Nanostructured multifunctional materials for environmental remediation of chlorinated hydrocarbons

Spherical silica particles containing nanoscale zero valent iron were synthesized through an aerosol assisted process. These particles are effective for groundwater remediation, with the environmentally benign silica particles serving as effective carriers for nanoiron transport. Incorporation of iron into porous submicron silica particles protects ferromagnetic iron nanoparticles from aggregation and may increase their subsurface mobility. Additionally, the presence of surface silanol groups on silica particles allows control of surface properties via silanol modification using organic functional groups. Aerosolized silica particles with functional alkyl moieties such as ethyl groups on the surface, clearly adsorb solubilized trichloroethylene (TCE) in water. These materials may therefore act as adsorbents which have coupled reactivity characteristics. Transport experiments indicate that these composite particles are in the optimal size range for effective transport through sediments. The nanoscale iron/silica composite particles with controlled surface properties have the potential to be efficiently applied for in-situ source depletion and in the design of permeable reactive barriers.