共查询到16条相似文献,搜索用时 46 毫秒
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《矿山资源开发利用与环境保护》2002,(5):21-21
颗粒物污染是城市大气污染中的一个突出问题。颗粒物按粒径可分为降尘和飘尘:降尘是指粒径大于10微米的固体颗粒物,在空气中停留时间较短,在呼吸作用中又可被有效地阻留在上呼吸道上,因而对人体危害较小;飘尘是指粒径10微米以下的固体颗粒物,能在空气申长时间悬浮,易经呼吸侵入人体的肺部组织,因而对人体健康危害较大。 相似文献
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从柴油污染土壤中筛选分离出一株高效降解柴油的菌株CY-1,考察了自然衰减修复、生物刺激修复、生物强化修复以及生物刺激-生物强化联合修复等4种修复方法对土壤中柴油的降解能力及降解过程中几种土壤微生物酶活性的变化。实验结果表明:该菌为假单胞菌属;采用生物刺激-生物强化联合修复初始柴油质量分数为2.70%的柴油污染土壤,经过31 d的降解,柴油质量分数降至1.09%,柴油去除率达59.6%;经生物刺激-生物强化联合修复,土壤脱氢酶活性和荧光素二乙酸酯水解酶活性最高;通过生物刺激处理可使土壤脲酶活性和磷酸酶活性达到最高。 相似文献
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介绍了生物柴油的特性、能耗及生物柴油的制备方法(直接混合法、微乳液法、高温热裂解法、酯交换法、超临界甲醇法)和生物柴油在工业应用巾存在的主要问题,阐述了国内外生物柴油的产业发展现状,展望了该产业在我田的发展前景。 相似文献
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化工厂排放SO2对周围植物的影响 总被引:6,自引:0,他引:6
对某厂区及常年盛行风下风向地区植物受SO2危害情况进行了调查,并测定了部分植物叶片中的硫含量。从植物叶片中的硫含量可间接地判断大气被SO2污染的程度及植物对SO2吸收与抵抗能力的强弱。 相似文献
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目前生物柴油产品的价格约是石油柴油的3倍,将其作为石油柴油的替代品进行工业化和商品化生产还不太可能。目前的生物柴油生产者仍然在使用缓慢且高能耗的“高温高压”方法或化学方法,后者不能得到成本效益指标满足美国材料实验协会(ASTM)标准的生物柴油。BIOX公司正在将多伦多大学David Boocock发明的技术(美国专利号6642399和6712867)工业化。 相似文献
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采用UASB-SBR-絮凝工艺处理地沟油制生物柴油废水,考察了各个阶段的废水处理效果。实验结果表明:UASB稳定运行阶段进水COD约为15000mg/L时,COD去除率约为87%,出水COD在2500mg/L以下,出水挥发性脂肪酸(VFA)浓度为4~6mmol/L,最佳容积负荷为15.0kg/(m3·d);采用SBR处理UASB出水,当容积负荷为1.5kg/(m3·d)时,出水COD在200mg/L以下,COD去除率在83%以上,ρ(NH3-N)在5mg/L以下,TP约为25mg/L。向SBR出水中加入质量分数为5%的聚合氯化铝进行化学除磷,加入量为5mL/L,处理后废水TP为4~6mg/L。处理后废水的COD,ρ(NH3-N),TP均达到CJ343-2010《污水排入城市下水道水质标准》的A类要求。 相似文献
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The use of biodiesel as fuel from alternative sources has increased considerably over recent years, affording numerous environmental benefits. Biodiesel an alternative fuel for diesel engines is produced from renewable sources such as vegetable oils or animal fats. However, the high costs implicated in marketing biodiesel constitute a major obstacle. To this regard therefore, the use of waste frying oils (WFO) should produce a marked reduction in the cost of biodiesel due to the ready availability of WFO at a relatively low price.In the present study waste frying oils collected from several McDonald’s restaurants in Istanbul, were used to produce biodiesel. Biodiesel from WFO was prepared by means of three different transesterification processes: a one-step base-catalyzed, a two-step base-catalyzed and a two-step acid-catalyzed transesterification followed by base transesterification. No detailed previous studies providing information for a two-step acid-catalyzed transesterification followed by a base (CH3ONa) transesterification are present in literature. Each reaction was allowed to take place with and without tetrahydrofuran added as a co-solvent. Following production, three different procedures; washing with distilled water, dry wash with magnesol and using ion-exchange resin were applied to purify biodiesel and the best outcome determined. The biodiesel obtained to verify compliance with the European Standard 14214 (EN 14214), which also corresponds to Turkish Biodiesel Standards. 相似文献
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Diauddin R Nammari Marcia Marques William Hogland Lennart Mathiasson Lars Th?rneby Lennart M?rtensson 《Waste management & research》2007,25(2):109-118
