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791.
792.
A new iron-fly ash packing was studied for reductive transformation of p-nitrotoluene. The packing was made of iron, fly ash and kaolin with the mass ratio of 36:7:2. A reactor was designed to investigate the long-term performance of the packing. The results showed that the reduction of p-nitrotoluene increased with decreasing pH, because the reduction potential of reaction increased with the concentration of H+. The pH was one of the key factors impacting the reductive transformation of p-nitrotoluene. Comparing iron-activated carbon packing with the new iron-fly ash packing, the reduction efficiencies were respectively 76.61% and 75.36% after 20 days. The reduction efficiency for both was around 50% at 40 days. It was evident that these two kinds of packing had no significant difference in their capability for p-nitrotoluene reductive transformation. Compared with iron-activated carbon, the new iron-fly ash packing had obvious advantages in terms of manufacturing costs and environmental pollution degradation. This study showed that the new iron-fly ash packing had good performance in reductive transformation of nitrotoluene compounds. 相似文献
793.
Natalya Irha 《毒物与环境化学》2013,95(1-2):105-110
The aim of this work was to estimate the sorption of pyrene from water solutions on mineral substrates, e.g., alumina, silica, and oil shale ash, from the Estonian thermal plant. Results obtained from this study indicate that the sorption of pyrene on mineral oxides and oil shale ash particles from water can be described with a linear equation. The sorptive capacity per weight of oil shale ash in aqueous systems was significantly lower compared with mineral adsorbents. The distribution coefficient (Kd) for pyrene in the system with particles of oil shale ash was 10–12 times lower as than for mineral adsorbents. 相似文献
794.
Coal fly ash (CFA) is dumped at a deep sea disposal site (1,500m water depth) in the eastern Mediterranean, ca. 70km off the Israeli shore. Since 1989, about one million tons of CFA were dumped at the 200km2 allocated area. Six years of monitoring at the dump-site shows that the CFA is heterogeneously distributed; there are areas where CFA covers about 1.3cm depth of the sea floor while at others no CFA is found. CFA is present as a fine powder, small aggregates and even as large blocks both in the dump-site as well as at its peripheries. Cadmium, copper and zinc concentrations in the CFA decreased as a result of the prolonged contact with sea water at in situ conditions while inconclusive changes in mercury, iron and manganese were detected. No changes were observed for lead, iron and aluminium concentrations. A controlled long term field experiment, now in progress at the site, is expected to clarify further chemical changes occurring in the CFA. 相似文献
795.
《International Journal of Sustainable Engineering》2013,6(3):211-218
Alkali ash material (AAM) concrete is a unique material that is sustainable and cost-effective because it utilises waste fly ash, and has properties superior to other concrete products. The AAM concrete described here is produced from the addition of inexpensive chemicals to fly ash. AAM can be used to create a wide range of materials including high performance concrete (HPC-AAM) and lightweight (LW-AAM). The high performance AAM provides rapid strength gain along with high ultimate strengths of more than 110 MPa (16000 psi). LW-AAM can produce materials with densities ranging from 1200 to 2200 kg/m3 and compressive strengths from 2 (290 psi) to 65 MPa (9500 psi). Both HPC-AAM and LW-AAM have far better environmental resistance than Portland cement concrete, resisting attack from sulphuric acid (H2SO4), hydrochloric acid (HCl) and organic acids. AAMs resists freeze–thaw attack and high abrasion, possesses low chloride permeability and does not exhibit alkali silica reactivity. 相似文献
796.
本文从微珠、粉煤灰和粘土相近的化学成分出发 ,分析了混合料的结合和反应机理 ,在这个基础上研究了各种配方情况下的保温砖的成型工艺 ,指出烧结法工艺品有良好的性能 ,掺入较多的粉煤灰将有更好的环境效益和经济效益。为了简化工艺 ,节约能源 ,便于推广 ,初步研究了用化学方法粘结的非烧结工艺———这是一种有前途的保温砖成型工艺。 相似文献
797.
Michael E. Boesch Carl Vadenbo Dominik Saner Christoph Huter Stefanie Hellweg 《Waste management (New York, N.Y.)》2014,34(2):378-389
A process model of municipal solid waste incinerators (MSWIs) and new technologies for metal recovery from combustion residues was developed. The environmental impact is modeled as a function of waste composition as well as waste treatment and material recovery technologies. The model includes combustion with a grate incinerator, several flue gas treatment technologies, electricity and steam production from waste heat recovery, metal recovery from slag and fly ash, and landfilling of residues and can be tailored to specific plants and sites (software tools can be downloaded free of charge). Application of the model to Switzerland shows that the treatment of one tonne of municipal solid waste results on average in 425 kg CO2-eq. generated in the incineration process, and 54 kg CO2-eq. accrue in upstream processes such as waste transport and the production of operating materials. Downstream processes, i.e. residue disposal, generates 5 kg CO2-eq. Savings from energy recovery are in the range of 67 to 752 kg CO2-eq. depending on the assumptions regarding the substituted energy production, while the recovery of metals from slag and fly ash currently results in a net saving of approximately 35 kg CO2-eq. A similar impact pattern is observed when assessing the MSWI model for aggregated environmental impacts (ReCiPe) and for non-renewable resource consumption (cumulative exergy demand), except that direct emissions have less and no relevance, respectively, on the total score. The study illustrates that MSWI plants can be an important element of industrial ecology as they provide waste disposal services and can help to close material and energetic cycles. 相似文献
798.
799.
T. A. Pristova 《Russian Journal of Ecology》2008,39(3):176-182
The biological turnover of nitrogen and ash elements has been studied in a secondary deciduous-coniferous stand formed in place of a clear-cut spruce forest. The results have shown that a high degree of accumulation is characteristic of Ca, N, K, and Si, with N, Ca, K, Si, P, and Mg being most actively involved in the biological turnover. The biological turnover in this stand is of the calcium-nitrogen-potassium type, and its intensity and rate exceed those in bilberry spruce forest by factors of 1.7 and 2–4, respectively. 相似文献
800.
关于钨冶炼收尘装置的研究 总被引:1,自引:0,他引:1
本文是关心钨冶炼收尘装置的研究,文章主要就钨精矿焙烧的收尘问题提出了一种新的收尘设备,使钨精矿焙烧的收尘效率达到99%。 相似文献