Groundwater Remediation Technologies with Zero-Valent Iron

Groundwater remediation using zero-valent iron (Fe0) exploits the metal’s strong reducing potential and the sorptive properties of its corrosion products to remove a broad spectrum of inorganic and organic contaminants. In situ approaches commonly employ permeable reactive barriers (PRBs) filled with granular or filings-grade iron, enabling passive treatment of plumes without continuous maintenance or energy inputs. Ex situ strategies include fluidised bed reactors and fixed-bed filters that provide controlled flow regimes to maximise contact between water and iron surfaces. Nanoscale zero-valent iron (nZVI) particles offer enhanced reactivity and subsurface mobility but present challenges such as rapid agglomeration, limited longevity and potential ecotoxicity. Across scales, the dominant removal mechanisms encompass reductive transformation of chlorinated solvents and oxyanions, co-precipitation of metals within iron hydroxides, and adsorption onto evolving iron oxides. Key practical considerations include the prevention of pore clogging by corrosion products, maintenance of hydraulic conductivity, and characterisation of Fe0 intrinsic reactivity to inform sustainable design. Collectively, these technologies have global significance in addressing contamination by chlorinated solvents, heavy metals and emerging organic pollutants, offering low-cost and scalable solutions for both rural and industrial settings.

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Groundwater Remediation Technologies with Zero-Valent Iron publication trend

The graph below shows the total number of articles in groundwater remediation technologies with zero-valent iron across all publications each year (not limited to Nature Index journals).

Technical terms

Zero-Valent Iron (ZVI): Elemental iron (Fe0) used as a reductant and sorbent for contaminant removal in water treatment.

Permeable Reactive Barrier (PRB): An in situ subsurface treatment zone filled with reactive media, such as granular iron, through which contaminated groundwater passes and is remediated.

Nanoscale Zero-Valent Iron (nZVI): Ultra-fine Fe0 particles (<100 nm) with high surface area and reactivity, designed for injection into contaminated aquifers.

Co-precipitation: The simultaneous precipitation of contaminants with iron corrosion products, leading to stable incorporation within iron hydroxides.

Hydraulic Conductivity: A measure of a porous medium’s ability to transmit water, critical for ensuring effective flow through Fe0 filters or barriers.

References

1. Materials for sustainable metallic iron-based water filters: a review. Environmental Chemistry Letters (2024).
2. Review: The fundamental mechanism of aqueous contaminant removal by metallic iron. Water SA (2010).
3. Arsenic removal with zero-valent iron filters in Burkina Faso: Field and laboratory insights. The Science of The Total Environment (2020).
4. Application and development of zero-valent iron (ZVI) for groundwater and wastewater treatment. International Journal of Environmental Science and Technology (2022).