Preparation of NaCl-incorporated plugged mesoporous silica using a cost-effective precursor and applications to the hydrodechlorination of chlorinated hydrocarbons

The preparation of SBA-15 type plugged mesoporous silica using an inexpensive silica source in a two-step process is described. The resulting material was used as a catalyst support for a hydrodechlorination (HDC) reaction. The structure and morphology of the mesoporous silica and catalysts were determined using trasmission electron microscopy (TEM), small angle X-ray scattering (SAXS) and scanning electron microscopy (SEM). The contents and particle size of the metal incorporated into the catalysts were measured by ICP atomic emission spectrometry (ICP-AES) and X-ray diffraction analysis (XRD). The material (hereafter referred to as 2MS) included about 2% Na in the form of NaCl. The pore structures of SBA-15 and 2MS were similar but 2MS showed an atypical plugged shape of the N₂ desorption isotherm. Furthermore, the pore wall thickness was quite high (5 nm), and particles were large and in close proximity to each other in the 2MS. The micropore area ratio measured using a t-plot method was large, over 25%. When a 2MS-supported palladium catalyst was used for hydrodechlorination of 1,1,2-trichloroethane, the catalyst had a stronger resistance to deactivation.