Photocatalytic degradation of phenanthrene on soil surfaces in the presence of nanometer anatase TiO2 under UV-light

The effect of nanometer anatase TiO₂ was investigated on the photocatalytic degradation of phenanthrene on soil surfaces under a variety of conditions. After being spiked with phenanthrene, soil samples loaded with different amounts of TiO₂ (0 wt.%, 1 wt.%, 2 wt.%, 3 wt.%, and 4 wt.%) were exposed to UV-light irradiation for 25 hr. The results indicated that the photocatalytic degradation of phenanthrene followed the pseudo first-order kinetics. TiO₂ significantly accelerated the degradation of phenanthrene with the half-life reduced from 45.90 to 31.36 hr for TiO₂ loading of 0 wt.% and 4 wt.%, respectively. In addition, the effects of H₂O₂, light intensity and humic acid on the degradation of phenanthrene were investigated. The degradation of phenanthrene increased with the concentration of H₂O₂, light intensity and the concentration of humic acids. It has been demonstrated that the photocatalytic method in the presence of nanometer anatase TiO₂ was a very promising technology for the treatments of soil polluted with organic substances in the future.     

日本应急管理法律体系的六大特点

<正>日本地处欧亚板块、菲律宾板块、太平洋板块交接处,处于太平洋环火山带,台风、地震、海啸、暴雨等各种灾害极为常见,是世界上易于遭受自然灾害的国家之一。在长期与灾难的斗     

粘土渗透仪的改进与探讨

改进后的粘土渗透仪,采用了直接击实法测定粘土渗透系数,可防止渗透实验中易出现的侧渗现象,减少实验误差,实验中用气体加压,可使粘土渗透系数的测定周期从1～2个月缩短至2～3 d。实测数据与常规标准渗透仪数据可比。并可进行有害物质渗滤液在粘土中渗透速度、转化、吸附、交换等方面的实验研究,使用方便。      

生物稳定塘常规运行状态模拟与分析

利用在系统实验基础上建立的生态学模型对生物稳定塘的常规运行状态进行了模拟和计算,得到以下主要结论:多级塘各塘中的有机碳、无机氮及溶解性总磷浓度均随进水浓度的升高而增大,因而使用多级塘仍须严格控制进水水质;生物稳定塘系统有较高的去除有机氮的能力,但去除总氮的能力有限,出水中无机氮浓度仍较高;藻类含碳、氮、磷对进水浓度变化的响应规律一致,存在一个使藻类生长最佳的营养物浓度,本模拟中该浓度为进水C_(oi)=72.00mg/L,TN_i=23.80mg/L,TP_i=2.46mg/L,藻类浓度的提高有利于溶解性营养物质的去除;菌含碳、氮、磷对进水浓度变化的响应规律服从Monod方程。     

一种海生黄藻的氨基酸和脂肪酸组成

对一种海生超微型藻类,品系ＰＰ９８３,的分类学地位、生长和生化组成进行了研究．形态学观察和色素分析表明,ＰＰ９８３ 是一种黄藻．在２５ ℃和１００ μｍｏｌ ｍ － ２ ｓ－１ 的条件下,ＰＰ９８３ 的生长速率为１．１５ ｄｉｖｄ,其对数生长期的蛋白质、脂肪和糖类质量分数分别为干重的４０ ．２％ 、２５ ．０ ％ 和１１ ．１％ ;共检出了１７ 种氨基酸,其总量为干重的２７．８ ％ ．ＰＰ９８３ 的多不饱和脂肪酸（ＰＵＦＡｓ）占总可提取脂肪酸的２６．４％ ,其中主要是ＥＰＡ,占干重的４．６％ ,而ＤＨＡ未检出．结果显示,ＰＰ９８３ 不仅可作为海生动物的优良饵料,而且是ＥＰＡ的重要潜在资源     

对苯二酚生产中含硫酸锰废水的综合利用

根据硫酸锰废水的特性,采用中和除铁和硫化除钴、镍等方法先使废水净化,得到合格电解液.其后对该电解液通电并加入硒电解24小时,再经钝化等处理制得金属锰.利用电解硫酸锰后的阳极废水制取碳酸锰,并从碳酸锰废水中回收硫酸铵.本工艺简单可行,产品金属锰纯度达99.8％以上,经济和环境效益显著.     

水路十八弯

人处在一种什么样的情况下,会突然从心里蹦出来一个上帝?会格外思念亲人?在三峡腹地柴埠溪开漂,整整等了五天。去的时候,天空干干净净的,除了各种各样的鸟带着五彩缤纷的     

糖类在城市污水生物处理系统中的去除机理

研究了厌氧、缺氧和好氧状态下淀粉在城市污水生物处理系统中水相和泥相中吸附和降解的动力学参数,建立了淀粉在厌氧、缺氧、好氧状态下的降解动力学模型,并对模型预测的结果进行了验证.结果表明,Fritz-Schlunder模型可以较好地描述糖类在厌氧、缺氧和好氧污泥上的吸附过程,吸附的大分子糖类迅速水解为低一级的高分子物质和小分子物质;厌氧降解速率系数K厌、缺氧的降解速率系数K缺与好氧的降解速率常数的比值分别为0.40和0.64;所建立的动力学模型能较好的预测出水糖类的浓度(相对误差<10%).     

Habitat-quality effects on metapopulation dynamics in greater white-toothed shrews, Crocidura russula

The effects of patch size and isolation on metapopulation dynamics have received wide empirical support and theoretical formalization. By contrast, the effects of patch quality seem largely underinvestigated, partly due to technical difficulties in properly assessing quality. Here we combine habitat-quality modeling with four years of demographic monitoring in a metapopulation of greater white-toothed shrews (Crocidura russula) to investigate the role of patch quality on metapopulation processes. Together, local patch quality and connectivity significantly enhanced local population sizes and occupancy rates (R2 = 14% and 19%, respectively). Accounting for the quality of patches connected to the focal one and acting as potential sources improved slightly the model explanatory power for local population sizes, pointing to significant source-sink dynamics. Local habitat quality, in interaction with connectivity, also increased colonization rate (R2 = 28%), suggesting the ability of immigrants to target high-quality patches. Overall, patterns were best explained when assuming a mean dispersal distance of 800 m, a realistic value for the species under study. Our results thus provide evidence that patch quality, in interaction with connectivity, may affect major demographic processes.     

Relation of growth and condition with the <Emphasis Type="Italic">Pan</Emphasis> I locus in Atlantic cod (<Emphasis Type="Italic">Gadus morhua</Emphasis> L.) around Iceland

Growth and condition (both somatic and hepatosomatic index) of Atlantic cod spawning at different locations around Iceland was studied in relation to the Pan I locus. South of Iceland cod carrying the Pan I^AB and Pan I^BB genotypes were more frequent while cod carrying the Pan I^AA genotype was more frequent north of Iceland. Differences in growth were detected between cod spawning at different areas around Iceland. Cod spawning south of Iceland grew faster than cod spawning north of Iceland. Differences in growth rate were also observed among cod carrying different Pan I genotypes within a spawning area. The least frequent Pan I genotype expressed the highest growth in both south and north of Iceland. Cod carrying the Pan I^AA grew fastest at spawning locations south of Iceland, while cod carrying the Pan I^BB genotype grew fastest in north of Iceland. A consistent relationship between condition and the different Pan I genotypes was also observed in all the areas. Cod carrying the Pan I^AA expressed the highest somatic condition and the lowest hepatosomatic index. Together, these results indicate that the relation of growth and condition with the Pan I locus is more complicated than earlier thought and is likely to be influenced by other factors, like size-selective fishing and food supply.