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1.
超声-双氧水和亚铁离子体系处理含酚废水研究   总被引:3,自引:2,他引:3  
在实验装置上对超声-双氧水和亚铁离子体系联合处理含酚废水进行了实验研究。主要考察了废水初始pH值、初始双氧水浓度、超声功率、反应时间等因素对酚去除率的影响。实验结果表明:超声辐射可以在双氧水和亚铁离子体系氧化过程中起加速反应的作用,而且随着超声功率的增大,加速反应的能力增强;实验条件下废水初始pH值为4~6.8,初始双氧水浓度为140mg/L时酚去除效果最佳;超声-双氧水和亚铁离子体系处理含酚废水过程中苯酚的降解规律符合表现一级反应。  相似文献   

2.
吸附-双催化氧化降解苯胺、硝基苯废水   总被引:7,自引:0,他引:7  
苯胺、硝基苯废水利用吸附树脂吸附后,再利用过氧化氢作氧化剂,在亚铁离子和紫外光的双催化下氧化降解。通过对亚铁离子浓度、过氧化氢浓度等因素对光降解影响的考察,结果表明,在实验条件下,本氧化体系对苯胺、硝基苯废水有明显的降解效果,苯胺、硝基苯废水经该体系处理12h后,去除率最高分别达到99.7%和95.3%。  相似文献   

3.
纳氏试剂光度法是污水中氨氮测定广泛采用的方法,文章通过实验分析讨论实验室环境、水样预处理、酒石酸钾钠和显色温度、显色时间、pH值等实验条件对氨氮测定精准度的影响。实验结果表明:改善实验室环境,在2025℃、显色15min、显色后pH值为13的条件下,用滤膜代替滤纸,向酒石酸钾钠中加入NaOH煮沸浓缩定容能显著提高氨氮测定的精准度。  相似文献   

4.
钴的分光光度测定常用的显色试剂有亚硝基红盐、亚硝基甲苯酚、PAR、[2]、5 cl PADAB、[3]、DPPI、[4]、亦有采用多元络合物的[5]。中川元吉等研究了1(2噻唑偶氮)2萘酚(简称 TAN)与一些金属离子的反应,[6]提出在 PH 4~10,TAN 与 Co~(2+)生成组成  相似文献   

5.
文章采用高纯度气体二氧化氯作为消毒剂,以图书馆阅览室书刊表面作为研究对象,采用梅花点分布采样法对图书馆阅览室书刊表面进行取样,平板涂布法对采集到的病原微生物进行菌落计数。通过研究在不同浓度、不同杀菌时间、不同杀菌时间段条件下,气体二氧化氯对图书馆阅览室书刊表面的消毒效果,结果表明:气体二氧化氯浓度为0.6mg/m~3,杀菌时间为60min,杀菌时间段为20:00~21:00时,可以达到对书刊表面杀菌消毒的效果。  相似文献   

6.
对注空气低温氧化辅助热采废水的处理进行实验研究,先进行混凝处理,再分别采用Fenton氧化法和二氧化氯氧化法对废水氧化处理。结果表明后者效果较好,二氧化氯最佳投加量为300 mg/L,催化剂活性炭-Ni投加量为2.5 g/L,反应2 h,COD_(Cr)降低至129.14 mg/L,去除率达到95.29%,出水无色透明。二氧化氯氧化法适合于海上油田注空气低温氧化辅助热采废水的处理。  相似文献   

7.
钴的分光光度测定常用的显色试剂有亚硝基红盐[1]、亚硝基甲苯酚[1]、PAR、[2]、5 cl PADAB、[3]、DPPI、[4]、亦有采用多元络合物的[5]。中川元吉等研究了1-(2 噻唑偶氮)2-萘酚(简称TAN)与一些金属离子的反应,[6]提出在PH 4~10,TAN与Co~(2+)生成组成2∶1的红色络合物,Σ580nm=3.8×10~4,但未见用于具体样品分析,且需用氯仿萃  相似文献   

8.
甲醛吸收-副玫瑰苯胺分光光度法是测定环境空气中的二氧化硫的常用方法,该方法具有灵敏度高、选择性好等优点,但在实验分析过程中发现,该方法对实验室环境条件、反应条件、试剂的质量和实际操作要求严格。文章通过对影响空白值及检测结果的显色温度、显色时间、实验试剂、样品的采集及保存等关键因素进行实验分析,使校准曲线斜率和试剂空白吸光度值在给定的检测条件下满足检测方法标准的要求,为提高甲醛法测定空气中二氧化硫测量结果的准确性提供参考。  相似文献   

