(169g) Preparation of Magnetic Hollow Zsm-5/Ni Composite Spheres and Fibers

A simple template method was developed for the preparation of magnetic hollow ZSM-5/Ni composite spheres and fibers. This was fulfilled by first coating Ni layers on polystyrene (PS) microspheres, poly(vinylidene fluoride) (PVDF) hollow fibers microfiltration membranes, and cellulose acetate fibers from cigarette filters, respectively, by electroless plating, followed by growing ZSM-5 layers on the resulting Ni/template composites. Magnetic hollow ZSM-5/Ni spheres and fibers were subsequently prepared by calcination and reduction (if necessary) of the ZSM-5/Ni/ template composites. The samples were characterized by SEM, XRD, TG, EDX, temperature-programmed reduction (TPR) and a vibrating sample magnetometer (VSM). The results indicated that the hollow ZSM-5/Ni composites inherited magnetic property from the nickel layers. Their magnetization values could be adjusted by regulating the thickness of the nickel layer of the Ni/template composites, which was implemented by controlling the time of electroless plating. By controlling the hydrothermal treatment time and temperature, the thickness of the zeolite layers can be regulated. For the preparation of the hollow spheres, a continuous ZSM-5 layer with a thickness of 400 nm was formed on the surface of Ni/PS spheres after one cycle of hydrothermal treatment at 80 ^oC for 36 h. The saturation magnetization (Ms) and the coercivity (Hc) values of the hollow ZSM-5/Ni spheres with the Ni/PS spheres prepared by ultrasonic electroless plating for 4 min were about 14.08 emu/g and 88.95 Oe. When PVDF hollow fibers were used as the template, the resulting magnetic hollow ZSM-5 hollow fibers showed a round structure in cross-section with inner and outer diameters of ca. 600 and 800 mm, respectively; while the magnetic hollow ZSM-5 hollow fibers showed a trefoil structure in cross-section with an inner size of ca. 20 mm when the cellulose acetate fibers were used. The saturation magnetization value and the BET specific surface area of the magnetic hollow ZSM-5/Ni fibers were over 20 emu/g and 100 m²/g, respectively.

Keywords: hollow sphere, hollow fiber, magnetic, zeolite

Acknowledgement: This work is supported by Program for Changjiang Scholars and Innovative Research Team in University (PCSIRT 0732) and National Natural Science Foundation of China (No. 20676059)