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81.
82.
太阳能在处理水、大气及土壤中有机污染物方面的应用 总被引:4,自引:0,他引:4
太阳能除作为传统的热源外,还可用于驱动化学过程。本文主要介绍利用光催化氧化技术处理废水、大气及土壤中有机污染物方面的最新进展,正在进行的现场实验、有关的太阳能设施,目前存在的主要困难及未来的应用前景等。 相似文献
83.
Differential presence of anthropogenic compounds dissolved in the marine waters of Puget Sound, WA and Barkley Sound, BC 总被引:1,自引:0,他引:1
Organic compounds were evaluated in March 2010 at 22 stations in Barkley Sound, Vancouver Island Canada and at 66 locations in Puget Sound. Of 37 compounds, 15 were xenobiotics, 8 were determined to have an anthropogenic imprint over natural sources, and 13 were presumed to be of natural or mixed origin. The three most frequently detected compounds were salicyclic acid, vanillin and thymol. The three most abundant compounds were diethylhexyl phthalate (DEHP), ethyl vanillin and benzaldehyde (∼600 ng L−1 on average). Concentrations of xenobiotics were 10-100 times higher in Puget Sound relative to Barkley Sound. Three compound couplets are used to illustrate the influence of human activity on marine waters; vanillin and ethyl vanillin, salicylic acid and acetylsalicylic acid, and cinnamaldehyde and cinnamic acid. Ratios indicate that anthropogenic activities are the predominant source of these chemicals in Puget Sound. 相似文献
84.
Gerardo?SeverinoEmail author Vladimir?Cvetkovic Antonio?Coppola 《Computational Geosciences》2005,9(4):155-177
We consider groundwater steady flow in a heterogeneous porous formation of random and stationary log-conductivity Y = ln K, characterized by the mean 〈Y〉, and the two point correlation function C
Y
which in turn has finite, and different horizontal and vertical integral scales I and I
v
, respectively. The fluid velocity V, driven by a given head drop applied at the boundary, has constant mean value U ≡ (U, 0, 0). Approximate explicit analytical expressions for transverse velocity covariances are derived. The adopted methodology
follows the approach developed by Dagan and Cvetkovic (Spatial moments of kinetically sorbing plume in a heterogeneous aquifers,
Water Resour. Res. 29 (1993) 4053) to obtain a similar result for the longitudinal velocity covariance. Indeed, the approximate
covariances of transverse velocities are determined by requiring that they have the exact first order variances as well as
zero integral scale (G. Dagan, Flow and Transport in Porous Formations (Springer, 1989)) , and provide the exact asymptotic limits of the displacement covariance of the fluid particles obtained
by Russo (On the velocity covariance and transport modeling in heterogeneous anisotropic porous formations 1. Saturated flow,
Water Resour. Res., 31 (1995) 129). Comparisons with numerical results show that the proposed expressions compare quite well in the early time
regime, and for Ut/I >100. Since most of the applications, like assessing the effective mobility of contaminants or quantifying the potential
hazards of nuclear repositories, require predictions over higher times the proposed approximate expressions provide acceptable
results. The main advantage related to such expressions is that they allow obtaining closed analytical forms of spatial moments
pertaining to kinetically sorbing contaminant plumes avoiding the very heavy computational effort which is generally demanded.
For illustration purposes, we consider the movement of one contaminant species, and show how our approximate spatial moments
compare with the numerical simulations. 相似文献
85.
Richardson BJ Tse ES De Luca-Abbott SB Martin M Lam PK 《Marine pollution bulletin》2005,51(8-12):975-993
Semi-batch seawater experiments were conducted to follow the uptake and release of selected PAHs (anthracene, fluorathene, pyrene and B[a]P) and organochlorine pesticides (-HCH, aldrin, dieldrin, p,p′-DDT) in semi-permeable membrane devices (SPMDs) and green-lipped mussels (Perna viridis). Mathematical models were applied to describe the uptake and elimination curves of the contaminants for SPMDs, and kinetic parameters, such as uptake rate constants, and equilibrium triolein/water partitioning coefficients were calculated. SPMD data showed a good fit to estimate rate constant and partition coefficient equations, but only those contaminants which partitioned mainly in the dissolved phase (-HCH and dieldrin) were well explained for mussels. Poor conformity of the other contaminants indicated mussels uptake by routes other than diffusion, such as ingestion of algae. An apparent equilibrium state was only noted for -HCH in mussels. Aldrin was not detected in mussels in the first few days of exposure, indicating potential metabolism of this compound. B[a]P was not detected in the triolein of SPMDs, which suggests that the membrane may act as a reservoir. Loss of spiked B[a]P from the triolein was evident in a depuration experiment, which may indicate transfer to the membrane. Rate constants for mussels were higher than those for SPMDs, but the reverse was true for partition coefficients. Overall, mussels and SPMDs had similar uptake rates for all compounds in this study, excluding p,p′-DDT and dieldrin. Contaminant elimination took place more rapidly in mussels, implying that SPMDs are better candidates for detecting episodic discharge of organic contaminants. 相似文献
86.
