值对纳米ＴｉＯ２光催化脱色效果影响较大     

单甲脒在土壤中的降解及持久性研究

本文对四种不同类型土壤中单甲脒及其盐酸盐在厌氧与好氧条件下的降解动态及其残留进行了研究。结果表明单甲脒及其盐酸盐均属不稳定的化合物，单甲脒在土壤中的半衰期为４．６－９．１ｄ，其盐酸盐的半衰期为２．０－６．２ｄ。结果还表明单甲脒盐酸盐在厌氧条件下较在好氧条件下降解缓慢；在厌氧条件时，土壤的ｐＨ值对其降解影响较大。在相同条件下，单甲脒比它的盐酸盐酸盐降解慢，其降解速率与土壤ｐＨ值无关。     

纳米TiO2光催化降解水溶性染料溶液的研究

研究了纳米ＴｉＯ２光催化剂对活性黄Ｘ６Ｇ,活性红Ｘ３Ｂ,活性蓝ＸＢＲ,碱性绿,碱性紫５ＢＮ,碱性品红等６种染料溶液的光解脱色效果。结果表明,在ｐＨ２的酸性溶液中,对浓度为６０ｍｇ／Ｌ的６种染料溶液的脱色率均超过９３．３％;即使对浓度达２００ｍｇ／Ｌ的活性蓝溶液,其脱色率仍可达７８．８％。染料溶液的ｐＨ值对纳米ＴｉＯ２光催化脱色效果影响较大。     

二氧化氯对水中病毒,藻类和浮游动物的失活效果

本文研究了二氧化氯对水中一些主要病毒，藻类和浮游动物的失活效果，以及不同消毒剂投量，接触时间和ｐＨ值等条件下，二氧化氯对水体中一些微生物的杀灭和失活效果。与流氯对比的结果表明：ＣｌＯ２对藻类失活效果优于或相当于液氯；ＣｌＯ２对病毒和浮游动物的失活效果显著优于液氯；ＣｌＯ２可在一广泛的ｐＨ值范围内杀灭微生物。     

乐安江重金属污染对浮游植物群落结构的影响

１９９３年和１９９４年对乐安江６个采样站浮游植物的两次调查结果表明，藻类的群落结构因不同河段水质状况不同而不同：未受矿山废水污染的上游海口站，藻类多样性指数较高，密度较低，优势种多为清洁神和耐中污的种类，水质较好；接纳大量矿山及采矿化工废水和生活污水的沽口站，藻类受到明显抑制，多样性指数极低，耐污种占绝对优势，水质极差；随流程和净化时间的延长，下游各站藻类的种类、数量、多样性指数、种类数比均不断上升，优势比不断下降，体现出明显的水质净化趋势．乐安江水体Ｃｕ２＋浓度与藻类的种类、数量、种类多样性指数、种类数比呈负相关的关系，Ｃｕ２＋浓度与藻类的优势比呈正相关关系；ｐＨ值与上述指标关系正好与Ｃｕ２＋所呈现的关系相反．藻类群落结构在春季丰水期与秋季枯水期的变化表明，春季乐安江水质好于秋季．     

重金属和油处理剂对水稻根系的影响

试验了Ｎｉ、Ｚｎ、Ｍｎ、Ｓｎ、Ｃｒ和Ｃｕ等６种重金属及油处理剂对水稻根系的影响，结果表明．水中含Ｎｉ０．００７ｍｇ／１、Ｃｕ０．００５ｍｇ／１时，能阻碍根系的伸长；含Ｚｎ０．５ｍｇ／１以上时。不利于根系的伸长；水中含Ｍｎ２０ｍｇ／１，Ｓｎ、Ｃｒ￣（６－）各５ｍｇ／１时，对根系有明显危害；水中含Ｃｒ￣（２＋）＋Ｃｒ￣（６＋）时，当１种离子浓度保持不变，根系的抑制程度随着另１种离子浓度的增加而增大。水中含油处理剂１０００ｍｇ／１时，能抑制水稻发根。     

吡虫啉的光解水解和土壤降

在实验室测定了吡虫啉的光解、不同ｐＨ条件下的水解与在东北黑土等３种不同土壤中的降解。试验结果表明，在３００Ｗ低压汞灯下，吡虫啉水相溶液的光解呈一级反应动力学反应，光解半衰期为６．８１ｈ；在ｐＨ５、ｐＨ７、ｐＨ９的缓冲溶液中的水解半衰期分别为３０．６、１３．６与８．０ｄ；在东北黑土、太湖水稻土和江西红壤中的降解半衰期分别为１０．７、１１．１和４．１ｄ。     

