2 results
Interactions of Radioactive and Stable Cesium with Hydroxy-Interlayered Vermiculite Grains in Soils of the Savannah River Site, South Carolina, USA
- Momoko Goto, Robert Rosson, W. Crawford Elliott, J. M. Wampler, Steven Serkiz, Bernd Kahn
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- Journal:
- Clays and Clay Minerals / Volume 62 / Issue 3 / June 2014
- Published online by Cambridge University Press:
- 01 January 2024, pp. 161-173
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- Article
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Sorption and fixation of Cs by the upland soils of the US Department of Energy’s Savannah River Site (SRS) have been attributed to micaceous grains consisting mostly of hydroxy-interlayered vermiculite (HIV). Results of experiments to characterize SRS soil samples, to examine aspects of their radiocesium sorption, and to determine how much of their natural Cs is accessible for chemical extraction and isotope dilution are presented in support of mechanistic hypotheses to explain Cs sorption and fixation in HIV grains. The HIV is responsible for most of the soil cation exchange capacity, and concentrations of naturally occurring Cs, Rb, and K in soil samples are closely related to the concentration of HIV. Experiments with 137Cs to examine (1) sorption kinetics, (2) blocking of exchange sites with silver thiourea, and (3) susceptibility of sorbed 137Cs to chemical extraction, support the idea that added Cs is sorbed at different kinds of cation exchange sites in HIV grains. Sites highly selective for Cs but relatively few in number are inferred to exist in interlayer wedge zones within such grains. Little of the naturally occurring Cs in the soil samples was extractable by chemical agents that would remove Cs from ordinary cation-exchange sites and from within non-silicate soil components. Furthermore, most of the natural Cs was inaccessible for isotope dilution under slightly acidic conditions approximating the natural soil environment. These observations support the idea that most of the Cs in these soils has become effectively fixed in the narrower parts of interlayer wedge zones. Control of Cs uptake and fixation by highly Csselective interlayer wedge sites would account for the large distribution coefficients found for 137Cs at the low aqueous Cs concentrations typical of environmental systems and also for the relatively large concentrations of stable Cs in the SRS soils.
Chapter 2 - Bioenergy
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- By Helena Chum, Andre Faaij, José Moreira, Göran Berndes, Parveen Dhamija, Hongmin Dong, Benoît Gabrielle, Alison Goss Eng, Wolfgang Lucht, Maxwell Mapako, Omar Masera Cerutti, Terry McIntyre, Tomoaki Minowa, Kim Pingoud, Richard Bain, Ranyee Chiang, David Dawe, Garvin Heath, Martin Junginger, Martin Patel, Joyce Yang, Ethan Warner, David Paré, Suzana Kahn Ribeiro
- Edited by Ottmar Edenhofer, Ramón Pichs-Madruga, Youba Sokona, Kristin Seyboth, Susanne Kadner, Timm Zwickel, Patrick Eickemeier, Gerrit Hansen, Steffen Schlömer, Christoph von Stechow, Patrick Matschoss
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- Book:
- Renewable Energy Sources and Climate Change Mitigation
- Published online:
- 05 December 2011
- Print publication:
- 21 November 2011, pp 209-332
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Summary
Executive Summary
Bioenergy has a significant greenhouse gas (GHG) mitigation potential, provided that the resources are developed sustainably and that efficient bioenergy systems are used. Certain current systems and key future options including perennial cropping systems, use of biomass residues and wastes and advanced conversion systems are able to deliver 80 to 90% emission reductions compared to the fossil energy baseline. However, land use conversion and forest management that lead to a loss of carbon stocks (direct) in addition to indirect land use change (d+iLUC) effects can lessen, and in some cases more than neutralize, the net positive GHG mitigation impacts. Impacts of climate change through temperature increases, rainfall pattern changes and increased frequency of extreme events will influence and interact with biomass resource potential. This interaction is still poorly understood, but it is likely to exhibit strong regional differences. Climate change impacts on biomass feedstock production exist but if global temperature rise is limited to less than 2°C compared with the pre-industrial record, it may pose few constraints. Combining adaptation measures with biomass resource production can offer more sustainable opportunities for bioenergy and perennial cropping systems.
Biomass is a primary source of food, fodder and fibre and as a renewable energy (RE) source provided about 10.2% (50.3 EJ) of global total primary energy supply (TPES) in 2008. Traditional use of wood, straws, charcoal, dung and other manures for cooking, space heating and lighting by generally poorer populations in developing countries accounts for about 30.7 EJ, and another 20 to 40% occurs in unaccounted informal sectors including charcoal production and distribution.