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851.
852.
Vaiskunaite R Baltrenas P Spakauskas V 《Environmental science and pollution research international》2005,12(5):297-301
Aim, Scope and Background Human economic activities cause emissions of various pollutants of an organic nature: butanol, butyl acetate, methanol, formaldehyde,
phenol, benzene, toluene, xylene, etc. These compounds are emitted to atmosphere by various enterprises of food, chemistry,
wood processing industries, from transportation means, agricultural enterprises, etc. Therefore, when purifying air from these
pollutants, it is necessary to apply efficient and inexpensive air purification methods. In this dimension, the biological
air purification is chosen from all possible air cleaning methods. An experimental biofilter with the activated charge of
pine bark was developed at the Department of Environment Protection of the Vilnius Gediminas Technical University. In the
course of the experimental investigation, it was determined that this air purification method is efficient. Filter efficiency,
when purifying air of volatile organic compounds (butanol, butyl acetate and xylene), to a great extent, depending on the
nature and concentrations (up to 100 mg/m3) of pollutants injected, might go up to
70-98%. The mathematical model of the biofilter was developed based on the research results and fully taking into consideration
physical, chemical, and biological processes going on during its operations.
Main Features The aim of this article is to determine biodegradation constant , absorption capacity , and half empiric expressions of
filter efficiency. Knowing this, it is possible to find out the dependence of the filter efficiency on the operational parameters
of the filter (i.e. on the concentrations and the height of biocharge of the initial pollutants (butanol, butyl acetate, xylene)
fed through it).
Conclusions With the help of mathematical modeling, the biodegradation constants and absorption capability of volatile organic compounds
(butanol, butyl acetate, and xylene) fed into the biofilter charged with the activated pine bark and used for the cleaning
of volatile organic compounds, as well as the efficiency of the biofilter in half empiric expression, have been established.
It has been discovered that the constant of pollutant biodegradation is a value inverse to the time during which the amount
of pollutants in the filter becomes times higher. It is rather complicated to carry out theoretical calculation of the biodegradation
constant at a molecular level, therefore this constant has been established based on the results obtained in the course of
research. The equations describing pollutant dynamics in the filter charge and the air cleaning processes going on in it have
been derived from diffusion equations in a mobile medium. The modeling helped to find out the absorption capacity of the
examined pollutants, which by its numeric value is equal to the volume unit of the absorbed gas amount. The latter factor,
the same as the biodegradation constant, was determined basing on the experimental results. Mathematical modeling brought
a range of formulas expressing dependences of each pollutant's efficiency on its initial concentrations and filter charge
height.
Recommendation /Outlook. Based on the experimental data, a mathematical model has been developed which will allow the measuring of the filter
efficiency not only with regard to the absorption and biodegradation of the pollutants under examination, but also with regard
to other pollutants and their compounds, etc., having an impact on the filter performance. The results of the mathematical
modeling have revealed that the modeling of processes going on in the filter is much simpler than isthe performance of long
and costly experiments. The developed mathematical model makes it possible to measure the filter efficiency at the present
moment. 相似文献
853.
泥炭树脂颗粒对水溶液中十二烷基苯磺酸钠的去除 总被引:1,自引:0,他引:1
泥炭树脂颗粒对水溶液中十二烷基苯磺酸钠 (SDBS)具有很好的去除效果。数据分析表明 ,Freundlich和 Langmuir吸附等温方程可以很好地描述这一过程。通过 L angmuir方程计算出颗粒对 SDBS的最大吸附量为 3 3 .3 3 mg·g- 1。在试验条件下 ,吸附量随着 SDBS的初始浓度增加而增加 ,当溶液的初始 p H在 4~ 8的范围时 ,颗粒对 SDBS吸附量变化很小。溶液的初始浓度对吸附速率产生明显影响 ,浓度越低吸附速率越快 ,达到吸附平衡所需的时间越短。准二级动力学模型能够很好地描述颗粒对 SDBS的吸附过程。 相似文献
854.
855.
对粤西某石化城河段几种主要污染物进行了容量计算 ,发现即使工业污染源全部达标 ,其水质状况与目标的差距仍较大 ,据此提出小容量河流的观点。为保护水环境 ,结合流域实际情况 ,本文提出改变以往单纯依靠工业污染源达标控制手段 ,而采用多手段相结合的综合管理模式来改善水环境的观点 ,并以中长期水环境规划年内目标值为依据 ,分析了本方法的有效性、经济性和可操作性 ,由此对其他具相似条件小容量河流的城市水环境管理起到借鉴性作用。 相似文献
856.
粉煤灰吸附性能研究是当前环境科学领域中的一个研究热点 ,但原状粉煤灰的吸附效果不理想。本文报道的用煅烧 -碱溶法制得类沸石吸附剂的比表面积为 112 .6m2 / g、孔隙率为 83 .1% ,分别是改性前的 40 .2 2和 1.67倍。用此类沸石吸附剂来处理浓度为 2 0 0mg/L的模拟含铅废水 ,去除率为 84.87% ,吸附容量为 3 3 .94mg/ g ,分别是改性前的3 1.13和 3 1.42倍 ,处理效果优于市售一级活性炭。并用 0 .1mol/L的HCl溶液和饱和NaCl溶液再生此吸附剂 ,解吸率达到了 98%以上 ,此再生的类沸石吸附剂处理含铅废水的去除率也达到了 83 %以上 相似文献
857.
