Industrial & Engineering Chemistry Research, Vol.47, No.15, 5746-5750, 2008
Preparation of layered double hydroxide microspheres by spray drying
In order to fully exploit their attractive properties in actual practical applications, layered double hydroxide (LDH) materials should be fabricated into macroscopic form. A magnesium-aluminum layered double hydroxide (MgAl-LDH) containing interlayer carbonate anions has been obtained using a synthesis route involving separate nucleation and aging steps, and microspheres of the material formed in a subsequent spray drying process. The resulting products are composed of nanosized LDH particles aggregated into solid microspheres with a diameter of 10-50 mu m, a sphericity of 0.84, modal pore access diameter of 87.9 nm, surface area of 43 m(2)/g, and total pore volume of 1.29 cm(3)/g. The presence of an accessible diffusion pathway in the macropore domain of the LDH microspheres offers the possibility of enhanced performances in a wide range of applications. Furthermore, the spherical morphology of the materials was retained when the LDHs were converted into solid base catalysts by calcination and subsequent rehydration, indicating the robust nature of the macroscopic particles.