Stereolithography as a manufacturing method for a hierarchically porous ZSM-5 zeolite structure with adsorption capabilities

Abstract

Hierarchically porous structures are important in adsorption applications and can be used in gas treatment. Hierarchy in adsorbents offers flow channels on different scales, resulting in fast gas flow into a structure. Additive manufacturing, a technology capable of forming intricate geometries, was seen as a potential method to form porous adsorption structures. Stereolithography was chosen as the fabrication method for hierarchically porous zeolite structures because of its high resolution and superior forming capability. The focus of this study was on tailoring the properties of light-cured resin to maximize stability during shaping and shape retention in the debinding stage. Successful slurry preparation was required for demonstrating that monoliths with channel geometry and retained adsorption properties can be manufactured with stereolithography. The final printed structures exhibited hierarchical porosity consisting of flow channels, macropores between the primary particles and the characteristic microporosity of zeolite framework. The structure was manufactured by using blue light to cure layers of resin containing ZSM-5 zeolite. An appropriate debinding heat-treatment cycle was generated based on the TGA and DSC thermal analysis results. The properties of the porous structure were analysed by comparing the BET surface area, XRD patterns and SEM images of as-received powder and a debound piece. The measured BET adsorption properties of the final monoliths remained comparable to the as-received ZSM-5 powder. Based on this study, stereolithography can be utilized to manufacture porous zeolite structures.