The effects of solvent and microwave on the preparation of Magnesium Oxide Precursor

Abstract

Four methods including hydrothermal method, glycolhydrothermal method, microwave-hydrothermal method and glycol-microwave-hydrothermal method were used to prepare magnesium oxide precursor by the reaction of MgSO 4 ·7H 2 O with (NH 4 ) 2 CO 3 . The composition, crystallinity, morphology, aspect ratio, yield, functional groups, atom distribution, and interplanar spacing of the sample were investigated by X-ray diffraction (XRD), Scan Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and High Resolution Transmission Electron Microscope (HRTEM). The properties of Magnesium Oxide precursor were compared with each other. The results of FT-IR and XRD showed that the crystals were all nesquehonite. However, it was shown by FT-IR results that the crystals prepared by glycol-microwave-hydrothermal method contained OH − and HCO 3 − groups, which indicated that the Mg(OH)(HCO 3 )·2H 2 O type crystals would be facilitated by this method. The glycol-hydrothermal method can create high quality Magnesium Oxide precursor with a high degree of crystallinity, high purity, high aspect ratio, smooth surface, and good dispersibility.

Influence of alkali metal ions (K+ and Na+) on the preparation of magnesium hydroxide hexagonal flakes

“…The hydrothermal method is commonly employed to control nucleation growth of the Mg(OH) 2 crystal surface by regulating its dissolution and recrystallization. 18 Currently, the use of ultrasound, microwave-assisted technology, 19 and additives, 20 among other, to regulate Mg(OH) 2 formation during hydrothermal reactions is a hot topic. Further, the most commonly employed method involves regulating the nucleation, crystallization, and other growth processes of Mg(OH) 2 using various additives.…”