Geochemical modeling for the formation and dissolution of ferrihydrite colloids

Abstract

Geochemical reaction model for ferrihydrite in the Lake Karachai area has been developed. The model consists of four processes: the diffusion of Fe(II) from rocks, the oxidation of Fe(II) to Fe(III) by NO3-, the formation and dissolution of ferrihydrite colloids, and the formation of goethite and hematite. The numerical calculation shows that the colloids exist in groundwater for more than 10 000 years in the Lake Karachai area.