Abstract ................................................................................................. 262 13.1 Introduction ................................................................................ 262 13.2 Experimental .............................................................................. 266 13.3 Results and Discussion............................................................... 267 13.4 Conclusions ................................................................................ 275 Acknowledgments ................................................................................. 275 Keywords .............................................................................................. 275 References ............................................................................................. 276

2 O

3 ∙3H

2 O AND

3 ∙H

2 O) BY THERMAL

MEHMET GÖNEN1,*, DEVRIM BALKÖSE2, and SEMRA ÜLKÜ2

1Department of Chemical Engineering, Engineering Faculty, Süleyman Demirel University, Batı Yerleşkesi, 32260 Isparta, Turkey 2Department of Chemical Engineering, Izmir Institute of Technology, Gülbahçe Köyü-Urla, 35430 Izmir, Turkey *Corresponding author. E-mail: [email protected]

ABSTRACT

The kinetic parameters for the dehydration of zinc borates, 2ZnO∙3B2O3∙3H2O (ZnB-1) and 4ZnO∙B2O3∙H2O (ZnB-2), were determined using dynamic thermal gravimetric (TG) technique. Kissinger method was used in the analysis of the TG and derivative TG data for determination of dehydration kinetics. Zinc borate (ZnB-1) has started to loose mass at 290°C and its thermal dehydration consists of mainly two consecutive kinetic steps related to the OH group interactions as inferred from derivative TG curves. The dehydration activation energies of ZnB-1 were calculated as 183.5 and 556.1 kJ mol−1 for the first and second kinetic steps, respectively. On the other hand, ZnB-2 began to dehydrate at 450°C and dehydration took place only in one step and the dehydration activation energy was calculated as 201.7 kJ mol−1.