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641.
通过添加磁种和混凝剂,用高梯度磁分离方法去除污水中正磷酸盐污染物,并对工艺参数进行了探讨. 相似文献
642.
介绍抚顺醇醚化学厂醇醚生产废水的排放与水质特点 ,结合工艺流程介绍处理工艺设计和技术参数。几年来的运行结果表明 ,采用生物滤池 生物接触氧化 纤维球过滤三级工艺处理醇醚表面活性剂废水 ,处理效果良好 ,出水CODCr<10 0mg/L ,SS <15mg/L ,滤后水可用于厂区绿化。 相似文献
643.
钙基脱硫剂高温固硫性能的影响因素试验分析 总被引:4,自引:0,他引:4
对含硫量为1.51%的大同煤,在不同的气氛和工况下加入钙基脱硫剂,并辅以添加剂,在800—1200℃的高温下开展了较为系统的试验和分析。与CaCO3和CaO相比,Ca(OH)2具有更好的高温固硫性能;Ca(OH)2、CaCO3和CaO在900℃左右均表现出很好的固硫率;氧化气氛较适用于1000℃以下固硫;高温取Ca/S比为2.0~2.5时较适合;按一定比例添加Fe2O3、SiO2和Al2O3配置的复合脱硫剂脱硫效率更高(试验值66.67%),复合添加剂能提高1000℃以上的固硫率,加宽了最佳固硫温度范围,且能维持比较稳定的高温固硫效果;不同条件下,CaSO4分解特性不同。 相似文献
644.
Wichmann H Sprenger R Ehlers N Bahadir MA 《Environmental science and pollution research international》2005,12(4):227-232
Background, Aims and Scope Releasing agents, applied in the aluminium diecasting process, usually consist of water, oils, waxes, polysiloxanes, as well
as of a set of additives like emulsifiers, corrosion inhibitors, and biocides. During spray application and part release,
gases and aerosols are emitted into workplace air. The chemical compositions of these emissions are determined by the components
of the releasing agents and their reaction products formed during thermal stress of more than 700 °C. In the frame of the
joint project, the analytical tasks were to develop an appropriate sampling strategy for this production environment, to draw
conclusions about the occurrence of hazardous chemicals from production plant studies and from laboratory-scale thermolysis
experiments, and to determine the biodegradability of customary releasing agents.
Methods During realistic test production, active air sampling was performed in a production hall using different adsorption materials.
Cotton fabric sheets were positioned in the production area as passive samplers. Thermolysis experiments were performed at
600 °C with sealed quartz ampoules. The biodegradability of different releasing agents was determined according to German
industry standard DIN 51828 (2000). For analyses, GC/MS (headspace), FTIR, HPLC, IC, and ICP-OES techniques were applied.
Results and Discussion The substance spectrum, which was found in workplace air, was dominated by saturated and non-saturated aliphatic hydrocarbons.
Besides these, alcohols, alkyl phenols, xylenes and other benzene derivatives, aldehydes, glycols, carboxylic acid esters,
and amides were present. The German limiting value of 40 mg/m3 of complex hydrocarbon mixtures in a diecasting workplace atmosphere
was clearly under-run. Total hydrocarbon contents ranged between 2.7 and 6.3 mg/m3. Five different PAH were found in the air
close to the diecasting machine, with maximum concentrations between 0.05 and 3.06 μg/m3. Concentrations of nonylphenols ranged
from 10 to 200 μg/m3, and those of triethanolamine from 20 to 30 μg/m3. From 17 elements analyzed, only B, Fe, P, S, Si, and
Ti were emitted in small amounts. It was striking that the PAH patterns resulting from thermolysis experiments were quite
the same compared to those determined during the diecasting process. An influence of water and of Fe/Al on the composition
of the thermolysis products could mostly be shown. The degrees of biodegradation of three releasing agent extracts after 21
days were 21%, 29%, and 55%, respectively.
Conclusion A sampling strategy was developed, which allows an emission assessment for the industrial process of aluminium diecasting.
It enabled one to control limiting values, to characterise a wide variety of compounds emitted, and to identify and quantify
relevant pollutants. Only a few hazardous substances could be detected during the exemplary use of one releasing agent within
the compounds emitted into workplace air. Indications were found, that the prediction of the formation of harmful substances
from releasing agent components should be possible via thermolysis experiments. The biodegradability test can serve to assess
the expenditure of disposal of the usual leakage run-off of excess agent during production.
