Synthesis of Size Distribution Controllable Zeolite Nanocrystals via a Novel Confined Space Strategy

A novel confined-space synthesis method has been developed to synthesize zeolite nanocrystals. Colloidal silica nanoparticles serving as the silica source as well as the hard template were embedded in the mesoporous carbon via in situ polymerization of furfuryl alcohol (FA) in the presence of tri-block copolymer (Pluronic P123), and then reacted with an alkaline aqueous solution (Na2O-Al2O3-H2O) infiltrated through the mesoporous channels of the carbon matrix. The synthetic zeolite nanocrystals possess similar size distribution corresponding to that of colloidal silica nanoparticles. The synthesis of zeolite NaA nanocrystals is demonstrated. The amount of FA, aging time and hydrothermal time showed significant effects on the morphology and crystal size of zeolite NaA. N2 sorption, X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) were used to characterize the mesoporous carbon-silica composite and zeolite NaA nanocrystals. Dynamic Light Scattering (DSL) was used to measure the particle size and size distribution of zeolite nanocrystals as well as colloidal silica nanoparticles. Zeolite nanocrystals synthesized in this study are useful to fabricate zeolite-polymer nanocomposite membranes and the as-synthesized carbon-zeolite nanocomposite has high potential to serve as hierarchical nano-structured zeolite adsorbent for wastewater treatment.