Physicochemical and Textural Characterization of Perchlorated and Persulphated Titania

Abstract

Samples of perchlorated and persulphated rutile were obtained by soaking the solid in aqueous solutions of HClO 4 and (NH 4 ) 2 S 2 O 8 of 0.05 M, 0.10 M and 0.20 M concentration and characterized by XRD and FT-IR spectroscopic studies and by acidity and textural assessment. The XRD results indicated that the interaction of titania with the loaded anions, i.e. ClO -4 and S 2 O 8 2-, resulted in an increase in the volume of the unit cell mainly due to an increase in the c 0 value of the tetragonal crystal lattice. The IR spectra showed that both ClO -4 and S 2 O 8 2-anions were linked to the surface via bidentate bridging. Such behaviour created strong acidic sites as probed by pyridine (pK a = 5.3) whose number increased with increasing anion loading. The acidity of the perchlorated samples was higher than that of the persulphated materials. Textural analysis showed that the specific surface areas of both samples responded to the loading process to a lower extent than the total pore volume and correspondingly to the average hydraulic radius, since the latter changed in relation to the total pore volume.

Dual functioning TiO₂-brilliant yellow composite for efficient removal of methylene blue from water

“…The broad band appearing at 667 cm −1 in Ti-BY spectrum may prove the formation of S-O-Ti bonds. Also the strong peak appearing around 1643 cm −1 in BY spectrum has shifted to the 1635 cm −1 in Ti-BY as a weak peak indicating the presence of N=N bond, but, shifted to a lower value due to the formation of S-O-Ti bond (Moussa, 2000).…”

Solid Acids from Persulphated and Perchlorated Physical Mixtures of Zirconium and Titanium Hydroxides

“…Anions such as WO 4 2-, CO 3 2-, Cl -, For OHare also reported as generating surface acidity when incorporated in metal oxides (Hino et al 1979;Wu and Yu 1990). In contrast, the use of perchlorate or persulphate anions in this context has hardly been commented upon in the literature (Mishra and Parida 1999;Moussa 2000). The binary TiO 2 -ZrO 2 oxides also feature among a large number of solid acids.…”