ISSN 0862-5468 (Print), ISSN 1804-5847 (online) 

Ceramics-Silikáty 57, (3) 243 - 250 (2013)


MINERALOGY OF HALLOYSITES AND THEIR INTERACTION WITH PORPHYRINE
 
Vašutová Vlasta 1, Bezdička Petr 2, Lang Kamil 2, Hradil David 2
 
1 Charles University in Prague, Faculty of Science, Albertov 6, 128 43 Prague, Czech Republic
2 Institute of Inorganic Chemistry of the AS CR, v.v.i., Husinec-Řež 1001, 250 68 Řež, Czech Republic

Keywords: Organoclays, Mineralogy, Halloysite, Porphyrine, CEC
 

Samples representing two modifications of halloysites, dehydrated (7 Å) and hydrated (10 Å) forms, respectively, were examined with the aim to select suitable candidates for to be used as carriers of porphyrine photoactive molecules. The samples were analysed by powder X-ray diffraction (pXRD), infrared spectroscopy (FT-IR), and high resolution transmission electron microscopy (HRTEM). Chemical composition was also determined. For the determination of cationic exchange capacity (CEC) the silver thiourea method (AgTU) was used. Silver cations concentrations in the solution before and after the interaction were determined by atomic absorption spectrometry (AAS). By the interaction of two pure hydrated halloysites with porphyrine it was found that porphyrine does not intercalate the interlayer space, but it is adsorbed on the outer surface of halloysite. This interaction changed the colour of clay sample from white to green. The changes were also clearly visible on diffuse reflectance spectra (DRS).


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