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821.
在简要介绍了TiO2光催化降解机理的基础上,综述了影响纳米TiO2光催化性能的因素及提高其光催化能力的途径。 相似文献
822.
共基质条件下TNT降解菌的选育及其处理效果 总被引:3,自引:0,他引:3
选取SBR弹药销毁废水处理系统中的活性污泥作为菌源,在共基质条件下,经过驯化和筛选,分离出11株可降解TNT的单菌,从中选出生长速度较快的3株菌JT1,JT2,JT3进行了单菌及混菌降解能力测试,结果表明:混合菌JTH降解能力最强,其适宜环境条件为25℃~30℃,pH7.5~9.0,基质中添加2g/L葡萄糖可显著增强混菌JTH生长并可使24h内的TNT降解率达到96 1%;模拟废水的处理实验表明:混菌JTH对COD的去除率>80%,TNT降解率80%~90%;生物强化实验表明:以0.1的菌量污泥比在SBR系统中投加混合菌可使系统的出水COD稳定在100mg/L左右,出水TNT浓度<5mg/L。 相似文献
823.
Investigation into local peoples’ perceptions can produce useful information that could be incorporated into the decision-making
process to help resolve environmental problems. Within the arena of land degradation, a number of studies have also been conducted
to explore local peoples’ views of the problem. However, the perceptions of land-degrading practices of the general public
have so far not been actively solicited. This study aimed to contribute to this area of research by adopting the psychometric
scaling technique to empirically explore the lay public’s ecological risk perceptions of land-degrading activities in Minqin
County in Gansu Province, northern China. The primary data were collected via a questionnaire survey (n = 1,138) administered between 14 and 31 December 2002. The major findings of the survey were: (1) Respondents perceived the
ecological risks posed by different land-degrading activities to be different. (2) There was a considerable incongruence in
the way in which mining of groundwater was conceived by experts and laymen, respectively. (3) Respondents were pretty unsure
of expert knowledge. (4) Respondents’ ecological risk perceptions were significantly affected by their personal attributes.
As far as the policy implications of these findings are concerned, this study accentuates that we must be aware of, and involved
in, the environmental perceptions of the lay public in order to succeed in guiding any human-environment tensions along more
sustainable trajectories and navigating the transition to sustainability. 相似文献
824.
825.
826.
Soil erosion under different vegetation covers in the Venezuelan Andes 总被引:13,自引:0,他引:13
This comparative study of soil erosion considered different environments in an ecological unit of the Venezuelan Andes. The soils belong to an association of typic palehumults and humic dystrudepts. Soil losses were quantified by using erosion plots in areas covered by four types of vegetation, including both natural and cultivated environments. The highest soil erosion rate evaluated corresponded to horticultural crops in rotation: reaching a value of 22 Mg ha–1 per year. For apple tree (Malus sylvestris Miller) plots, soil losses reached values of 1.96 Mg ha–1 per year. Losses from pasture (Pennisetum clandestinum Hochst. ex Chiov.) plots, without livestock grazing, were as high as 1.11 Mg ha–1 during the second year of the experiment. The highest soil losses generated from plots under natural forest were equal to 0.54 Mg ha–1 per year. Environmental factors such as total and effective rainfall, runoff, and some soil characteristics as those related to soil losses by water erosion were evaluated. The type of management applied to each site under different land use type and the absence of conservation practices explain, to a large extent, the erosive processes and mechanisms. 相似文献
827.
水泥固定TiO2光催化降解苯酚水溶液的研究 总被引:2,自引:0,他引:2
以高压汞灯为光源。研究水泥固定TiO2在光反应器内光催化降解苯酚水溶液。通过正交试验,探讨了TiO2含量、初始溶液pH值,流速以及Fe3 浓度对光催化的影响。试验结果表明,在该固定床光催化反应器内,载体型TiO2对苯酚水溶液有明显的光解作用,最高光降率可以达到80%以上。在此基础上,提出了较为合理的处理工艺参数。另外,负载型光催化剂光照使用70h后,未见有TiO2脱落,且光催化活性无明显变化。这为制备负载型TiO2光催化剂提供了新的途径。 相似文献
828.
Olanike K. Adeyemo 《The Environmentalist》2003,23(4):297-306
Throughout the world, human use of water, and bad planning have led to drier and polluted rivers, lakes, and groundwater resources with dramatic effects on the natural ecosystems. Nigeria's vast freshwater resources are among those most affected by environmental stress imposed by human population growth, urbanization, and industrialization. Disposal and management of wastes in Nigeria present serious environmental problems. The usual methods of waste disposal in the country are: land filling, dumpsites, land spreads, water disposal, and incineration. Each of these methods has serious environmental implications because of their potential to pollute and contaminate underground and surface water bodies in the country. Major cities in Nigeria face serious water pollution crises, in which lack of environmental control of water-dependent activities (including domestic, agricultural, and industrial) play an important part. Fish and marine resources in the country face total collapse or extinction, due to over-fishing and destruction of marine life and natural habitats by pollution of water bodies. Unregulated and excessive use of pesticides for fishing and the deliberate disposal and dumping of toxic and hazardous wastes into water bodies are significant causes of massive fish kills and loss of aquatic life and habitats in the country. The protection of water quality and aquatic ecosystem as a vulnerable resource, essential to sustain life, development and environment is of utmost importance to prevent further pollution and degradation of Nigeria's freshwater resources. Integrating operational measures for safeguarding adequate levels of protection of endemic habitats remains a major challenge. There is therefore a need to examine in tandem the entire range of uses to which freshwater is put, and to design services which neither squander precious resources nor fail to respect other, competing and complementary water needs.This paper attempts to provide an overview of the Nigerian freshwater resources, to assess the pollution status of inland waters, identify the sources of pollution, and infer the consequent effect on fisheries resource. Recommendations were proffered on the strategies to employ to ensure that Nigerian fishery resources are adequately managed in order to address the issue of food security. 相似文献
829.
Removal of Cinnamic Acid Derivatives from Aqueous Effluents by Fenton and Fenton-like Processes as an Alternative to Direct Biological Treatment 总被引:2,自引:0,他引:2
Dionissios Mantzavinos 《Water, Air, & Soil Pollution: Focus》2003,3(3):211-221
The removal of various phenolic acids (p-coumaric, caffeic and ferulic acids), typically found in wastewaters of agricultural origin, from model effluents by chemical and biological means has been investigated. Chemical oxidation processes comprising hydrogen peroxide and a homogeneous or heterogeneous copper or iron catalyst were employed over a wide range of experimental conditions. Chemical oxidation is capable of removing most of the total organic carbon initially present in the effluent at relatively mild treatment conditions (i.e. reaction times up to 120 min and temperatures up to 80°C), while removal rates generally increase with increasing temperature, H2O2 and catalyst concentrations. The anaerobic degradability and toxicity of p-coumaric acid has been assessed using the biochemical methane potential and anaerobic toxicity assay respectively. p-Coumaric acid, at concentrations below about 1 g/L, is not toxic against methanogens and slowly degrades over a period of about 35 days at 35°C. In light of this, chemical oxidation may provide a promising alternative to direct biological treatment for either the partial or complete removal of phenolic acids at reasonable treatment times; the implications for wastewater treatment are discussed. 相似文献
830.