几种土壤的基本理化性质与Cu2+吸附的关系 总被引:6,自引:0,他引:6
研究了大冶市几种类型土壤的基本性质及与Cu2+吸附的关系,结果表明,土壤对Cu2+的吸附量随其CEC值(记为CEC)而变化,供试土壤的Cu2+吸附量由大到小的顺序为石灰土→水稻土→潮土→棕红壤.加入铜浓度为5 mmol·L-1时11个土壤对铜的吸附量x((mol·g-1)与CEC的直线相关方程为x(Cu2+) = 2.018×CEC + 24.4 (r=0.7066).而影响CEC的因素,如Ph、粘粒含量及其组成、有机质、比表面等,也是决定Cu2+吸附量的重要因素. 相似文献
858.
MaryCarol Rossiter Diana Cox-Foster Mamdouh M. Abou-Zaid Diane Bergeron 《Chemoecology》1996,7(2):74-84
Summary A standard buffer (5 mM phosphate at pH 7) which is used to extract protein from insect eggs provided complete protein solubility for eggs from three of four tree-feeding lepidopteran species: obliquebanded leaf roller (Choristoneura rosaceana), forest tent caterpillar (Malacosoma disstria), and the eastern tent caterpillar (Malacosoma americanum). Under the same extraction protocol, egg proteins from the gypsy moth (Lymantria dispar), remained nearly insoluble. An array of methods typically used to solubilize insect egg proteins were tried and all but the most denaturing (2% SDS) were ineffective. Extraction buffers with typically high pH values were then evaluated. The results indicated that 1) solubility of gypsy moth egg proteins was pH dependent, and full solubility of most egg proteins required the extraction buffer to have a pH of 12 or more prior to the addition of eggs. We also determined that 2) the gypsy moth egg has a buffering capacity which must be surpassed for complete protein extraction, 3) low salt/high pH buffers gave slightly higher total protein values than did high salt/high pH buffers, 4) parental nutritional history (host species utilized) and egg developmental state (pre-embryonatedvs postembryonated/pre-hatch) were unrelated to the requirements for complete egg protein solubilization, and 5) the presence of soluble phenolics, compounds that have the potential to bind to protein and cause insolubility, was confirmed for the gypsy moth egg with 2-D paper chromatography and several other tests. Based on these results, we present a hypothesis about the cause of egg protein insolubility in the gypsy moth. 相似文献
859.
Who is susceptible and why? An agent-based approach to assessing vulnerability to drought 总被引:2,自引:2,他引:0
In this paper, we specify susceptibility to drought from a psychology-based bottom-up perspective. On the basis of the protection motivation theory (Rippetoe and Rogers in J Pers Soc Psychol 52(3):596–604, 1987), we developed the protection-capacity model (Krömker and Mosler in Global environmental change in Alpine regions: impact, recognition, adaptation, and mitigation. Edward Elgar, Cheltenham, pp 93–112, 2002) to analyse the susceptibility with respect to the protection capacity of agents. The protection capacity is determined by the agents’ subjective assessment of the situation, which consists of the appraisal of threat, on the one hand, and the coping appraisal, on the other hand. Additionally, the protection-capacity model specifies several factors which influence the two central appraisal processes. Empirical data were collected in interviews with experts and with a total of 65 exemplarily selected households which are typical for the respective case study regions (Andhra Pradesh, India; Algarve and Alentejo, Portugal; Volgograd and Saratov, Russia). The data were analysed with the help of fuzzy set methodology. Results show that the households of the Indian region are the most susceptible when compared to those of the Russian region with ‘low’ and to households of the Portuguese region with a ‘very low’ degree of susceptibility. Moreover, we identified subgroups within the regions which are characterized by different degrees of susceptibility and a different profile of factors influencing susceptibility. Altogether, the agent-based perspective allows identifying relevant factors that need to be addressed to minimize susceptibility of the population and special subgroups. However, the results are not representative for the case study regions because of the small database. Additionally, more effort is needed to validate the findings. 相似文献
860.
Application of fuzzy models to assess susceptibility to droughts from a socio-economic perspective 总被引:1,自引:1,他引:0
Lilibeth A. Acosta-Michlik K. S. Kavi Kumar Richard J. T. Klein Sabine Campe 《Regional Environmental Change》2008,8(4):151-160
By combining the concepts of environmental stress, state susceptibility and environmental crisis, “Security Diagram” (SD)
provides a quantitative approach to assessing environmental change and human security. The SD is a tool that clearly presents
in a diagram the security situation of a population or region affected by a particular environmental crisis. Its underlying
concept emphasises that the higher the level of environmental stress and socio-economic susceptibility, the higher the probability
of the occurrence of crisis. Focusing on drought, this study analyses the susceptibility of case study regions in India, Portugal,
and Russia from a socio-economic perspective. A conceptual framework of socio-economic susceptibility is developed based on
the economic development theories of modernisation and dependency. Fuzzy set theory is used to generate susceptibility indices
from a range of national and sub-national indicators, including financial resources, agricultural dependency and infrastructure
development (for economic susceptibility), and health condition, educational attainment and gender inequality (for social
susceptibility). Results indicate that socio-economic susceptibility over the period 1980–1995 was highest in India, followed
by Russia and (since 1989) lowest in Portugal. Globalisation is likely to contribute to changes in the level of socio-economic
susceptibility over time. Moreover, specific social and economic structures unique in each country (e.g., the role of women
in society in India, the socialist legacy in Russia) may explain differences in susceptibility between the case study regions.
相似文献
Sabine CampeEmail: |