9.
利用厌氧颗粒污泥对烟气中SO2吸收生成的硫酸盐或亚硫酸盐废水进行处理,考察起始SO4^2-质量浓度、初始COD/SO4^2-、初始pH、接种污泥质量、亚铁离子等限制性生态因子对硫酸盐还原的影响。结果表明:在起始SO4^2-质量浓度800mg/L,初始COD/SO4^2-为3.0,pH值为7.0,接种污泥质量为31.10gVSS/L,添加亚铁离子的条件下,进行半连续试验,硫酸根去除率可迭70%。表明在COD/SO4^2-较低的条件下,各生态因子综合作用下,硫酸盐还原可得较好效果。  相似文献   

10.
本实验目的是研究草木灰对吸附亚甲基蓝的去除效果,探讨了亚甲基蓝初始量、吸附时间、pH值等对吸附效果的影响,并运用伪一级、伪二级反应动力学模型和Laugmuir、Freundlich等温线模型进行拟合。结果表明,草木灰对亚甲基蓝溶液的吸附在5 min~30 min速率比较快,约在65 min内达到吸附平衡,pH越大越有利于吸附,浓度在5mg/L时草木灰对亚甲基蓝的吸附最佳。与伪二级动力学曲线模型拟合效果较好,由Laugmuir等温线模型计算得出理论最大吸附容量Qm为2.275 mg/g,吸附性能优异。  相似文献   

11.
Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation.  相似文献   

12.
Urban ecological systems: scientific foundations and a decade of progress   总被引:9,自引:0,他引:9  
Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs.  相似文献   

13.
Urban gardens are important sources of sustenance for communities with limited access to food. Hence, this study focuses on food production in gardens in the Toledo metropolitan area in Northwest Ohio. We administered surveys to 150 garden managers from November 2014 to February 2015 in our attempt to better understand how neighbourhood racial composition and poverty levels are related to staffing and voluntarism, food production and distribution, the development of infrastructure, and the adoption of sustainability practices in urban gardens. The results from 30 gardens are presented in this paper. We used Geographic Information Systems to map the gardens and overlay the map with 2010 census data so that we could conduct demographic analyses of the neighbourhoods in which the gardens were located. Though the gardens were small – two acres or less – up to 46 varieties of food were grown in a single garden. Gardens also operated on small budgets. Food from the gardens was gifted or shared with friends, family, and neighbourhood residents. Gardens in predominantly minority neighbourhoods tended to have fewer institutional partners, less garden infrastructure, and had adopted fewer sustainable practices than gardens in predominantly White neighbourhoods. Nonetheless, residents of predominantly minority and high-poverty neighbourhoods participated in garden activities and influenced garden operations. Volunteering and staffing were racialised and gendered.  相似文献   

14.
In water stressed regions, water managers are exploring new horizons that would help in long‐range streamflow forecasts. Oceanic‐atmospheric oscillations have been shown to influence streamflow variability. In this study, long‐lead time streamflow forecasts are made using a multiclass kernel‐based data‐driven support vector machine (SVM) model. The extended streamflow records based on tree ring reconstructions were used to provide a longer time series data. Reconstructed data were used from 1658 to 1952 and the instrumental record was used from 1953 to 2007. Reconstructions for oceanic‐atmospheric oscillations included the El Niño‐Southern Oscillation, Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation, and North Atlantic Oscillation. Streamflow forecasts using all four oscillations were made with one‐year to five‐year lead times for 21 gages in the western United States. This is the first study that uses both instrumental and reconstructed data of oscillations in SVM model to improve streamflow forecast lead time. SVM model was able to provide “satisfactory” to “very good” forecasts with one‐ to five‐year lead time for the selected gages. The use of all the oscillation indices helped in achieving better predictability compared to using individual oscillations. The SVM modeling results are better when compared with multiple linear regression model forecasts. The findings are statistical in nature and are expected to be useful for long‐term water resources planning and management.  相似文献   

15.
Collisions with deer and other large animals are increasing, and the resulting economic costs and risks to public safety have made mitigation measures a priority for both city and wildlife managers. We created landscape models to describe and predict deer-vehicle collision (DVCs) within the City of Edmonton, Alberta. Models based on roadside characteristics revealed that DVCs occurred frequently where roadside vegetation was both denser and more diverse, and that DVCs were more likely to occur when the groomed width of roadside right-of-ways was smaller. No DVCs occurred where the width of the vegetation-free or manicured roadside buffer was greater than 40 m. Landscape-based models showed that DVCs were more likely in more heterogeneous landscapes where road densities were lower and speed limits were higher, and where non-forested vegetation such as farmland was in closer proximity to larger tracts of forest. These models can help wildlife and transportation managers to identify locations of high collision frequency for mitigation. Modifying certain landscape and roadside habitats can be an effective way to reduce deer-vehicle collisions.  相似文献   

