2种人工湿地的水力停留时间及净化效果

以复合垂直流人工湿地(IVCW)和水平潜流人工湿地(HSCW)为研究对象,研究了2种湿地运行的季节性最佳水力停留时间(HRT)参数,并监测了2种湿地在最佳HRT参数下运行时对污水的净化效果。结果显示:(1)在IVCW中,最佳HRT在春、秋季为8～10 h;夏季为6 h;冬季为12 h。在HSCW中,最佳HRT在春、秋季为10～12 h;夏季为6～8h;冬季为24～36 h。(2)2种湿地对COD的去除率均无显著的季节性差异;湿地进水中NH4+-N/TN比值与TN去除率显著负相关;不同季节下IVCW对TN的去除效果均高于HSCW。(3)水温对TN、TP去除率的影响在IVCW中比HSCW中的明显;水温高时,2种湿地中的TN去除率较高,IVCW中的TP去除率也较高,但HSCW中的TP去除率则较低,它们间均未达到显著的相关性。     

Volatilization behaviors of diesel oil from the soils

The volatilization of diesel oil, Shengli crude oil and 90 # gasoline on glass surface of petri dishes were conducted at the ambient temperature of 25℃. Diesel oil evaporates in a power manner, where the loss of mass is approximately power with time. 90 # gasoline evaporates in a logarithmic with time. Where as the volatilization of Shengli crude oil fit either the logarithmic or power equation after different time, and has similar R^2 . And the effects of soil type and diesel oil and water content on volatilization behavior in unsaturated soil were studied in this paper. Diesel oil and water content in the soils play a large role in volatilization from soils. Appropriate water helps the wicking action but too much water stops it. The wicking action behaves differently in four different types of soils in the same volatilization experiment of 18% diesel oil content and air-dry condition.     

公路滑坡灾害链式反应阶段性识别方法研究

为了对公路滑坡的发育阶段做出准确判别,研究了公路滑坡灾害发育的链式反应机理,将滑坡的发育阶段划分为3个阶段。采用广泛调研和专家咨询的技术手段,从发育阶段的表现特征中选定了滑坡识别的相关因素集和评分,在此基础上采用模糊数学的方法对公路滑坡灾害的发育阶段进行了识别,并在陕南公路滑坡调查中初步应用。     

生物炭对铅离子的吸附性能

以废弃松木屑为原料,采用控制热分解法制备了生物炭。运用BET和FTIR等技术对生物炭进行了表征,考察了生物炭对铅离子的吸附效果,并探讨了吸附机理。表征结果显示,700℃氨气处理的生物炭,其比表面积和总孔体积显著增大。实验结果表明:生物炭对铅离子的吸附效果优于普通活性炭,且以700℃氨气处理的生物炭为最佳;随溶液pH的升高生物炭对铅离子的去除率增大,当pH为4~6时去除效果较好;在溶液pH为6、初始铅离子质量浓度为50 mg/L、吸附剂加入量为1 g/L、吸附时间为6 h的条件下,700℃氨气处理的生物炭对铅离子的去除率达99%以上;700℃氨气处理的生物炭的Langmuir吸附常数和Freundlich吸附常数远大于普通活性炭和其他工艺的生物炭;铅离子在生物炭上的吸附过程符合拟二级动力学方程。     

改性啤酒酵母及柑橘皮凝胶小球对铜的吸附性能

为有效去除污水中的铜离子并实现资源有效的利用,以啤酒酵母和柑橘皮为原料制备海藻酸钙固定啤酒酵母菌小球(SCA)、海藻酸钙固定柑橘皮小球(OPCA)及海藻酸钙固定柑橘皮及啤酒酵母菌复合小球(OPSCA),研究了其对铜离子的吸附和解吸性能。研究结果表明,3种吸附剂对铜离子吸附的最佳pH值为5.0,吸附量的大小顺序为:OPSCAOPCASCA。吸附动力学数据符合准二级动力学模型。吸附过程被内扩散步骤和外扩散步骤共同控制。Langmuir等温吸附模型能较好地模拟3种吸附剂的吸附数据,SCA、OPCA及OPSCA的理论最大吸附量分别为33.49、40.80和61.69 mg/g。3种吸附剂可利用0.1 mol/L的盐酸解吸再生,可循环使用3次以上。     

Determining reference conditions for TN, TP, SD and Chl-a in eastern plain ecoregion lakes, China

Establishing the nutrient reference condition(baseline environmental condition) of lakes in an ecoregion is a critical consideration in the development of scientifically defensible aquatic nutrient criteria.Three methods were applied to determine reference conditions in the Eastern plain ecoregion lakes with respect to total phosphorus(TP),total nitrogen(TN),planktonic chlorophyll a(Chl-a) and Secchi depth(SD).The reference condition value for the lakes in the Eastern plain ecoregion by the trisection method is TP of 0.029 mg/L,TN of 0.67 mg/L,Chl-a of 3.92 mg/m 3,SD of 0.85 m,and the reference condition range by the lake population distribution approach is TP of 0.014-0.043 mg/L,TN of 0.360-0.785 mg/L,Chl-a of 1.78-4.73 mg/m 3,SD of 0.68-1.21 m.Additionally,empirical models were developed for estimating the reference Chl-a concentration and SD successfully for lakes in the Eastern plain ecoregion.Overall,the data suggest that multiple methods can be used to determine reference conditions and that in Eastern plain ecoregion lakes the reference condition corresponds to a mesotrophic status.     

