Nano-scale Zero Valent Iron (nZVI) Treatment of Marine Sediments Slightly Polluted by Heavy Metals

Abstract

Zero valent iron (ZVI) is an electron donor that is used to reduce or indirectly oxidize several contaminants in soil and groundwater (e.g. halogenated species). The development of stable nano-scale ZVI (nZVI) products has gained a growing interest in environmental remediation with numerous applications all over the world. Several studies addressed both treatment efficiency and ecotoxicological effects of nano-based products for site remediation. However only a few information related to nZVI use for the treatment of marine sediments slightly polluted by heavy metals are available. The present study was aimed at evaluating the effectiveness of nZVI treatment for the decontamination of marine sediments polluted by heavy metals, using the commercial product Nanofer 25s. Two kinds of experiments labelled as (i) sediment at low dosage (2, 3 and 4 g nZVI per kg of SS) and (ii) sediment at high dosage (5, 10 and 20 g nZVI for every kg SS) were performed on sieved sediment with a size < 5 mm. The optimal amount of nZVI to be potentially used for sediment reclamation was identified. According to results, nZVI is more suitable to be used for specific elements removal rather than to be applied for a generalised contamination, meaning that a mix of techniques can be suggested for whole sediment remediation.