Spherical silica agglomerates possessing hierarchical porosity prepared by spray drying of MCM-41 and MCM-48 nanospheres

Hierarchically ordered porous materials possessing both meso- and macropores can be obtained by agglomeration of spherical primary particles of mesoporous MCM-41 and MCM-48 materials using the spray drying technique. A highly interconnected bimodal pore network is obtained due to the intra- and inter-particle pore systems within the micronsized spherical agglomerates. Further packing of the agglomerates will result in a three-modal hierarchical pore system, where the first level of porosity originates from the ordered mesopores inside the primary particles, the second level is a result of the particle internal porosity, and the third level is due to the voids between the agglomerates. The materials were characterized by nitrogen physisorption, mercury porosimetry, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). (C) 2003 Elsevier Inc. All rights reserved.