“…Different techniques have been previously tested for the identification of Cr(VI) complexes on Fe or Al oxyhydroxide surfaces [22][23][24][25]. In addition, the redox transformation of Cr(VI) during adsorption onto environmentally relevant surfaces, including oxides and clay minerals have been investigated using X-ray photoelectron spectroscopy (XPS), Fourier transformed infrared spectroscopy (FTIR), and X-ray absorption spectroscopy (XAS) [22,[26][27][28]. Therefore, studies using coupled modeling and spectroscopic approaches to soil mineral surfaces would provide valuable information.…”