Hollow ZSM-5 Zeolite Microspheres with Improved Adsorption and Catalytic Properties

A new kind of uniform hollow zeolite spheres were successfully synthesized by non-hard template synthetic method, which involves two key steps: firstly, the conventional hydrothermal synthesis process of zeolite spheres by using polyethylene glycol (PEG) as soft template, and then, the rapid post-alkaline-etching (PAE) technique. Structural features were characterized by XRD, N-2 isotherm, SEM, and TEM. The performance in the organic waste-water treatment and catalytic cracking of bulky molecules were also measured. It was found that crystallinity of the product underwent a reducing tendency after alkaline etching treatment, but the mesoporosity and pore volume were promoted. The diameter and shell thickness of hollow zeolite spheres were about 600 nm and 100 nm, resPectively. Moreover, such hollow structure demonstrates remarkably a threefold capability increase in adsorption of benzene molecules in methanol solution if compared with conventional zeolite spheres. Such capability can be basically kept after repeating 6 times, indicating high capability and stability in adsorption. Enhanced catalytic activities were also approved in cracking of isopropyl benzene and triisopropyl benzene.