Phyllosilicate-content influence on the spectroscopic properties and antioxidant capacity of Iberian Cretaceous clays

Kaolinite-rich Cretaceous clay sediment samples from Burgos (Spain) have been analyzed by elemental analysis, X-ray fluorescence, inductively coupled plasma mass spectrometry, X-ray diffraction and different spectroscopic techniques, as Fourier Transform Infrared, ultraviolet-visible and electron paramagnetic resonance. The clay sediment samples mainly contain quartz, muscovite and kaolinite. Different radicals, as A- and B-Centers in kaolinite and organic paramagnetic species, are detected. An illite/kaolinite FTIR band ratio parameter (1KB) is proposed to infer the illite/kaolinite proportion, which can be useful to graphically visualize the iron-substituted Al(III) sites. Studies of the activity as scavengers of DPPH and ABTS radicals show that samples with a larger amount of orthorhombic Fe(III) ions replacing Al(III) ions exhibit a higher antioxidant capacity. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Kaolinite-rich Cretaceous clay sediment samples from Burgos, Spain were analyzed using various techniques, revealing the presence of quartz, muscovite, and kaolinite, as well as different radicals. A proposed illite/kaolinite FTIR band ratio parameter (1KB) can help infer the illite/kaolinite proportion and visualize iron-substituted Al(III) sites. Studies on the activity as scavengers of DPPH and ABTS radicals showed that samples with more orthorhombic Fe(III) ions replacing Al(III) ions exhibited a higher antioxidant capacity.