Innovative Analytical Methodology Combining Micro-X-Ray Diffraction, Scanning Electron Microscopy-Based Mineral Maps, and Diffuse Reflectance Infrared Fourier Transform Spectroscopy to Characterize Archeological Artifacts

Abstract

Excavations at the 14th century Moorish rampart (Granada, Spain) unearthed a brick oven alongside black ash and bone stratigraphic layers. In situ evidence suggests the oven served to fabricate a wall coating including powdered burnt bones. Original ad hoc analyses improved on conventional methods were used to confirm this hypothesis. These methods enable (i) nondestructive micro-X-ray diffraction (mu-XRD) for fast mineralogical data acquisition (approximately 10 s) and moderately high spatial (approximately 500 microm) resolution and (ii) identification and imaging of crystalline components in sample cross-sections via mineral maps, yielding outstanding visualization of grain distribution and morphology in composite samples based on scanning electron microscopy-energy dispersion X-ray spectrometry (SEM-EDX) elemental maps. Benefits are shown for applying diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) vs transmittance-FT-IR (T-FT-IR) to analyze organic and inorganic components in single samples. Complementary techniques to fully characterize artifacts were gas chromatography/mass spectroscopy (GC/MS), optical microscopy (OM), conventional powder XRD, and (14)C dating. Bone-hydroxyapatite was detected in the coating. Mineralogical transformations in the bricks indicate oven temperatures well above 1000 degrees C, supporting the hypothesis.

Neutralization of red mud using CO2 sequestration cycle

“…The leaching of sodium ions in the cycles 1, 2, and 3 were ∼32.75, ∼29.87, and ∼26.51% (w/w) whereas the compound Na 2 O (Na 2 CO 3 , NaHCO 3 and H 2 CO 3 ) was ∼40.82, ∼43.52, and ∼33.31, respectively. [22]. This may be due to chemisorbed CO 2 in fresh RM and NRM respectively.…”

A Study on the Characterization of Red Mud

“…Here the change in the dipole moment of the water hydroxyl-stretching plays an important role and so the intensity of the infrared spectrum is more. Stretching vibrations of C=O is found at 1449.40 cm -1 confirms the presence of carbonate groups [14]. …”

Utilization of activated CO2-neutralized red mud for removal of arsenate from aqueous solutions

“…It revealed that the peaks of gibbsite in NRM were increased prominently and a new mineral ilmenite (FeTiO 3 ) was formed, due to CO 2 treatment. But, after thermal treatment of [23][24][25]. This may be due to chemisorbed CO 2 in RM and NRM, respectively.…”