Fabrication and application of silicalite-1 and TS-1 hollow fibers with polyethylene imine (PEI) fibers as substrates

Silicalite-1 and titanium containing silicalite-1 (TS-1) hollow fibers were fabricated with polyethylene imine (PEI) fibers as substrates. The acid treated PEI fibers were positively charged and can be effectively coated with silicalite-1 or TS-1 nanocrystals from their colloidal solution. The adsorbed silicalite-1 or TS-1 nanocrystals grew up and became more compact upon two days of vapor phase Ostwald ripening in autoclave. Silicalite-1 and TS-1 hollow fibers were obtained after calcination at 400 °C in air. The shell thickness of the hollow fibers is ∼1 μm. Hydroxylation of phenol with H2O2 was investigated over TS-1 based catalysts in order to compare influences of nanocrystals composed macrostructure and Al2O3 binder on the catalytic activities.