16.
ABSTRACT: Mathematical models for predicting watershed surface flow responses are available, most of which are elaborate nonlinear numerical surface and channel flow models linked with infiltration models. Such models may be used to make predictions for ungaged areas, assuming an acceptable fitting of the model to the topography and roughness of the real system. For some application purposes, these models are impractical because of their complexity and expensive computer solutions. A procedure is developed that uses a complex model of an ungaged area to derive a simpler parametric nonlinear system model for repetitious simulation with input sequences. The predicted flow outputs are obtained with the simpler model at significant savings of money and time. The procedures for constructing a complex kinematic model of a 40 acre (161,880 m2) reference watershed and deriving the simpler system model are outlined. The results of predictions from both models are compared with a selected set of measured events, all having essentially the same initial conditions. Peak discharges ranged from 3 to 118 ft3/sec (0.085 to 3.34 m3/sec), which includes the largest event of record. The inherent limitations of lumped systems models are demonstrated, including the bias caused by their inability to model infiltration losses after rainfall ceases. Computer costs and times for the models were compared. The derived simple model has a cost advantage when repeated use of a model is required. Such an applications hydrologic model has an engineering tradeoff of reduced accuracy, and lumping bias, but is more economical for certain design purposes.  相似文献   

17.
Manganese entering impounded water will undergo a cyclic transformation. Oxidation precipitates manganese from top waters. At the bottom of the lake, biological activity will render manganese soluble by both intracellular as well as extracellular activity. The study was made to demonstrate that biological reduction and transformation, organometallic complexation, together with the presence of carbon dioxide and the lowering of pH all have some effect on the solubility of manganese. Dissolved manganese may be brought back to top waters during the lake overturn and therefore deteriorates the water quality.  相似文献   

18.
Water treatment residuals (WTR) can reduce runoff P loss and surface co-application of P-sources and WTR is a practical way of land applying the residuals. In a rainfall simulation study, we evaluated the effects of surface co-applied P-sources and an Al-WTR on runoff and leacheate bioavailable P (BAP) losses from a Florida sand. Four P-sources, namely poultry manure, Boca Raton biosolids (high water-soluble P), Pompano biosolids (moderate water-soluble P), and triple super phosphate (TSP) were surface applied at 56 and 224kgPha(-1) (by weight) to represent low and high soil P loads typical of P- and N-based amendments rates. The treatments further received surface applied WTR at 0 or 10gWTRkg(-1) soil. BAP loss masses were greater in leachate (16.4-536mg) than in runoff (0.91-46mg), but were reduced in runoff and leachate by surface applied WTR. Masses of total BAP lost in the presence of surface applied WTR were less than approximately 75% of BAP losses in the absence of WTR. Total BAP losses from each of the organic sources applied at N-based rates were not greater than P loss from TSP applied at a P-based rate. The BAP loss at the N-based rate of moderate water-soluble P-source (Pompano biosolids) was not greater than BAP losses at the P-based rates of other organic sources tested. The hazards of excess P from applying organic P-sources at N-based rates are not greater than observed at P-based rates of mineral fertilizer. Results suggest that management of the environmental P hazards associated with N-based rates of organic materials in Florida sands is possible by either applying P-sources with WTR or using a moderate water-soluble P-source.  相似文献   

19.
The SPARROW (SPAtially Referenced Regression on Watershed attributes) model was used to simulate annual phosphorus loads and concentrations in unmonitored stream reaches in California, U.S., and portions of Nevada and Oregon. The model was calibrated using de‐trended streamflow and phosphorus concentration data at 80 locations. The model explained 91% of the variability in loads and 51% of the variability in yields for a base year of 2002. Point sources, geological background, and cultivated land were significant sources. Variables used to explain delivery of phosphorus from land to water were precipitation and soil clay content. Aquatic loss of phosphorus was significant in streams of all sizes, with the greatest decay predicted in small‐ and intermediate‐sized streams. Geological sources, including volcanic rocks and shales, were the principal control on concentrations and loads in many regions. Some localized formations such as the Monterey shale of southern California are important sources of phosphorus and may contribute to elevated stream concentrations. Many of the larger point source facilities were located in downstream areas, near the ocean, and do not affect inland streams except for a few locations. Large areas of cultivated land result in phosphorus load increases, but do not necessarily increase the loads above those of geological background in some cases because of local hydrology, which limits the potential of phosphorus transport from land to streams.  相似文献   

20.
The interactions between humans, animals and the environment have shaped human values and ethics, not only the genes that we are made of. The animal rights movement challenges human beings to reconsider interactions between humans and other animals, and maybe connected to the environmental movement that begs us to recognize the fact that there are symbiotic relationships between humans and all other organisms. The first part of this paper looks at types of bioethics, the implications of autonomy and the value of being alive. Then the level of consciousness of these relationships are explored in survey results from Asia and the Pacific, especially in the 1993 International Bioethics Survey conducted in Australia, Hong Kong, India, Israel, Japan, New Zealand, The Philippines, Russia, Singapore and Thailand. Very few mentioned animal consciousness in the survey, but there were more biocentric comments in Australia and Japan; and more comments with the idea of harmony including humans in Thailand. Comparisons between questions and surveys will also be made, in an attempt to describe what people imagine animal consciousness to be, and whether this relates to human ethics of the relationships. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

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