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Studies from J. Buha et al Have Provided New Data on Environmental Science and Technology

June 20, 2014

By a News Reporter-Staff News Editor at Ecology, Environment & Conservation -- Researchers detail new data in Environmental Science and Technology. According to news reporting out of St. Gallen, Switzerland, by VerticalNews editors, research stated, "Waste incineration had been identified as an important source of ultrafine air pollutants resulting in elaborated treatment systems for exhaust air. Nowadays, these systems are able to remove almost all ultrafine particles."

Our news journalists obtained a quote from the research, "However, the fate of ultrafine particles caught in the filters has received little attention so far. Based on the use of engineered nano-objects (ENO) and their transfer into the waste stream, it can be expected that not only combustion generated nanoparticles are found in fly ashes but that many ENO finally end up in this matrix. A more detailed characterization of the nanoparticulate fraction of fly ashes is therefore needed. Physical and chemical characterizations were performed for fly ashes from five selected waste incineration plants (WIPs) with different input materials such as municipal waste, wood and sewage sludge. The intrinsic densities of the fly ashes were in the range of 2.7-3.2 g/cm(3). When the fly ash particle became airborne, the effective density depended on the particle size, increasing from 0.7-0.8 mu g/cm(3) for 100-150 nm to 2 g/cm(3) for 350-500 nm. The fly ash samples were fractionated at 2 mu m, yielding fine fractions (2 mu m). The size distributions of the fine fractions in the airborne form were further characterized, which allowed calculation of the percentage of the fly ash particles below 100 nm. We found the highest mass-based percentage was about 0.07%; the number percentage in the fine fraction was in the range of 4.8% to 22%. Comparison with modeling results showed that ENO may constitute a considerable part of the fly ash particles below 100 nm. Chemical analyses showed that for the municipal waste samples Ca and Al were present in higher concentrations in the coarse fraction; for the mixed wood and sludge sample the P concentration was higher in the coarse fraction; for most other samples and elements they were enriched in the fine fraction. Electron microscopic images of fly ashes showed a wide range of particle sizes, from nanometer range to micrometer range."

According to the news editors, the research concluded: "Many aggregated particles were observed, demonstrating that ENO, bulk-derived nano-objects and combustion-generated nano-objects can form aggregates in the incineration process."

For more information on this research see: Physical and Chemical Characterization of Fly Ashes from Swiss Waste Incineration Plants and Determination of the Ash Fraction in the Nanometer Range. Environmental Science & Technology, 2014;48(9):4765-4773. Environmental Science & Technology can be contacted at: Amer Chemical Soc, 1155 16TH St, NW, Washington, DC 20036, USA. (American Chemical Society -; Environmental Science & Technology -

Our news journalists report that additional information may be obtained by contacting J. Buha, Empa Swiss Fed Labs Mat Sci & Technol, Technol & Soc Lab, CH-9014 St Gallen, Switzerland. Additional authors for this research include N. Mueller, B. Nowack, A. Ulrich, S. Losert and J. Wang.

Keywords for this news article include: Europe, St. Gallen, Switzerland, Environmental Science and Technology

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Source: Ecology, Environment & Conservation

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