Ultrasonic-Assisted Synthesis of Zinc Borates: Effect of Boron Sources

Abstract

Sonochemistry meaning ultrasound-assisted chemistry plays an important role in the synthesis of inorganic compounds. Among these inorganic compounds, zinc borates are used for the flame-retarding agent. In this study using zinc chloride (ZnCl2), boric acid (H3BO3), Na2B4O7and#183;10H2O, Na2B4O7and#183;5H2O and NaOH as raw materials, a zinc borate compound in the formulae of Zn3B6O12and#183;3.5H2O was obtained using an ultrasonic probe. Crystal structures of samples were identified using X-ray diffraction (XRD). The symmetric and asymmetric stretching between boron and oxygen atoms were searched by Fourier-transform infrared (FT-IR) and Raman spectroscopies. The effects of boron sources on sample morphology were examined by scanning electron microscopy (SEM). From the results, it was seen that Zn3B6O12and#183;3.5H2O can easily be produced from these raw materials with the synthesis parameters of 80-90and#176;C and 40-55 min. From the SEM results, it was seen that the minimum particle size obtained was 172 nm. Reaction efficiencies were calculated between 79.6 and 94.0 and#177; 0.5%. Thermal feature of the obtained pure phase, investigated with the thermogravimetric analyses. The dehydration of the synthesized Zn3B6O12and#183;3.5H2O was seen between 262 and 413and#176;C with a total mass loss of 13.25%.