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Abstract: Zeolitic imidazolate framework-8 (ZIF-8)/chitosan composites were prepared in the chitosan hydrogels. The concentrations of the chitosan and the alkaline solution were varied to the synthesis of the ZIF-8/chitosan composites. In the chitosan hydrogels with the addition of ammonium hydroxide solution, the resulting ZIF-8 crystals exhibited an unusual XRD structure that the XRD peak at about 18o (222) became the strongest. The XRD peak intensity ratio of (222)/(011) increased from 0.68 to 1.5–5.2 in the presence of chitosan hydrogels. ZIF-8/chitosan composites (FC2) were composed of aggregated nanosized particles, and exhibited a higher CO2 adsorption than normal ZIF-8 crystals. After removing chitosan from FC2, XRD pattern of the resulting ZIF-8 crystals returned to the normal state and the morphology kept the same as the composite. [Copyright &y& Elsevier]

Abstract: Magnetic ZSM-5/Ni/fly-ash hollow microspheres are prepared by using fly-ash cenospheres as the template. The preparation procedure mainly includes two steps, i.e., preparation of magnetic nickel/fly-ash composites by electroless plating and growth of the ZSM-5 layers on the nickel/fly-ash composites by a secondary growth method. The samples are characterized by scanning electron microscope, X-ray diffraction, nitrogen adsorption and vibrating sample magnetometer. The resulting ZSM-5/Ni/fly-ash hollow microspheres show integral hollow structure and magnetic property. They are floatable on water surface when the electroless plating time is 10 min and the hydrothermal synthesis time is 12 h at 180 °C. The floatability of these hollow microspheres can further be adjusted by changing the electroless plating and hydrothermal synthesis times. Furthermore, their magnetic property can also be managed by controlling the synthesis conditions. [Copyright &y& Elsevier]