The implication of iron oxide nanoparticles on the removal of trichloroethylene by adsorption

The fate and transport of Fe2O3 NPs in a granular activated carbon (GAC) adsorber and its impact on the removal of trichloroethylene (TCE) by GAC was investigated. The hydrodynamic diameter of Fe2O3 NPs was measured with time to evaluate their aggregation potential. Specific surface area (SSA) and zeta potential were obtained for Fe2O3 NPs and GAC in order to understand their interaction. The impact of Fe2O3 NPs on TCE adsorption was tested by conducting TCE adsorption isotherms, kinetics and column breakthrough studies in the presence and absence of Fe2O3 NPs. SSA and pore size distribution of the fresh and the spent GAC were obtained. The fate and transport of the Fe2O3 NPs in the GAC fixed bed and their impact on TCE adsorption was found to be a function of their zeta potential, concentration, and size. Fe2O3 NPs formed larger aggregates in water. These aggregates attached to GAC and reduced the amount of TCE adsorbed during the breakthrough experiments suggesting a preloading pore blockage phenomenon. Pore blockage and SSA reduction occured on the used GAC. However, due to the fast adsorption kinetics of TCE no effect of Fe2O3 NPs was observed in the isotherm and the kinetic studies. TCE adsorption onto the Fe2O3 NPs was found to take place over a short period of time.

► Fe2O3 NPs effect is a function of their zeta potential, concentration and size.
► Breakthrough studies showed adsorbent pore blockage and surface area reduction.
► The adsorption isotherms suggest weak attachment of Fe2O3 NPs.
► The isotherm results could falsely predict dynamic breakthrough.
► The experimental breakthrough studies confirm the implications of NPs.