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31.
WANG Hai-ling FEI Zheng-hao CHEN Jin-long ZHANG Quan-xing XU Yan-hua 《环境科学学报(英文版)》2007,19(11):1298-1304
The adsorption behavior of p-aminobenzoic acid and o-aminobenzoic acid onto the different polymeric adsorbents was systematically investigated as a function of the solution concentration and temperature.Experimental results indicated that the equilibrium adsorption data of the four polymeric adsorbents fitted well in the Freundlich isotherm.The adsorption capacity of multi-functional polymeric adsorbent NJ-99 was the highest,which might be attributed to the strong hydrogen-bonding interaction between the amino groups on the resin and the carboxyl group of aminobenzoic acid.The adsorption capacity of o-aminobenzoic acid onto any adsorbent was higher than p-aminobenzoic acid.Thermodynamic studies suggested the exothermic,spontaneous physical adsorption process.Adsorption kinetics results showed that the adsorption followed the pseudo-second-order kinetics model and the intraparticle mass transfer process was the rate-controlling step. 相似文献
32.
基于物理过程的矿区地下水污染风险评价 总被引:4,自引:1,他引:3
目前国内外所做的地下水污染风险评价的实例研究一般都是从地下水的脆弱性研究出发,并未过多地考虑特征污染物对污染后果的影响.脆弱性是环境对污染物的自然敏感性,而地下水污染评价中更应当体现出污染物在地下水中的迁移分布特性.为了完善地下水污染风险评价的理论和方法,以某尾矿区为例提出了基于物理过程的地下水污染风险评价方法,在污染发生之前,根据经济社会的敏感性条件和污染物将来可能的分布范围,事先划分各个污染风险等级在含水层空间上的分布范围,然后据此反推各个风险等级所对应的污染物源强,以此作为地下水污染风险评价等级的划分标准,通过对污染物在包气带和含水层中的运移进行数值模拟来评价尾矿区地下水的污染风险.结果表明,这种基于物理过程的地下水污染风险评价方法可以给出污染物浓度和风险水平在空间和时间上的分布规律,对于单个点状的污染场地来说,具有详尽的风险表征方式,优于以往基于含水层固有脆弱性指数法的风险评价方法,该方法适用于现有污染场地的风险评价、场地优化选址和为场地建设提供设计参数. 相似文献
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通过监测和田地区生态修复项目实施后所取得生态效益的结果表明,生态修复项目实施后,由于项目区风速降低,温度和相对湿度的变化减少,提高了植被盖度,降低了风蚀量,促进了成土作用的进行,从而逐渐改善了土壤的理化性质。 相似文献
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36.
Kelli Larson 《Journal of the American Water Resources Association》2009,45(4):879-893
Abstract: Surface water resources in urban areas serve multiple functions ranging from recreation to wildlife habitat. As a result, diverse values influence people’s views about resource protection, potentially leading to conflicting interests. In metropolitan Portland, Oregon, natural resource planning has recently focused on habitat restoration as well as stormwater and pollution mitigation, especially through the protection of riparian areas. Due to opposition over proposed regulations in the study region, this research examines public attitudes about an array of resource management efforts. The primary research question is: what is the extent of positive–negative attitudes about water resource protection, and what theoretical dimensions underlie diverse judgments? After empirical survey results are presented, I outline a conceptual approach for future assessments of environmental attitudes while highlighting important value‐based dimensions of judgments. Although flexible, the framework allows broad comparisons to advance knowledge about the social acceptability of varied water resource management approaches across diverse places and contexts. 相似文献
37.
The aim of this study was to investigate the mechanism of cadmium (Cd) adsorbed by microalgae Chlamydomonas reinhardtii (C.reinhardtii). The kinetic and adsorption isotherm of the process could be well described by mathematical models. Chemical modification experiments and Fourier transform infrared spectra indicated that carboxyl and amine groups were the important functional groups for adsorption of Cd. The maximum contribution of physical adsorption in the overall adsorption process was evaluated as 5.5%... 相似文献
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39.
Sheryl Luzzadder-Beach 《Environmental management》1995,19(3):383-392
What size sample is sufficient for spatially sampling ambient groundwater quality? Water quality data are only as spatially accurate as the geographic sampling strategies used to collect them. This research used sequential sampling and regression analysis to evaluate groundwater quality spatial sampling policy changes proposed by California's Department of Water Resources. Iterative or sequential sampling of a hypothetical groundwater basin's water quality produced data sets from sample sizes ranging from 2.8% to 95% coverage of available point sample sites. Contour maps based on these sample data sets were compared to an original (control), mapped hypothetical data set, to determine at which point map information content and pattern portrayal are not improved by increasing sample sizes. Comparing series of contour maps of ground water quality concentration is a common means of evaluating the geographic extent of groundwater quality change. Comparisons included visual inspection of contout maps and statistical tests on digital versions of these map files, including correlation and regression products. This research demonstrated that, down to about 15% sample site coverage, there is no difference between contour maps produced from the different sampling strategies and the contout map of the original data set. 相似文献
40.
Lizhu Wang John Lyons Paul Kanehl 《Journal of the American Water Resources Association》2002,38(3):663-680
ABSTRACT: We evaluated the effectiveness of watershed‐scale implementations of best‐management practices (BMPs) for improving habitat and fish attributes in two coldwater stream systems in Wisconsin. We sampled physical habitat, water temperature, and fish communities in multiple paired treatment and reference streams before and after upland (barnyard runoff controls, manure storage, contour plowing, reduced tillage) and riparian (stream bank fencing, sloping, limited rip‐rapping) BMP installation in the treatment subwatersheds. In Spring Creek, BMPs significantly improved overall stream habitat quality, bank stability, instream cover for fish, abundance of cool‐ and coldwater fishes, and abundance of all fishes. Improvements were most pronounced at sites with riparian BMPs. Water temperatures were consistently cold enough to support coldwater fishes such as trout (Salmonidae) and sculpins (Cottidae) even before BMP installation. We observed the first‐time occurrence of naturally reproduced brown trout (Salmo trutta) in Spring Creek, indicating that the stream condition had been improved to be able to partially sustain a trout population. In Eagle Creek and its tributary Joos Creek, limited riparian BMPs led to localized gains in overall habitat quality, bank stability, and water depth. However, because few upland BMPs were installed in the subwatershed there were no improvements in water temperature or the quality of the fish community. Temperatures remained marginal for coldwater fish throughout the study. Our results demonstrate that riparian BMPs can improve habitat conditions in Wisconsin streams, but cannot restore coldwater fish communities if there is insufficient upland BMP implementation. Our approach of studying multiple paired treatment and reference streams before and after BMP implementation proved effective in detecting the response of stream ecosystems to watershed management activities. 相似文献