Woignier T., Clostre F., Rangon Luc, Lesueur Jannoyer M. (2017). Natural nano materials trapp pollutants in soils. International Journal of Energy and Environment, 11 (art. no a522), p. 160-167. ISSN 2308-1007.
Titre du document
Natural nano materials trapp pollutants in soils
Année de publication
Type de document
Woignier T., Clostre F., Rangon Luc, Lesueur Jannoyer M.
International Journal of Energy and Environment, 2017,
11 (art. no a522), p. 160-167 ISSN 2308-1007
Persistent pesticides led to long term pollution of soils and consequently contaminate rivers, groundwater, ecosystems and finally human beings. Volcanic soils (andosols) are generally more polluted than the other kinds of tropical soils but data show that andosols release less pesticides to percolating water and crops. Andosols contain amorphous clays (allophane) which present unique structures and physical properties compared to crystalline clays. Allophane aggregates have physical features very close to that of nano porous materials like synthetic gels: large pore volume and water content, a broad pore size distribution, a high specific surface area and a fractal structure. The aim of the study was to show the influence of the features (nano materials structure, shrinkage during drying) of these natural gels on the pesticide retention. Our study confirms that the soil to crop pesticide transfer is lower in andosols compared to other volcanic soils. Associated to high organic matter content, the allophane microstructure favor pollutants (chlordecone) accumulation in soils. We put forth the importance of the nano porous features of allophane (the associated tortuous microstructure) but also the pore collapse during drying, for pollutant trapping in soils.