溴氟菊酯的光解,水解与土壤降解

在实验室测定了溴氟菊酯的光解、不同ｐＨ条件下的水解以及在太湖水稻土、江西红壤与东北黑土等３种不同土壤中的降解。试验结果表明：在３００Ｗ低压汞灯下，溴氟菊酯的水相溶液与其石油醚相溶液中的光解均呈二级反应动力学方程，光解半衰期分别为１３．７与９．４ｍｉｎ；在ｐＨ为５，７，９的缓冲溶液中其水解半衰期分别为１５．６，８．３与４．２ｄ；在３种不同土壤中的降解半衰期为４．８￣８．８ｄ。     

2,4,6—三氯酚在模型水生生态系统中的归宿

测定了模型水生生态系统水、底泥中２，４，６－三氯酚（ＴＣＰ）浓度随时间的变化值，以及ＴＣＰ从水中挥发、光解、底泥吸附、解吸、微生物降解的速率常数。假设水中ＴＣＰ的迁移和转化遵循一级速率过程，水中物质平衡能通过数学等式来描述，显示出室系统数学模型能粗略预测模型水生生态系统中ＴＣＰ浓度随时间的变化。最后，应用该模型预测了排放到天津室外兼性塘中ＴＣＰ的迁移、归宿，发现１５ｄ后出口水中ＴＣＰ浓度已降低到入     

大鼠全身曝露N,N-二甲基甲酰胺蒸汽后血液中N-甲基氨基甲酸硫酯动态研究

报道了经恒定气相浓度Ｎ，Ｎ－二甲基甲酰胺（ＤＭＦ）蒸汽曝露的雄性ＳＤ大鼠血液中以Ｓ－（Ｎ－甲基氨基甲酰）谷胱甘肽（ＳＭＧ）为代表的Ｎ－甲基氨基甲酸硫酯的代谢生成及体内消长．实验所用封闭曝露系统内ＤＭＦ蒸汽恒定浓度分别为φ＝２４×１０－６（直至４８ｈ）；φ＝８４×１０－６及φ＝２１３×１０－６（均为７２ｈ）．经（φ＝２４×１０－６）×２４ｈ处理后，大鼠血清中Ｎ－甲基氨基甲酸硫酯达到稳态浓度４７μｍｏｌ／Ｌ，当ＤＭＦ稳态蒸汽浓度φ＝８４×１０－６时，体内血清Ｎ－甲基氨基甲酸硫酯稳态浓度为２２７μｍｏｌ／Ｌ，在环境蒸汽浓度φ＜８４×１０－６时，大鼠体内Ｎ－甲基氨基甲酸硫酯稳态浓度与环境中ＤＭＦ蒸汽浓度呈线性关系．所产生的Ｎ－甲基氨基甲酸硫酯类物质体内半衰期在２．２～２．８ｈ之间，体内半衰期值主要是由其生成速率决定的．高浓度ＤＭＦ（φ＝２１３×１０－６）的曝露并未导致体内产生可检出水平的Ｎ－甲基氨基甲酸硫酯类物质，这可能是由于体内高浓度的ＤＭＦ对其本身代谢的抑制作用所致．     

生淀粉糖化酶产生菌Aspergillus niger(6#)的分离筛选及其产酶条件

从大曲中分离到了1株降解生淀粉能力较强的黑曲霉Aspergillusniger(6#).固体发酵酶活可达2461U/g,RDA值为21.47%;液体发酵酶活可达353U/mL,RDA值为20.30%.以6#菌为实验材料,进一步考察了氮源、碳源及pH对生淀粉糖化酶形成的影响.实验结果表明,无机氮源NaNO3较有机氮源蛋白胨更有利于生淀粉糖化酶的形成;pH是影响生淀粉糖化酶形成的重要因素,低pH会阻遏生淀粉糖化酶的形成;玉米粉和麦芽糖较其它碳源更有利于生淀粉糖化酶的形成.图4表2参12     

The effect of limestone treatments on the rate of acid generation from pyritic mine gangue

Surface water enters the Haile Gold Mine, Lancaster County, South Carolina by means of a small stream and is ponded behind a dam and in an abandoned pit. This water is affected by acidic drainage. In spite of the large exposures of potentially acid producing pyritic rock, the flux of acid to the water is relatively low. Nevertheless, the resulting pH values of the mine water are low (around 3.5) due to negligible buffering capacity. In view of the observed low release of acidity, the potential for acid drainage abatement by limestone ameliorants appears feasible. This study investigated the effects of limestone treatment on acid generation rates of the Haile mine pyritic rocks through a series of leaching experiments. Below a critical alkalinity threshold value, solutions of dissolved limestone were found consistently to accelerate the rate of pyrite oxidation by varying degrees. The oxidation rates were further accelerated by admixing solid limestone with the pyritic rock. However, after a period of about a month, the pyrite oxidation rate of the admixed samples declined to a level lower than that of untreated pyrite. Leachates produced by the pyrite and limestone mixtures contained little if any iron. Further, in the mixtures, an alteration of the pyrite surface was apparent. The observed behaviour of the treated pyrite appears to be related to the immersion of the pyrite grains within a high alkalinity/high pH environment. The high pH increases the rate of oxidation of ferrous iron which results in a higher concentration of ferric iron at the pyrite surface. This, in turn, increases the rate of pyrite oxidation. Above a threshold alkalinity value, the precipitation of hydrous iron oxides at the pyrite surface eventually outpaces acid generation and coats the pyrite surface, retarding the rate of pyrite oxidation.     