Effects of two polybrominated diphenyl ethers (BDE-47, BDE-209) on the swimming behavior,population growth and reproduction of the rotifer Brachionus plicatilis

Polybrominated diphenyl ethers(PBDEs) are new kinds of persistent organic pollutants(POPs) and their potential threats to the equilibrium and sustainability of marine ecosystems have raised worldwide concerns. Here, two kinds of PBDEs, tetra-BDE(BDE-47)and deca-BDE(BDE-209) were applied, and their toxic effects on the swimming behavior,population growth and reproduction of Brachionus plicatilis were investigated. The results showed that:(1) The actual concentrations of BDE-47 and-209 in the seawater phase measured by GC–MS(Gas Chromatography-Mass Spectrometer) were much lower than their nominal concentrations.(2) In accordance with the 24-hr acute tests, BDE-209 did not show any obvious swimming inhibition to rotifers, but a good correlation did exist between the swimming inhibition rate and BDE-47 concentration suggesting that BDE-47 is more toxic than BDE-209.(3) Both BDE-47 and-209 had a significant influence on the population growth and reproduction parameters of B. plicatilis including the population growth rate, the ratio of ovigerous females/non-ovigerous females(OF/NOF), the ratio of mictic females/amictic females(MF/AF), resting egg production and the mictic rate, which indicate that these parameters in B. plicatilis population were suitable for monitoring and assessing PBDEs. Our results suggest that BDE-47 and-209 are not acute lethal toxicants and may pose a low risk to marine rotifers at environmental concentrations for short-term exposure. They also accumulate differently into rotifers. Further research data are needed to understand the mechanisms responsible for the effects caused by PBDEs and to assess their risks accurately.     

Novel synthetic approaches and TWC catalytic performance of flower-like Pt/CeO2

A novel Ultrasonic Assisted Membrane Reduction （UAMR）-hydrothermal method was used to prepare flower-like Pt/CeO2 catalysts. The texture, physical/chemical properties, and reducibility of the flower-like Pt/CeO2 catalysts were characterized by X-Ray Diffraction （XRD）, Scanning Electron Microscope （SEM）, Transmission Electron Microscope （TEM）, N2 adsorption, and hydrogen temperature programmed reduction （HE-TPR） techniques. The catalytic performance of the catalysts for treating automobile emission was studied relative to samples prepared by the conventional wetness impregnation method. The Pt/CeO2 catalysts fabricated by this novel method showed high specific surface area and metal dispersion, excellent three-way catalytic activity, and good thermal stability. The strong interaction between the Pt nanoparticles and CeO2 improved the thermal stability. The Ce4＋ ions were incorporated into the surfactant chains and the Pt nanoparticles were stabilized through an exchange reaction of the surface hydroxyl groups. The SEM results demonstrated that the Pt/CeO2 catalysts had a typical three-dimensional （3D） hierarchical porous struc- ture, which was favorable for surface reaction and enhanced the exposure degree of the Pt nanoparticles. In brief, the flower-like Pt/CeO2 catalysts prepared by UAMR-hydrothermal method exhibited a higher Pt metal dispersion, smaller particle size, better three-way catalytic activity, and improved thermal stability versus conven- tional materials.     

Estimation of the daily soil/dust (SD) ingestion rate of children from Gansu Province,China via hand-to-mouth contact using tracer elements

A total of 60 children (31 males and 29 females) between the ages of 3 and 12 years were randomly selected from Lanzhou City in Gansu Province, northwest China. Hand (soil/dust) SD samples from these children were collected using hand wipes. We determined the approximate amounts of hand SD and the concentrations of three tracer soil elements (Ce, Y, and V) in these samples. The approximate amounts of hand SD ranged from 42.28 to 173.76 mg, with a median value of 85.42 mg. In addition, the mean amounts of hand SD estimated using the concentrations of Ce, Y, and V in the samples were 4.63, 3.43, and 3.42 mg, respectively. The amount of hand SD varied greatly among the age groups: primary school children had more hand SD than kindergarten children, males had more hand SD than females, and children from rural areas had more hand SD than those from urban areas. The rates of daily ingestion of hand SD for kindergarten and primary school children were estimated to be 7.73 and 6.61 mg/day, respectively.     

Urban ecological security dynamic analysis based on an innovative emergy ecological footprint method

Environment, Development and Sustainability - In China, with the rapid development of economy and the advancement of urbanization, the deterioration of urban ecological environment is obvious. In...