Application of surface complexation modeling to the reactivity of iron(II) with nitroaromatic and oxime carbamate contaminants in aqueous TiO2 suspensions

Electrochemical Evidences for Promoted Interfacial Reactions: The Role of Fe(II) Adsorbed onto γ-Al2O3 and TiO2 in Reductive Transformation of 2-Nitrophenol

“…Adsorption studies revealed that modulating pH can significantly change the extent of Fe(II) adsorbed onto different minerals (Figure 1), as increasing pH facilitates surface deprotonation reactions and thus leads to the production of surface-complex Fe(II) (16,17). Our electrochemical studies demonstrated that the measured E P was also highly dependent on pH ( Figure 3).…”

“…A general consensus is that the mineral surface provides hydroxyl groups to stabilize Fe(II), leading to the formation of surface-complex Fe(II) species such as tSOFe + and tSOFeOH 0 with lower redox potential compared to aqueous Fe(II) species. The negative shift of the redox potential proved to be indicative of the enhancement of Fe(II) reactivity (16,17). However, despite the above wellrecognized conclusion, there is a lack of experimental evidence regarding the magnitude of redox potential response to the variation in the identity of surface-complex Fe(II) species and the quantitative measurements of the Fe(II)-to-Fe(III) electron transfer rate.…”

Heterogeneous oxidation of Fe(II) on iron oxides in aqueous systems: Identification and controls of Fe(III) product formation

“…O 2 ) and to the transformation of groundwater contaminants. Over the past 20 years, numerous reports have shown the combination of dissolved Fe(II) and Fe(III)-bearing minerals to be a potent reductant for many organic and inorganic contaminants including nitroaromatics (Klausen et al, 1995;Charlet et al, 1998;Elsner et al, 2004;Williams and Scherer, 2004;Hartenbach et al, 2006), explosives (Gregory et al, 2004;Nefso et al, 2005), chlorinated solvents (Buchholz et al, 2011), pesticides (Strathmann and Stone, 2003;Nano and Strathmann, 2008), metals (Charlet et al, 1998(Charlet et al, , 2002Buerge and Hug, 1999;Peretyazhko et al, 2008), and nitrite (Sorensen and Thorling, 1991;Charlet et al, 1998). Fe(III)-bearing oxides and hydroxides (such as goethite (a-FeOOH), hematite (aFe 2 O 3 ), and magnetite (Fe 3 O 4 ), hereafter collectively termed "Fe-oxides") provide reactive surface sites that can sorb Fe(II) atoms and aqueous oxidants and couple the transfer of electrons between them.…”

Redox behavior of magnetite in the environment

“…At neutral pHs, ferrous iron (Fe 2+ ) will readily sorb to several substrates commonly found in the environment, including clay minerals, metal oxides, and bacteria (21,23,(164)(165)(166)(167)(168)(169)(170)(171)(172)(173). Under anaerobic conditions, sorbed Fe 2+ forms a stable Fe 2+ surface complex for some substrates (e.g., Al and Ti oxides) (24,164,165), while for others, a more complex reaction occurs, which involves electron transfer between the Fe 2+ atom and the underlying solid phase (e.g., Fe 3+ oxides, clay minerals) (23,24,29,30,74).…”