Review of Nanotechnology for Soil and Groundwater Remediation: Brazilian Perspectives

The soil remediation field is still in development in Brazil. Currently, it is not known how many contaminated sites exist across the country; however, due to the country’s large size and its extensive urbanization and industrialization, it can be postulated that the number of contaminated sites must be very high. To remediate these sites, new sustainable technologies should be identified and evaluated. A technology that was born in the 1990s in the USA, and has been fairly investigated, is the use of nanoparticles (NPs) to degrade contaminants in soils and groundwater. This study aims to present a bibliographic review of nanotechnology application to remediation of soils and groundwater, as well as assess the potential of conducting research in this field in Brazil. This paper first presents an overview of the number of contaminated areas identified in the USA and Europe. The basic concepts of nanomaterials followed by classification, synthesis, and characterization of nanomaterials are explained. The main types of contaminants for which the technique was already applied as well as the chemical reactions between them and NPs are presented. The issues related to delivery and migration of NPs in the porous media is discussed. Concerns regarding the toxicity of nanomaterials are discussed. The in situ applications of nanomaterials for contaminated site remediation are presented. It is concluded that the issues involving remediation of soils and groundwater are site specific and it is not possible to directly transfer knowledge gained from sedimentary soils of temperate climates for residual soils found in tropical and subtropical climate regions. The research on nanotechnology for site remediation in Brazil has just begun, and more efforts are required from the technical and academic professionals to develop nanotechnology as practical technology for the remediation of contaminated sites.