Large scale synthesis of porous microspheres of Mg-Al-layerd double hydroxide with improved fire suppression effectiveness

Porous microspheres of Mg-Al layered double hydroxide (LDH) were fabricated in large scale through a simple sonication-assisted method in the mixed solvent of ethylene glycol and water. Contrast experiments showed that sonication and ethylene glycol both played important roles for the formation of the porous nanostructures of Mg-Al-LDHs. A series of techniques of XRD (X-ray Diffraction), FTIR (Fourier Transmission Infrared Spectroscopy), SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), BET (Brunauer-Emmett-Teller surface analysis) and TG-DTA (Thermalgravimetric-Differential Thermal Analysis) were used to characterize the product. Laboratory-scale fire extinguishment tests showed that thus-prepared porous LDHs showed much superior performance to that of the solid particulate counterpart for relatively shorter extinguishing time and smaller amount of agents required. Such an improvement could be reasonably ascribed to the special porous structure and nanosize of as-prepared Mg-Al-LDHs microspheres.