Impact of ferrihydrite transformation on incorporated zinc in field conditions

Ferrihydrite (noted Fh), a poorly crystalline iron oxyhydroxide, is a naturally-abundant efficient scavenger of trace metals. Here, we investigate the fate of zinc (Zn) incorporated in the Fh structure during the Fe(II)-induced transformation of Fh in the field and in laboratory incubations. We will determine the Zn speciation in transformation products of Fh-Zn by bulk and micro-focused Extended X-Ray Absorption Fine Structure (EXAFS) at the Zn K-edge, in order to evaluate the impact of mineral transformation on the mobility of this trace metal, in conditions approaching the complexity of natural surface environments.