Recommendation and Outlook Investigations on further differently composed releasing agents, e.g. powders, would be desirable. A substitution of nonylphenol
ethoxylates by less harmful components would surely be an improvement of a releasing agent with regard to work safety and
health care, because of avoiding the emission of toxic and endocrine active nonylphenols. The surprisingly wide range of biodegradability
of the investigated releasing agents points to an optimization potential, that has obviously not yet been considered. 相似文献
645.
646.
Two-dimensional chamber studies were conducted to determine qualitative and quantitative performance of cosolvents targeted at pooled dense non-aqueous phase liquid (DNAPL) (perchlorethylene, PCE) residing above a fine-grain capillary barrier. Downward mobilization of DNAPL, up gradient along an overriding cosolvent front, was observed. This produced significant pooling above a fine-grain layer that in some cases lead to entry into the capillary barrier beneath. Entry pressure calculations using physical and hydrogeologic parameters provided an excellent prediction of breakthrough of DNAPL into the capillary barrier. Calculations predict approximately 0.5 m of DNAPL would be necessary to enter a Beit Netofa clay, under extreme cosolvent flooding conditions (100% ethanol). Gradient injection of cosolvent did not appear to provide any benefit suggesting a rapid decrease in interfacial tension (IFT) compared to the rate of DNAPL solubilization. Use of a partitioning alcohol (tertiary butyl alcohol, TBA) resulted in DNAPL swelling and reduced entry into the capillary barrier. However, the trapping of flushing solution, containing PCE, could potentially lead to longer remediation times. 相似文献
647.
648.
几种渗透剂对阿维菌素的增效作用 总被引:4,自引:0,他引:4
采用甘蓝叶表法对5种渗透剂进行了筛选,在此基础上,采用幼虫浸渍法和叶片药膜法测定了JFC-2、TX-10和FP-T等3种渗透效果较好的渗透剂对阿维菌素的增效作用,及它们分别与阿维菌素混配后对甘蓝叶片渗透量的影响.结果表明,当阿维菌素药液中含有渗透剂的浓度分别为50、100、200mg/L时,渗透剂JFC-2对阿维菌素浸渍法毒力的增效比分别为1.54、1.74和2.16,叶片药膜法毒力的增效比分别为1.60、1.90和2.18;TX-10的浸渍法毒力增效比分别为1.47、1.70和1.97,叶片药膜法毒力的增效比分别为1.48、1.63和2.00;FP-T的浸渍法毒力增效比分别为1.56、1.59和1.78,叶片药膜法毒力的增效比分别为1.58、1.52和1.86;同时,上述3种渗透剂还可提高阿维菌素对甘蓝叶片的渗透速度,缩短渗透时间.图1表3参11 相似文献
649.
Laan D. van der Tongeren O. F. R. van Putten W. H. van der Veenbaas G. 《Journal of Coastal Conservation》1997,3(1):179-190
In coastal foredunes marram grass (Ammophila arenaria) is used to stabilize windblown sand. The development of traditionally plantedAmmophila into a more natural foredune vegetation may take 5–10 yr. For economic reasons, traditional planting may be replaced by alternative
techniques such as planting seeds or disk-harrowing rhizome fragments. In this paper, we compare the initial vegetation development
of traditionally planted stands with stands established from seeds and from rhizomes.
The experiments were conducted on an artificial foredune originating from dredged sea sand. The total experimental area covered
more than 100 ha and the vegetation development was studied for 6 yr. The data were analysed bya priori grouping of plant species according to their ecology, as well as by Principal Components Analysis (PCA) and Redundancy Analysis
(RA) of the percentage ground cover per plant species.
Comparing ecological groups of plants showed that all planting methods delivered equal numbers of plant species that are indicative
for coastal dunes. PCA and RA showed that methods based on the use of rhizome material resulted in a higher percentage cover
of clonal perennials (Calammophila baltica, Festuca rubra ssp.arenaria, Carex arenaria andCirsium arvense) than the traditionally planted stands and the stands obtained from seeds. The latter two were characterized by the dominance
of annuals, bi-annuals and (mostly nonrhizomatous) perennials.
Initially, the rates of succession were highest in the stands obtained from rhizomes. However, after 3–6 yr there were no
differences between the various stands. During the first four years, the percentage cover by rhizomatous foredune plants developed
faster than that of annuals, bi-annuals and perennials. After 6 yr, the latter contributed almost as much to the percentage
cover as the clonal species. 相似文献
650.
本文就XH-1型大孔吸附树脂对含酚废水处理性能进行了研究,探索了吸附平衡时间,确立了吸附体系Freundlich等温式,找到了树脂在不同再生剂中最佳工艺条件,发现了吸附、脱附过程分别具有二级和一级反应动力学特征,并得到其表现活化能. 相似文献