A combined synchrotron powder diffraction and vibrational study of the thermal treatment of palygorskite–indigo to produce Maya blue

摘要: The heating process (30–200 °C) of a palygorskite-indigo mixture has been monitored in situ and simultaneously by synchrotron powder diffraction Raman spectroscopy. During this process, the dye clay interact to form Maya blue (MB), pigment highly resistant degradation. It is shown that formation very stable occurs 70–130 °C interval; i.e., when palygorskite starts loose zeolitic water, accompanied reduction crystallographic parameter, as well alterations C=C C=O bonds indigo. Mid- near-infrared spectroscopic work microporosity measurements, employed study rehydration after complex formation, provide evidence for inhibition MB compared with palygorskite. These results are consistent blocking tunnel entrance indigo molecules possible partial penetration inside tunnels. surface silanols not perturbed indigo, suggesting complex.