The application of nanoscale materials in groundwater remediation

Abstract

This review article summarizes the current situation in the application of nanotechnology to contaminated site remediation. Many types of nanomaterials and nanoparticles have been produced since their discovery. As remediation tools, carbon-based nanomaterial (CNM) sorbents and nanoparticles of zero-valent iron (nZVI) are at the forefront of scientific interest. The most often used CNM sorbents are multiwalled and singlewalled carbon nanotubes (MWCNTs and SWCNTs), which are only examined under laboratory conditions. nZVI has already been applied to real contaminated sites as an in situ technology through direct injection into aquifers. CNM sorbents can remove both organic contaminants aliphatic and mono and polycyclic aromatic hydrocarbons and their derivatives, plus inorganic contaminants such as divalent metal ions (Cd2+, Pb2+, Zn2+, Ni2+, Cu2+) from polluted water. Zero-valent iron nanoparticles have been used for the removal of TCE, VOC, nitrates, and uranium. This review shows that these nanomaterials are a promising solution in the field of groundwater remediation, but there are also many unanswered questions regarding the environmental risks of nanoscale materials, which are outlined as well.