This paper focuses on the volatile organic compound emissions from baled municipal solid waste (MSW). The analytical methodology was based on sampling with adsorbent tubes once a month during seven occasions within a time period of 1 year. Automated analyses were carried out on-line work-up with thermal desorption directly connected to a gas chromatograph-mass spectrometer. The effect of different baling techniques, cylindrical and rectangular baling was compared. It was found that cylindrically baled MSW emitted larger concentration of esters than their rectangular counter parts. Conversely, aromatic compounds emissions dominated in rectangularly baled MSW. This indicates that different degradation mechanisms operate in the waste bales. Cylindrical and rectangular bales are generally wrapped with six layers of 250 microm thick low density polyethylene (LDPE). It was observed that by wrapping an extra six layers of LDPE film onto the bales, the emissions from cylindrical bales increased while emissions from the rectangular counterpart decreased. Over time, the volatile organic compound emissions from cylindrical bales decreased two orders of magnitudes from 96.2 +/- 20.8 microg m(-3) in September 2003 to 0.80 +/- 0.07 microg m(-3) in July 2004. The rectangular bales exhibited an almost identical relative emission reduction from 54.4 +/- 4.3 microg m(-3) in September 2003 to 0.46 +/- 0.02 microg m(-3) in July 2004. Future work will concentrate on full-scale storages, taking into account waste type, storage size, temperature development and the different baling techniques among other variables. 相似文献
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C. Borrego O. Tchepel A. Monteiro N. Barros A. Miranda 《Water, Air, & Soil Pollution: Focus》2002,2(5-6):487-499
The main objective of this work is to analyse how uncertainties in emission data of nitrogen oxides (NOx) and volatile organic compounds (VOC), originated from road traffic, influence the model prediction of ozone (O3) concentration fields. Different methods to estimate emissions were applied and results were compared in order to obtain their variability. Based on these data, different emission scenarios were compiled for each pollutant considering the minimum and the maximum values of the estimated emission range. These scenarios were used as input to the MAR-IV mesoscale modelling system. Simulations have been performed for a summer day in the Northern Region of Portugal. The different approaches to estimate NOx and VOC traffic emissions show a significant variability of absolute values and of their spatial distribution. Comparison of modelling results obtained from the two scenarios presents a dissimilarity of 37% for ozone concentration fields as a response of the system to a variation in the input emission data of 63% for NOx and 59% for VOC. Far beyond all difficulties and approximations, the developed methodology to build up an emission data base shows to be consistent and an useful tool in order to turn applicable an air quality model. Nevertheless, the sensitivity of the model to input data should be considered when it is used as a decision support tool. 相似文献
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《Spill Science & Technology Bulletin》1999,5(5-6):353-355
Experiments using biodiesel derived from vegetable oils have demonstrated the considerable potential for removing crude oil from contaminated beaches. During laboratory studies in small boxes, contaminated sand treated with biodiesel also demonstrated the rapid biodegradation of the crude oil. Water soluble components were washed through the sand columns and these components subsequently precipitated with cold storage. This solid fraction was not soluble in organic solvents but could be re-dissolved in dilute acid. The sediments after four weeks were black in colour due to the precipitation of metal sulphides although no H2S was generated because the pH of the seawater kept the sulphides in solution. Further work is investigating which components of the oil were degraded and what products were formed. 相似文献