https://doi.org/10.1140/epjst/e2015-02512-x
Review
Nanoporous clay with carbon sink and pesticide trapping properties
1 Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), UMR CNRS 7263, Aix Marseille Université, 13331 Marseille Cedex 03, France
2 Campus Agro Environnemental Caraïbes -IMBE- UMR IRD 237, BP. 214, Petit Morne, 97232 Le Lamentin, Martinique
3 PRIME Verre, PAT du Millénaire Bât. 10, 1350 avenue A. Einstein, Montpellier, France
4 Laboratoire Charles Coulomb UMR 5221 CNRS-UM2, Université Montpellier 2, 34095 Montpellier Cedex 5, France
a e-mail: thierry.woignier@imbe.fr
Received: 6 November 2014
Revised: 21 May 2015
Published online: 30 July 2015
A thorough understanding of the mechanisms and factors involved in the dynamics of organic carbon in soils is required to identify and enhance natural sinks for greenhouse gases. Some tropical soils, such as Andosols, have 3–6 fold higher concentrations of organic carbon than other kinds of soils containing classical clays. In the tropics, toxic pesticides permanently pollute soils and contaminate crops, water resources, and ecosystems. However, not all soils are equal in terms of pesticide contamination or in their ability to transfer pollution to the ecosystem. Andosols are generally more polluted than the other kinds of soils but, surprisingly, they retain and trap more pesticides, thereby reducing the transfer of pesticides to ecosystems, water resources, and crops. Andosols thus have interesting environmental properties in terms of soil carbon sequestration and pesticide retention. Andosols contain a nano porous clay (allophane) with unique structures and physical properties compared to more common clays; these are large pore volume, specific surface area, and a tortuous and fractal porous arrangement. The purpose of this mini review is to discuss the importance of the allophane fractal microstructure for carbon sequestration and pesticide trapping in the soil. We suggest that the tortuous microstructure (which resembles a labyrinths) of allophane aggregates and the associated low accessibility partly explain the poor availability of soil organic matter and of any pesticides trapped in andosols.
© EDP Sciences, Springer-Verlag, 2015
