Synthesis of layered double hydroxides from eggshells

Ca–Al and Ca–Fe layered double hydroxides (LDHs) were successfully synthesized from chicken eggshells by an ultrasonic wave assistant method. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) techniques. XRD and TEM analyses showed that the 4Ca–Al LDHs were of high purity but other samples were not. The present study provides a simple, efficient and environmental friendly method to obtain LDHs from biowaste eggshells, in which additional alkaline solution is not required for synthesis. Moreover, eggshells provide all the requisite bivalent metal ions, which are needed to form layered double hydroxides.

This is the XRD pattern and TEM image of 4Ca–Al layered double hydroxide, which is obtained from eggshells. It can be seen that the sample is of layered double hydroxide and shows the plate-like agglomerations with an average size of 20–100 nm.Figure optionsDownload as PowerPoint slideHighlights
► We synthesize layered double hydroxides from eggshells.
► Eggshells are the mainly material in this method.
► The additional alkaline solution is not required.