Thierry Allard

TL;DR: In this paper, the authors deal with the direct determination of colloidal forms of iron in river-borne solids from main rivers of the Amazon Basin using ultrafiltration associated with various techniques including electron paramagnetic resonance spectroscopy (EPR), high resolution transmission electron microscopy (HRTEM), and micro proton-induced X ray emission analysis (μPIXE).

TL;DR: In this paper, the substitution of Fe3+ in the kaolinite structure is studied by EPR spectrometry and by FTIR spectrometers on a large set of kaolins from different origins.

TL;DR: In this paper, the second and fourth-order fine-structure parameters of Fe (super 3+) ions in disordered local environments, including multimodal site-to-site distributions, were determined using electron paramagnetic resonance spectroscopy at both the X and Q-band frequencies.

TL;DR: In this paper, the structure of natural uranium-bearing, recently formed products arising from oxidative weathering of a U deposit (Peny, Massif Central, France) was studied to determine mechanisms of U-trapping by natural gels.

TL;DR: In this paper, the authors investigated the OH-stretching modes of kaolinite group minerals, namely, dickite, and nacrite, within the density functional theory framework and obtained good agreement between theoretical and experimentally derived structures.