西安市南郊春季降水化学成分特征

2010年3-4月间采集了7次西安南郊降水样品,测定电导率、pH值、主要离子浓度.结果表明,降水pH值的平均值为6.6;电导率平均为110.5 μs/cm,说明降水中水溶性离子浓度高.Ca2+为含茸最丰富的阳离子,平均浓度为15.3 mg/L.由于北方春季沙尘天气频繁,空气中固体颗粒较多,所以降水中Ca2+浓度较高.同...     

天津市地表水体与沉积物中7种高关注酚类化合物的污染特征与生态风险分析

为探究地表水体与沉积物中酚类化合物的污染分布特征和生态风险,选择天津市3个水源地与6条主要河流,采集了26个地表水样与6个沉积物样品,利用固相萃取与超声萃取、高效液相色谱-串联质谱法(HPLC-MS/MS)测定了水样及沉积物中1-萘酚(1-naphthol)、壬基酚(nonylphenol, NP)、双酚A(bisphenol A, BPA)、2-苯基苯酚(biphenyl-2-ol)、3,4-二氯酚(3,4-dichlorophenol)、四溴双酚A(tetrabromobisphenol A, TBBPA)和对叔丁基苯酚(p-tert-butylphenol, PTBP)等7种高关注酚类化合物的浓度水平,并应用物种敏感性分布(species sensitivity distribution, SSD)法和熵值法(ecological risk quotient, RQ)评估7种酚类化合物水环境和沉积物的生态风险。结果表明,地表水样中7种酚类化合物均全部检出;其中壬基酚的检出浓度最高,其次为四溴双酚A、对叔丁基苯酚、1-萘酚、2-苯基苯酚、3,4-二氯酚和双酚A。沉积物中酚类化合物的污染分布规律与水样相似,除双酚A外的目标物全部检出。其中,壬基酚浓度比其他物质浓度高2个数量级。风险评估结果显示,壬基酚对水环境与沉积物存在不可接受的风险;而四溴双酚A、对叔丁基苯酚、1-萘酚、2-苯基苯酚、3,4-二氯酚和双酚A则对环境具有较低风险或者存在一定的风险。     

Micro-analysis of nitrogen transport and conversion inside activated sludge flocs using microelectrodes

To investigate the nitrogen transport and conversion inside activated sludge flocs, micro-profiles of O₂, NH₄⁺, NO₂^–, NO₃^–, and pH were measured under different operating conditions. The flocs were obtained from a laboratory-scale sequencing batch reactor. Nitrification, as observed from interfacial ammonium and nitrate fluxes, was higher at pH 8.5, than at pH 6.5 and 7.5. At pH 8.5, heterotrophic bacteria used less oxygen than nitrifying bacteria, whereas at lower pH heterotrophic activity dominated. When the ratio of C to N was decreased from 20 to 10, the ammonium uptake increased. When dissolved oxygen (DO) concentration in the bulk liquid was decreased from 4 to 2 mg·L^-1, nitrification decreased, and only 25% of the DO influx into the flocs was used for nitrification. This study indicated that nitrifying bacteria became more competitive at a higher DO concentration, a higher pH value (approximately 8.5) and a lower C/N.     

Analysis of a two-layer cloud system with RAMS model and comparison to airborne observations

A three-dimensional numerical model (Regional Atmospheric Modeling System—-RAMS) was used to study the formation and evolution of water forms in a two-layer cloud structure observed during a field campaign over Brest (France). The model performance in regular operations, using conventional meteorological data as initial and lateral boundary conditions, was also examined. Remote sensing observations of the cloud system and in-situ aircraft data, selected during the campaign, were used to validate the model outputs. The model simulations showed that the lower cloud formation was characterized by high number concentration of pristine ice and snow, while the concentration of aggregates, graupel and hail were considerably lower. Hydrometeors in liquid phase appeared demonstrating high number concentration and water content on the top of this layer. The upper cloud layer consisted only of frozen water substances in lower amounts. The qualitative and quantitative comparison of the model-calculated meteorological and microphysical fields to the available observational data revealed that the model reflected fairly well the cloud structure (e.g., the spatio-temporal variability of the cloud parameters, the geometry of the cloud system). However, there were deviations as far as the model underestimating the ice water content (IWC) and number concentration (N_t) fields is concerned, especially at the atmospheric layer between 2.5 and 4 km of altitude. These deviations of the model simulated quantities from the measured ones may be attributed either to the performance of the model’s microphysics scheme, to instrument inaccuracies and to the local disturbance caused by the aircraft.     

