Kinetics of chromium(III) oxidation to chromium(VI) by reaction with manganese dioxide

Kinetics of oxidation of Cr(III)-organic complexes by H2O2

“…Manganese (hydr)oxides have been identified as the major oxidant of Cr(III) in the environment (Bartlett and James, 1979;Eary and Rai, 1987;Fendorf et al, 1992;Fendorf and Zasoski, 1992;Johnson and Zyla, 1991;Manceau and Charlet, 1992;Tzou et al, 2002). Oxidation of Cr(III) by dissolved oxygen is thermodynamically feasible under alkaline conditions, although this process is kinetically limited (Bartlett, 1979;Nakayama et al, 1981).…”

Groundwater quality in the Western San Joaquin Valley study unit, 2010: California GAMA Priority Basin Project

“…Chromium(III), the dominant form in most minerals, is only sparingly soluble in water and strongly sorbed in mineral surfaces (Nriagu and Nieboer, 1988;Kotas and Stasicka, 2000). In the presence of manganese oxides, chromium(III) is oxidized to chromium(VI) , which under oxic, alkaline conditions, can desorb from mineral surfaces and become soluble in groundwater as an oxyanion (Eary and Rai, 1987;Kotas and Stasicka, 2000;Izbicki and others, 2008). The concentration of chromium(VI) in groundwater from natural sources generally is greatest where the combination of all the following conditions exist: abundant, easily weathered chromium-bearing minerals; manganese oxides on surfaces of aquifer materials; oxic, alkaline groundwater; and long residence times others, 2008, 2015;Morrison and others, 2009;Mills and others, 2011).…”

Reduction of Contaminant Mobility at the TNX Outfall Delta Through the Use of Apatite and Zero-Valent Iron as Soil Amendments

“…If other metals are present, they may coprecipitate with the Fe(II/III)-oxyhydroxide. Chrome removal by Fe(0) is believed to be primarily through this reaction, whereby Cr/Fe(OH) 3 solid solutions are formed (Eary andRai 1987, Sass and. …”