Thermal dehydration kinetics and characterization of pandermite

Article type: Research Article

Authors: Senberber, Fatma Tugce^{; *}

Affiliations: Programme of Occupational Health and Safety, Atasehir Adiguzel Vocational School, Turkey

Correspondence: [*] Corresponding author. Fatma Tugce Senberber, Programme of Occupational Health and Safety, Atasehir Adiguzel Vocational School, Turkey. Tel.: +90 216 4557770; Fax: +90 216 5482817; E-mails: [email protected]; [email protected].

Abstract: 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 391.24 kJ using Ozawa–Flynn–Wall (OFW) model; 89.82, 133.16 and 399.01 kJ using Kissinger–Akahira–Sunose (KAS) model; and 140.78, 131.01 and 486.22 kJ 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.

Keywords: Pandermite, non-isothermal kinetic, thermal decomposition, characterization, KAS method, OFW method, Kissenger method

DOI: 10.3233/MGC-170233

Journal: Main Group Chemistry, vol. 16, no. 2, pp. 151-161, 2017