珠江三角洲城市雨水的化学组成及其成因探讨

于2005—2007年间,基于降水过程监测分析了广州市和珠海市雨水的化学组成。结果表明,广州市雨水的pH值变化于3.32~7.03之间,平均值为4.35,众数约为4.15。珠海市雨水的pH值变化于3.38~6.49之间,平均值为4.51。雨水pH值随降水强度的减弱而降低,这决定于大气中水汽与酸性气体的接触时间。珠江三角洲城市雨水中所含主要离子依次是SO42-、NO3-、NH4＋、Ca2＋、Cl-。雨水的酸化与降水过程密切相关。降雨初期雨水比中后期雨水的pH值高,揭示降雨初期大气中的粉尘颗粒有效中和雨水的酸度。多天连续降水天气对大气尘埃的清洗作用明显,但是持续的SO2和NOx排放更容易使雨水酸化。滨海城市降水初期雨水的电导率上升较快（可以从小于1μS.cm-1上升到20~30μS.cm-1）,随着降水时间的延长雨水的电导率以较慢的速率上升。     

模拟酸雨下H+-Ca2+在红壤表面的动力学特征

研究模拟酸雨下H Ca2 在红壤表面的反应动力学吸附特征 ,结果表明 :Ca2 的吸附动力学能很好地用一级动力学方程、抛物线扩散方程和Elovich方程 (R2 >0 97)拟合 .随溶液酸度的增加 ,Ca2 的最大吸附量显著降低 ,Ca2 吸附反应速率控制步骤是离子在颗粒内的扩散 ,扩散速率常数随酸度的增加而下降 .酸溶液pH值为 4 5和 5 6时 ,有H 的释放 ,H 的表观释放量能用一级动力学方程和扩散方程拟合 ,Elovich方程不宜拟合pH 5 6酸处理的动力学数据 ;酸溶液pH值为 3 5和 2 5时 ,有H 的消耗 ,H 消耗总量看作表观消耗量 ,用一级动力学方程、Elovich方程和扩散方程进行拟合 .比较相关系数和标准误差的大小 ,除pH值为 2 5的酸处理用扩散方程拟合结果较差外 ,这 3种动力学模型进行拟合均得到较满意的结果     

A novel ligand for cloud point extraction to determine gold content in ore samples

Gold is a valuable metal occurring usually at very low concentrations in complex natural samples. Gold analysis thus needs preconcentration methods. Classical liquid–liquid extraction involves hazardous organic solvents. Alternatively, cloud point extraction involves non-toxic and nonvolatile surfactants. Here, we analyzed ore samples. The complex of Au(III) with sulphapyridylazo resorcin was extracted by the cloud point method. Concentrations were measured by flame atomic absorption spectrometry. We tested the effects of pH, reagent concentration, Triton X-100 surfactant concentration, equilibration temperature and time. Results show that the best detection limit of the method was 0.48 µg L^?1 for Au with a preconcentration factor of 31 times. Calibration is linear in range of 6.4–2,000 µg L^?1, and relative standard deviations are lower than 5 %. Quantum chemical computations reveal the plausible structure of the gold–ligand complex. This report represents the first determination of gold using sulphapyridylazo resorcin as a ligand.     

固体聚硅硫酸铁混凝剂的表面形貌及混凝效能

以水玻璃、硫酸亚铁及氯酸钠为原料,采用共聚法制备不同Si/Fe摩尔比的聚硅硫酸铁(PFSS)混凝剂,通过两种方式固化:(1)将未稀释的PFSS经自然干燥制成凝胶状样品;(2)将不同聚合反应时间的PFSS稀释后干燥制成粉末状样品.用扫描电镜及X射线衍射仪对其表面形貌及成分进行观察和分析,对比粉末状固体PFSS与液体PFSS的混凝性能.结果表明,两种固化手段制备的PFSS表面形貌完全不同,其中凝胶状样品没有孔隙、连接紧密,而粉末状样品是松散的片状或晶须状结构,Si/Fe摩尔比对样品的表面形貌有很大影响.PFSS不是原料的简单复配,而是"硅铁反应的共聚物".反应时间对固体PFSS混凝性能的影响小于对液体PFSS的影响,制备液体和固体混凝剂需要不同的反应时间.与液体PFSS相比,固体PFSS的除浊性能随Si/Fe摩尔比的增加逐渐下降,而除UV254的性能却逐渐升高.延长沉淀时间有利于固体PFSS混凝性能的提高.