Nanoscale zero valent iron particles (NZVI) are studied for the treatment of contaminated groundwater. Thanks to their small size, they can be suspended in aqueous slurries and delivered into the subsurface for a targeted treatment of contamination plumes and sources. However, for a successful field-scale application of the technology, a detailed knowledge of NZVI transport mechanism is required, for a prediction of injection radius of influence, and for the design of efficient injection strategies. In particular, a critical aspect for the transport in porous media is related to colloidal stability: zero-valent iron nanoparticles dispersed in pure water do not form stable suspensions, due to fast aggregation and sedimentation, which consequently result in limited travel distances, pore plugging and significant loss of porosity and permeability during injection. Colloidal stability of NZVI was improved using anionic surface chargers or polymeric surface modifiers, to increase particle-particle repulsion by modifying the NZVI surface, or by increasing viscosity of the suspension. Another approach consists in the modification of the particle surface during synthesis by addition of noble metals. Bi-metallic particles in many cases show an increased colloidal stability, along with higher degradation rates towards contaminants. In this study, the mobility of highly concentrated bimetallic Fe/Cu nanoparticles (d50= 70±5 nm) in sand-packed columns was studied. In particular, the influence of injected particle concentrations (8 and 12 g/l) was addressed. Breakthrough curves and water pressure drop along the column, averaged effective porosity and final distribution of retained particles along the column were measured. The experimental data were modelled numerically using the E-MNM1D software.

Numerical Modelling of One-Dimensional Transport and Retention of Highly Concentrated suspensions of Nano-Fe/Cu Particles / Tosco, TIZIANA ANNA ELISABETTA; Hosseini, S. M.. - ELETTRONICO. - (2013). (Intervento presentato al convegno 5th International Conference on Porous Media tenutosi a Prague nel 22-24 May 2013).

Numerical Modelling of One-Dimensional Transport and Retention of Highly Concentrated suspensions of Nano-Fe/Cu Particles

TOSCO, TIZIANA ANNA ELISABETTA;
2013

Abstract

Nanoscale zero valent iron particles (NZVI) are studied for the treatment of contaminated groundwater. Thanks to their small size, they can be suspended in aqueous slurries and delivered into the subsurface for a targeted treatment of contamination plumes and sources. However, for a successful field-scale application of the technology, a detailed knowledge of NZVI transport mechanism is required, for a prediction of injection radius of influence, and for the design of efficient injection strategies. In particular, a critical aspect for the transport in porous media is related to colloidal stability: zero-valent iron nanoparticles dispersed in pure water do not form stable suspensions, due to fast aggregation and sedimentation, which consequently result in limited travel distances, pore plugging and significant loss of porosity and permeability during injection. Colloidal stability of NZVI was improved using anionic surface chargers or polymeric surface modifiers, to increase particle-particle repulsion by modifying the NZVI surface, or by increasing viscosity of the suspension. Another approach consists in the modification of the particle surface during synthesis by addition of noble metals. Bi-metallic particles in many cases show an increased colloidal stability, along with higher degradation rates towards contaminants. In this study, the mobility of highly concentrated bimetallic Fe/Cu nanoparticles (d50= 70±5 nm) in sand-packed columns was studied. In particular, the influence of injected particle concentrations (8 and 12 g/l) was addressed. Breakthrough curves and water pressure drop along the column, averaged effective porosity and final distribution of retained particles along the column were measured. The experimental data were modelled numerically using the E-MNM1D software.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2508520
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