87.
地表稠油污染物地球化学研究现状 总被引:2,自引:1,他引:2
关于石油轻组分对环境的污染问题相对研究较多,而针对稠油污染物的研究则较薄弱。本文着重介绍了目前地表稠油污染物的研究进展,涉及稠油污染的潜在严重性和危害性,其赋存形态、迁移方式和演化机制,以及目前常用的修复方法。进一步开展稠油污染物在地表土壤以及水体中的地球化学特征及演化机制方面的研究工作,将有助于为稠油开采和炼制地区的环境保护和修复治理提供更多的科学依据。 相似文献
88.
1 INTRODUCTION Sediments are the ultimate sink for many hydrophobic contaminants and represent biologically important environmental habitats. Exposure of the sediment-associated contaminants is not only influenced by the fate and transport of sediment but also is influenced by a variety of physical, chemical, and biological processes that involve no net movement of sediments. These processes include pore water transport processes such as advection and diffusion, and sediment mixing process… 相似文献
89.
在简述半导体光催化理论及TiO2多相光催化作用近30年研究现状的基础上,重点对国内外一直处于空白状态的天然含钒金红石光催化性能进行研究。天然含钒金红石中部分Ti^4 被V^5 包括Fe^3 、Cu^2 和Zn^2 等杂质离子替代可引起其晶格畸变与缺陷。机械粉碎到70~80μm后可使其晶胞膨胀0.33%,原位加热700~1100℃其晶胞可膨胀0.93%~2.13%,淬火改性其晶胞收缩0.01%~0.07%。受热改性其体相中V^5 向表面偏析。对晶格畸变的修复可表现为晶面重构和再结晶作用及微应力释放作用。粉碎的金红石对卤代烃三氯乙烯和四氯乙烯具有一定的降解效果而表现出良好的光催化活性。加热1000℃,金红石对卤代烃的降解率明显提高。淬火1000℃和1100℃,金红石对卤代烃的降解速度大大加快。而电子辐射金红石对三氯乙烯的降解率则明显降低。通过52种金属氧化物和金属硫化物半导体矿物的初步研究,发现大多数金属氧化物矿物产生光电子的波长范围是249~777nm,吸收光主要是可见光。而大多数金属硫化物矿物产生光电子的最大波长大于921nm,吸收光主要是红外光,充分表明无机界具有光催化功能的半导体在可见光条件下就可以产生光电子与空穴。系统开展无机界矿物光催化作用研究,对揭示地球生命过程和环境演化有着不可替代的作用,对氧化降解地球表层系统中有机污染物尤其是不能自行降解的持久性有机污染物有着至关重要的作用。 相似文献
90.
天然铁锰氧化物及氢氧化物环境矿物学研究 总被引:40,自引:3,他引:37
带有表面电荷及含有变价元素的天然铁锰氧化物及氢氧化物具有良好的表面吸附与氧化还原等化学活性。在不同介质条件下 ,它们能不同程度地表现出对Cr6+,Pb2 +,Hg2 +,Cd2 +,As3 +,Cu2 +,Zn2 +,Co2 +,Ni2 +等重金属离子有吸附作用和对NO-3 ,PO3 -4 ,F-,S2 -等阴离子有吸附作用与氧化作用 ,并对苯酚、乙烷、乙烯、合成有机酸等有机物具有吸附和转化降解作用 ,还对CO2 ,NOx 和SO2 等具有分解转化作用。利用这些矿物的环境属性治理水体、土壤及大气污染的方法 ,具有成本低、效果好、无二次污染及有用金属可回收利用等优点 ,展现出广阔的环境矿物学研究与应用前景。 相似文献