Advanced Nanoremediation: Stabilization and Transport Control of Iron Nanoparticles for Contaminant Treatment

Nanoremediation involves the injection of reactive nanomaterials into the subsurface to promote the in situ degradation of pollutants. This technique is emerging as a promising alternative to conventional remediation methods, such as Pump & Treat, Permeable Reactive Barriers, aiir sparging, etc. Due to their nanoscale size, iron-based nanoparticles—such as zero-valent iron (nZVI) and iron oxides—exhibit high reactivity and can create reactive zones capable of treating a wide range of contaminants near their source. However, despite their efficacy in laboratory-scale degradation tests, the application of iron-based micro- and nanoparticles at the field scale remains challenging. Specifically, zero-valent iron particles tend to have limited mobility due to agglomeration caused by magnetic interactions, whereas iron oxides can be overly mobile, leading to the unintended dispersion of reactive material and bypassing the contamination zones.

This presentation will address two key approaches to overcome these limitations. First, we explore the use of green biopolymers to achieve both kinetic and electrosteric stabilization of zero-valent iron nanoparticles, enabling the formulation of highly stable and injectable nanofluids. Second, we introduce a patented strategy for tuning the mobility of iron oxides to precisely target contamination sources while minimizing their dispersion in the subsurface. These approaches are optimized using a hybrid experimental and modeling framework, with upscaled models serving as valuable tools for the design of field-scale applications.

Finally, we will present an innovative and patented in situ synthesis process that overcomes the mobility issues associated with conventional nanoremediation by generating nanoparticles directly within the contaminated zone thanks to the reaction of liquid precursors injected in the target area. This novel approach represents a significant step forward in enhancing the efficiency and feasibility of nanoremediation for groundwater treatment.