Testing the Suitability of Zerovalent Iron Materials for Reactive Walls

Abstract

Environmental Context. Groundwater remediation is generally a costly, long-term process. In situ remediation using permeable reactive barriers, through which the groundwaters pass, is a potential solution. For redox-sensitive contaminants in groundwater, a metallic iron barrier (zerovalent iron, ZVI) can immobilize or degrade these dissolved pollutants. Scrap iron materials are a low-cost ZVI material but, because of the wide variation of scrap metal compositions, testing methods for characterizing the corrosion behaviour need to be developed. Abstract. Zerovalent iron (ZVI) has been proposed as reactive material in permeable in situ walls for contaminated groundwater. An economically feasible ZVI-based reactive wall requires cheap but efficient iron materials. From an uranium treatability study and results of iron dissolution in 0.002 M EDTA by five selected ZVI materials, it is shown that current research and field implementation is not based on a rational selection of application-specific iron metal sources. An experimental procedure is proposed which could enable a better material characterization. This procedure consists of mixing ZVI materials and reactive additives, including contaminant releasing materials (CRMs), in long-term batch experiments and characterizing the contaminant concentration over the time.