New synthetic route to Mg–Al–CO3 layered double hydroxide using magnesite

A novel synthesis of Mg–Al–CO3 layered double hydroxide (LDH) through chemical precipitation and hydrothermal methods has been investigated in this paper. The advantages of this method are using magnesite as magnesium source and no CO2 released in the process of preparation. Mg–Al–CO3 LDH (ZY) prepared under the optimized condition (the molar ratio of magnesite and Al(NO3)3·9H2O was 2.5:1; the aging time and temperature were 16 h and 100 °C, respectively) was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric and differential thermal analyser (TG–DTA) and scanning electron microscope (SEM). The crystal morphology of the prepared LDH displays platelet-like structure with a hexagonal shape, which is agreed with the LDH produced by industrial chemicals. Through elemental analysis and inductively coupled plasma-atomic emission spectrometry (ICP-AES), the chemical formula of ZY is determined as Mg0.70Al0.30(OH)2(CO3)0.15·0.6H2O.

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► The use of magnesite to prepare Mg–Al–CO3 LDH is novel.
► The result sample is systematically studied.
► Furthermore, the cost of preparing Mg–Al–CO3 LDH may be reduced through this synthetic route.
► In the synthesis process, there is no CO2 released. That is significant to environmental protection.