Cesium Speciation in Dust from Municipal Solid Waste and Sewage Sludge Incineration by Synchrotron Radiation Micro-X-ray Analysis

Shiota, Kenji; Takaoka, Masaki; Fujimori, Takashi; Oshita, Kazuyuki; Terada, Yasuko

doi:10.1021/acs.analchem.5b03298

Cited by 28 publications

(21 citation statements)

References 23 publications

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“…Current knowledge on the behavior of r-Cs or stable Cs in MSWI and SSI is as follows: more than half of the r-Cs 9 and stable Cs 22 in MSW were distributed to fly ash (MSWI-FA) in stoker incineration plants. The chemical form of Cs in MSWI-FA was identified as mostly chlorides 9,10,12,16 or at least water-soluble forms. 13−16 According to the analyses of the residues of co-incineration of MSW and Cs 2 CO 3 reagent, 11,12 Cs in the MSW bottom ash (MSWI-BA) was mostly glassy materials or metal sulfides or crystalline aluminosilicates such as pollucite, except for the unchanged reagents.…”

Section: Introductionmentioning

confidence: 99%

“…9,13,14 In sewage sludge incineration (SSI) using a fluidized-bed incinerator, r-Cs in the SSI-fly ash (SSI-FA) was mostly water-insoluble. 13,14,17−21 The chemical forms of r-Cs in the SSI-FA have not yet been directly determined, but are suggested as aluminosilicate 10 or part of the oxides including iron. 19 Some studies have reported that in highly alkaline solution (pH > 12) 18 or in acidic solutions, 17,19 leachability of the r-Cs from the SSI-FA increased greatly.…”

Section: Introductionmentioning

confidence: 99%

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Understanding the Behavior of Radioactive Cesium during the Incineration of Contaminated Municipal Solid Waste and Sewage Sludge by Thermodynamic Equilibrium Calculation

2018

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Following the nuclear accident at the Fukushima Daiichi Nuclear Power Plant in 2011, even the municipal solid waste (MSW) and sewage sludge (SS) in northeastern Japan became contaminated by radioactive nuclides such as 137 Cs and 134 Cs. To understand the state of radioactive cesium (r-Cs) in the incineration residues of the municipal wastes, research groups studied the concentration and the chemical form of r-Cs in the residues, as well as its water-leaching behavior. In the present study, we conducted thermodynamic equilibrium calculations to estimate the possible chemical forms of r-Cs in the incineration residues. Thermodynamic data for cesium oxides and aluminosilicates were collected and compiled into a new database to perform equilibrium calculations for systems that include Cs. The calculation results suggested that Cs (radiocesium and stable cesium) in municipal solid waste was transformed into gaseous CsCl or crystalline aluminosilicate at incineration temperatures and, when a molten aluminosilicate phase (i.e., slag phase) was generated, a proportion of the Cs species was dissolved into the slag phase. In the case of sewage sludge, Cs was calculated to be transformed mostly into crystalline aluminosilicate at incineration temperatures, whereas by analogy with the behaviors of Na and K, Ca,Cs-phosphate double salts were also potential incineration products. These results could account for the high leaching rates of r-Cs from the MSW incineration fly ash and the low leaching rates from the MSW incineration bottom ash and SS incineration fly ash reported in earlier studies. In the case of dewatered SS that included a large amount of slaked lime as a flocculant, it was exceptionally difficult for the calculation to represent the fate of Cs, and we needed to include the contribution of silica sand in a fluidized-bed combustor in the equilibrium calculation to represent the low leaching rates of alkali species from the dewatered SS fly ash. From the results of the thermodynamic equilibrium calculations and also from the calculated standard Gibbs energy of cesium aluminosilicate formation/decomposition reactions, the effects of waste composition and incineration temperature on the fate of Cs were examined: High incineration temperature and large amounts of Ca and Cl in the waste composition increased the fraction of gaseous CsCl in the furnace and thus resulted in the high distribution ratios of Cs in the fly ash of MSW and the high leaching rates of Cs from the fly ash.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Understanding the Behavior of Radioactive Cesium during the Incineration of Contaminated Municipal Solid Waste and Sewage Sludge by Thermodynamic Equilibrium Calculation

2018

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“…Cs is known to be a volatile element [15]. In addition, the Cs present in BA and FA exists in different forms [11,[16][17][18]. This is because most r-Cs enters municipal solid waste (MSW) incineration facilities via vegetation and soil and is volatilized into a gaseous state during incineration, following which it migrates into the flue gas [19].…”

Section: Elemental Composition Of Ash Samplesmentioning

confidence: 99%

“…The r-Cs cools near the baghouse filter, which is controlled at a temperature of approximately 200 • C. The r-Cs then solidifies and concentrates in the FA. Therefore, Cs may exist in FA in the form of highly water-soluble CsCl [8,17,18], CsOH, and Cs 2 SO 4 [20,21].…”

Section: Elemental Composition Of Ash Samplesmentioning

confidence: 99%

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Characterising Radioactive Caesium Leaching from Incineration Ash of Municipal Solid Waste in Fukushima and the Inhibitory Effect of Acid Clay

Murasawa

2021

Recycling

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Following the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident caused by the 2011 Tōhoku earthquake and tsunami, radioactive caesium (r-Cs) was detected in the ash generated by municipal solid waste (MSW) incineration facilities in Fukushima Prefecture. This has led to concerns of r-Cs leaching and subsequent environmental contamination during recycling or landfill disposal. Therefore, it is crucial that the relevant authorities have a thorough understanding of r-Cs leaching behavior to establish suitable prevention methods. In this study, we collected r-Cs-contaminated fly and bottom ash (FA and BA) samples from five MSW incineration facilities in Fukushima Prefecture and conducted tests to clarify their basic physical properties and r-Cs leaching properties. We also examined the possibility of preventing r-Cs leaching by adding 5 wt% acid clay to the FA. FA had greater chloride content and r-Cs leaching rate than BA and was found to absorb moisture and deliquesce when stored under high-humidity conditions. However, the addition of acid clay effectively prevented r-Cs leaching upon contact with moisture. From the results, we propose some specific recommendations to counter the leaching of r-Cs from FA at MSW incineration facilities, which will limit r-Cs leaching during recycling or landfill processes.

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Interaction of biochar with extracellular polymers of resistant bacteria restrains Pb(II) adsorption onto their composite: Macro and micro scale investigations

Wang,

Chen,

Han

et al. 2024

Bioresource Technology

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Cesium Speciation in Dust from Municipal Solid Waste and Sewage Sludge Incineration by Synchrotron Radiation Micro-X-ray Analysis

Cited by 28 publications

References 23 publications

Understanding the Behavior of Radioactive Cesium during the Incineration of Contaminated Municipal Solid Waste and Sewage Sludge by Thermodynamic Equilibrium Calculation

Understanding the Behavior of Radioactive Cesium during the Incineration of Contaminated Municipal Solid Waste and Sewage Sludge by Thermodynamic Equilibrium Calculation

Characterising Radioactive Caesium Leaching from Incineration Ash of Municipal Solid Waste in Fukushima and the Inhibitory Effect of Acid Clay

Interaction of biochar with extracellular polymers of resistant bacteria restrains Pb(II) adsorption onto their composite: Macro and micro scale investigations

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