Immobilization of selenate by iron in aqueous solution under anoxic conditions and the influence of uranyl

Reduction of selenite and selenate on anoxically corroded iron and the synergistic effect of uranyl reduction

“…Since only about half of the selenate in solution was immobilized, repassivation of the surface appears to occur. The observations in this study agree with our recent findings [23], that reduction of dissolved uranyl by a corroding iron surface greatly increase the reductive immobilization rate and capacity of the surface with regard to other dissolved contaminants such as selenate as well as selenite.…”

“…4). We recently studied the influence of dissolved uranyl on the immobilization of selenate on a polished iron surface and on iron that was precorroded in a uranyl solution (anoxic conditions, similar surface areas, 10 mM NaCl, 2 mM NaHCO 3 ) [23]. In the present study the removal of selenate, and most notably, that of the uranyl is considerably slower.…”

“…As we have recently shown [23], reduction of dissolved uranyl has a strong impact on the immobilization of selenate by an iron surface. In the present study we examine the impact of dissolved uranyl on the immobilization of selenite and selenate by corroded iron surfaces with magnetite layers under simulated anoxic groundwater conditions.…”

Electron transfer during selenium reduction by iron surfaces in aqueous solution: High resolution X-ray absorption study

“…A steel carbon foil was cut inside a glovebox (O 2 level < 0.1 ppm), polished with sand paper and exposed to the ground water with selenate solution for 5.5 months. A second iron sample was pre-corroded in heated water at 90°C and air saturated neutral distilled water for 4 weeks, divided into several small pieces and then exposed to the ground water solution [11]. The selenium concentrations in both solutions were found to be ~ 3 ppm at the start and end of exposure.…”

Reductive removal of selenate by zero-valent iron: The roles of aqueous Fe2+ and corrosion products, and selenate removal mechanisms

“…It has also been proved that ZVI (Yoon et al, 2011;Gibson et al, 2012) or nano-ZVI (Olegario et al, 2010) was effective for Se VI removal from wastewater by reducing to more adsorptive Se IV and/or to insoluble Se species (i.e., Se 0 , Se ÀI and Se ÀII ). However, most of previous studies primarily focused on the effects of co-existent ions, contaminants, and the operational parameters such as pH, dissolved oxygen and reagent concentration (Klas and Kirk, 2013;Puranen et al, 2009). But none of them has clearly illustrated the role and evolution of Fe 2þ during selenate reduction by ZVI.…”