Reactivity screening of microscale zerovalent irons and iron sulfides towards different CAHs under standardized experimental conditions

Use of CAH-degrading bacteria as test-organisms for evaluating the impact of fine zerovalent iron particles on the anaerobic subsurface environment

“…TCE concentrations and degradation products were measured over time to provide more details on degradation pathway followed, which is different for reduction by ZVI (predominant b-elimination with acetylene formation) and biodegradation (hydrogenolysis with cDCE and VC formation). Earlier, it was shown that the main degradation pathway for mZVI-1 was b-elimination where cDCE as degradation product does not appear (Velimirovic et al, 2013). Similar behavior was observed for other tested ZVIs (data not shown).…”

“…Although the reactivity of mZVIs and nZVIs in respect to their CAH-removal efficiency has been extensively reported (Velimirovic et al, 2013), studies reporting the impact of mZVIs and nZVIs on the anaerobic subsurface environment are scarce. Selection of representative approaches to evaluate potential ecotoxicity effects of zerovalent iron (ZVI) appears to be challenging as classical single-species toxicity tests (OECD or ISO standard tests) and molecular approaches focus mainly on aerobic aquatic environment (e.g.…”

Review of Abiotic Degradation of Chlorinated Solvents by Reactive Iron Minerals in Aquifers

“…These rate constants were 7.16 × 10 −2 and 2.74 × 10 −2 L/m 2 /day, respectively. Velimirovic et al () found for biogenic FeS, rate constants follow the order of PCE > 1,1,1‐TCA > TCE > DCE. But for reagent FeS from Aldrich, a different reactivity order is shown: 111‐TCA > TCE > PCE > cis ‐DCE.…”

Pressure-controlled injection of guar gum stabilized microscale zerovalent iron for groundwater remediation

“…Several commercially available mZVI particle brands were considered and most of them proved to be able to effectively degrade the afore mentioned chlorinated hydrocarbons under batch conditions, but the finest sample (Carbonyl Iron Powder HQ, BASF, Germany), was chosen in order to reduce particle filtration during the injection. HQ particles are characterized by a fine granulation (d 10 , d 50 , d 90 equal to 0.84, 1.40, 2.29 μm respectively, measured by laser diffraction using a Mastersizer 2000, Malvern, UK), spherical shape, very high purity (iron content in the range of 97-98%) and large specific surface area (Schlicker et al, 2000;Su and Puls, 2004;Velimirovic et al, 2013;Westerhoff, 2003). Nevertheless, HQ particles, if dispersed in pure water, are very unstable and prone to partial aggregation and fast sedimentation, due to their micrometric size, high density (close to bulk iron density of 7.8 g/cm 3 ), and weak attractive forces among particles.…”