Thermal dehydration kinetics and characterization of pandermite

DUMANLI F. T.

Main Group Chemistry, cilt.16, sa.2, ss.151-161, 2017 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 16 Sayı: 2
  • Basım Tarihi: 2017
  • Doi Numarası: 10.3233/mgc-170233
  • Dergi Adı: Main Group Chemistry
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.151-161
  • Anahtar Kelimeler: characterization, KAS method, Kissenger method, non-isothermal kinetic, OFW method, Pandermite, thermal decomposition
  • Yıldız Teknik Üniversitesi Adresli: Evet

Özet

Pandermite (Ca4B10O19 7H2O) can be defined as a type of calcium borate hydrate which generally founds in Turkey and USA. It has been identified by using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and Scanning electron microscope (SEM) during dehydration process. Thermal gravimetry and differential thermal gravimetry (TG/DTG) methods have been applied to investigate the thermal dehydration kinetic of pandermite. The results showed that it lost its crystal water via three-step process approximately between 280°C and 550°C temperatures. Activation energies (Ea) were found as 98.83, 136.86 and 391.24kJ using Ozawa-Flynn-Wall (OFW) model; 89.82, 133.16 and 399.01kJ using Kissinger-Akahira-Sunose (KAS) model; and 140.78, 131.01 and 486.22kJ using Kissinger non-isothermal kinetic model for steps 1, 2 and 3, respectively. At the end of the dehydration process, Pandermite lost its water content and it decomposed to CaB2O4 (powder diffraction file number: 00-009-0247) and B2O3 (powder diffraction file number: 01-072-0626) occurred.