Effect of titanium source on structural properties and acidity of Ti-pillared bentonite


TURGUT BAŞOĞLU F.

CHEMICAL PAPERS, cilt.70, sa.7, ss.933-945, 2016 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 70 Konu: 7
  • Basım Tarihi: 2016
  • Doi Numarası: 10.1515/chempap-2016-0026
  • Dergi Adı: CHEMICAL PAPERS
  • Sayfa Sayıları: ss.933-945

Özet

Ti-pillared bentonites (Ti-PBs) were synthesised using bentonite from the Hancili region in Turkey. Ti(IV) chloride, Ti(IV) ethoxide and Ti(IV) propoxide were used as the titanium sources; the syntheses were carried out using different H+/Ti ratios, bentonite suspension percentages and calcination temperatures. Titanium was found in the form of titanium dioxide for all the sources. The Ti(IV) chloride source afforded a sample with a significantly higher specific BET surface area (by 323 m(2) g(-1)), TiO2 content of 50.5 mass % and a more microporous structure with a micropore volume of 0.112 cm(3) g(-1); the Ti(IV) propoxide source afforded a more mesoporous structure with a higher total pore volume. The micropore region showed the formation of pores of different sizes, while prominent narrow peaks were obtained in the mesopore region. Ti-PBs, which exhibited only the anatase phase of titanium dioxide, yielded high Bronsted and Lewis acidities. When the rutile phase and the anatase phase occurred together, as a result of the lower TiO2 content, the Bronsted and Lewis acidities of the Ti-PBs decreased. The use of Ti(IV) chloride and Ti(IV) propoxide sources at H+/Ti ratios of 4.0 and a bentonite suspension percentage of 2.0 resulted in samples exhibiting strong Bronsted acidity. (C) 2016 Institute of Chemistry, Slovak Academy of Sciences