Thermal dehydration kinetics of non-crystalline manganese borate

Abstract

In this study, non-crystalline manganese tetrahydric orthoborate (MnH₄(BO₃)₂) is synthesized by using MnSO₄.H₂O, NaOH and H₃BO₃ via hydrothermal method. The characterizations of the synthesized compounds are conducted using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Thermal dehydration studies are conducted using the thermogravimetric analysis (DTG/TG). From the XRD result, amorphous manganese borate is synthesized and the FTIR spectrum shows characteristic borate vibrations in the IR region. A uniform particle size distribution at the micron scale with partially agglomerated is observed from SEM images. The thermogravimetric results dehydration process occurs between the temperatures of 40 – 270°C in one-step reaction with average weight loss of 19.26%. Average activation energies ware determined by using the non-isothermal kinetics methods of Coats-Redfern, Horowitz-Metzger and Van-Krevelen and found as 37.83, 46.54 and 37.88 kJ/mol, respectively.