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861.
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
862.
研究了高岭石吸附水相中铅离子的动力学行为.结果表明:高岭石对水溶液中铅离子的吸附是一个复杂的非均相固液反应,从动力学角度来看,大致可以分为2个阶段:初期阶段反应速度快,动力学过程复杂,有待于深入研究;后期阶段反应速度较慢,并符合一级反应动力学方程.吸附速率常数k与温度T之间的关系符合阿累尼乌斯公式,吸附的活化能为Ea=26.44 J/mol,吸附的频率因子A=603s-1.ln(k/T)与1/T之间的关系符合Eyring公式,其活化焓△H=23.94J/mol,活化熵△S=-200J/K·mol.同时,k与铅离子初始浓度呈负相关性,与高岭石用量、介质pH值呈正相关性. 相似文献
863.
864.
新型固相萃取器用于污染水样中痕量杀虫剂的浓缩及热解吸气相色谱-质谱分析 总被引:3,自引:0,他引:3
WANGLi-Li HOSAKAAkihiko WATANABEChuichi 《环境化学》2003,22(3):267-270
1 IntroductionSolid phasemicro extraction (SPME)asasimpleandrapidextractiontechniqueiswidelyusedinvariousareasforextractingdiluteanalytesfromliquid ,gaseousandsolidsamplesbecauseofitshighextractionefficiency[1 ].Recently ,astirbarsorptiveextraction (SBSE… 相似文献
865.
为研究安全帽安全性与保护性问题,利用落锤冲击实验,对不同材质安全帽吸能率、冲击力峰值进行研究。结果表明:随冲击能量增加,安全帽受冲击力峰值呈指数倍增长,吸能率呈指数倍下降;ABS树脂与玻璃钢材质安全帽头模受冲击力峰值小于HDPE材质安全帽;当冲击能量大于60 J,HDPE材质安全帽丧失保护功能;ABS安全帽能够承受最大冲击力能量值为70 J,玻璃钢安全帽最大承载力高于ABS树脂安全帽。研究结果可为安全帽质量设计提供理论依据。 相似文献
866.
通过试验研究,建立了硝酸-氢氟酸-高氯酸消解、石墨炉原子吸收分光光度法测定生活垃圾堆肥产品中的镉。该方法的检出限为0.01mg/kg(按称取0.5g试样消解定容至50mL计算),用于不同地域堆肥样品中镉的测定,其相对标准偏差(RSD)在5.78%~11.9%之间,加标回收率介于88.0%~106.0%之间,可作为一种较理想的检验堆肥产品质量的方法。 相似文献
867.
868.
Elo H 《Die Naturwissenschaften》2008,95(5):399-402
The ionization energy of one-electron ions can be calculated from a well-known equation that is based on quantum mechanics and on the Bohr model, but no theoretically justified equation is available for the calculation of the ionization energies of multi-electron ions. I report here simple empirical relationships between the ionization energies of one-, two- and three-electron ions of elements whose atomic numbers are Z, Z + 1 and Z + 2. On the basis of these relationships, an equation was constructed for the calculation of the ionization energies of two- and three-electron ions (IE(2el)(Z) and IE(3el)(Z), respectively) as a function of Z only: [equation: see text] where N = the number of electrons, i.e. 2 or 3. For N = 3, this equation is only valid when Z > N, being inaccurate for the neutral Li atom. Graphs of the difference between calculated and experimental values of the ionization energies as a function of Z reveal inaccurate experimental results that are impossible to detect by inspection of the ionization energy itself. On the basis of the present results, more accurate values can be predicted for these ionization energies. A striking example is the inaccuracy of the traditional handbook value of IE(3el)(Fe). 相似文献
869.
Yu Kuang Yi Guo Jiaqi Chai Jing Shang Jiali Zhu Svetlana Stevanovi Zoran Ristovski 《环境科学学报(英文版)》2020,32(1):184-193
Soot particles,mainly coming from fuel combustion,affect climate forcing through absorbing light and also result in adverse human health outcomes.Though biodiesel or additives blending with diesel was considered environmentally friendly,the understanding on absorbing and oxidative capacity of soot emitted from them are still unclear.The watersoluble organic carbon(WSOC) content,surface chemical structure,light absorption and oxidative potential(OP~(DTT)) of soot from biodiesel/diesel and chemicals/diesel blends were investigated utilizing total organic carbon analyzer,X-ray photoelectron spectrometer,ultraviolet–visible spectrophotometry and dithiothreitol(DTT) assay.The differences and correlations between soot properties were statistically analyzed.Chemicals/diesel blends soot owned significantly higher WSOC content,ratio of mass absorbing efficiency(MAE) in250 and 365 nm(E_2/E_3),OP~(DTT),and higher surface carbonyl content.Coconut biodiesel/diesel blends soot contained evidently higher aromatic carbon–oxygen single bond(Ar_C–O)content,and higher MAE365.The individual comparison of biodiesel/diesel blends showed20% coconut biodiesel blend owned the lowest WSOC,E_2/E_3 and OP~(DTT),while highest Ar_C–O and MAE365,representing strongest absorbing properties.Association analysis showed OP~(DTT)was significantly positively correlated with WSOC.Further,the evident negative correlation between MAE365 and OP~(DTT) was observed.Our results showed coconut biodiesel/diesel blends soot induced lower levels of oxidative potential,whereas absorption of light was higher,which have far reaching consequences on climate forcing.Therefore,it is important to evaluate the balance point between light-absorbing properties and oxidative potential,under the wide use of biodiesel. 相似文献
870.
利用紫外-可见吸收光谱、激发发射矩阵荧光光谱(EEMs)并结合平行因子分析(PARAFAC),分析黄河兰州段水体有色溶解有机质(CDOM)的组成、空间分布以及来源.结果表明,黄河兰州段水体CDOM可能是由芳香性结构的小分子组成,解析出的4个组分中,类蛋白质(1个组分)含量最多,占总荧光强度的51.06%,类腐殖质(2个组分)次之,占36.74%,非类腐殖质(1个组分)最少,占12.20%,类蛋白质组分和类腐殖质组分来源不同.CDOM属于"类蛋白质-类腐殖质"复合主导型,以生物来源的类蛋白质为主.从上游到下游河段,CDOM的空间分布格局大体有一个先降低再升高再降低的过程,其趋势主要受到类蛋白质含量变化的影响.类蛋白质的含量受到了居民/商业污水排放、河岸及水上餐饮、娱乐设施、船舶运输以及少量工业企业废水排放等各种高强度人为活动干扰.黄河流经兰州市受到了一定的内源污染,建议对黄河兰州段水体进行内源污染的控制. 相似文献