PhD Candidate, Missouri University of Science and Technology
This study aims at developing novel structured zeolite monoliths with various compositions by using three dimensional (3D) printing techniques to promote the production of light olefins and catalyst stability in selective transformation of light alcohols. 3D-printed ZSM-5 and silicalite-1 monoliths were coated with a thin layer of SAPO-34 zeolite. Characterization results indicated that the 3D-printed monoliths were highly porous and their micropore surface area and pore volume further increased by consequent coating with SAPO-34 zeolite. The catalytic results showed that the thin layer of SAPO-34 on 3D-printed MFI structures impeded the gaseous mas transport but favored the production of light olefins. The total acidity of SAPO-34/3D-printed ZSM-5 structure was higher than both SAPO-34/3D-printed silica and uncoated 3D-printed ZSM-5 monolith which favored the light olefins production. Coating 3D-printed HZSM-5 monolith with SAPO-34 enhanced the ability to produce olefins while circumvented the quick coke formation. These results demonstrated that selectivity and reaction rate in dehydration of light alcohols to light olefins can be modulated by changes in catalyst topology and morphology.
Abstract: In this study, aqueous colloidal ZnO inks with tailored rheological properties have been developed for 3D printing of periodic structures. These periodic structures consisting of alternating layers with tetragonal symmetries were fabricated by extrusion of ZnO inks with concentration of 48 vol%. The as-prepared structures had well-defined and interconnected layers with rod diameters of 200 μm. The inks exhibited pseudoplastic behaviour and were in accordance with the power-law model. Oscillatory and creep-recovery measurements indicated that the inks had the appropriate viscoelastic behaviour and excellent printing characteristics. In order to acquire a high mechanical strength, the structures were sintered at various temperatures between 900 and 1500 °C, and their compressive strength was evaluated. The results indicated that 1500 °C was an optimum sintering temperature to obtain structures with high compressive strength up to 11.09 MPa. The reported ZnO inks offer multiple possibilities for the fabrication of novel structures for practical applications.
Pub.: 28 May '16, Pinned: 29 Jun '17
Abstract: Amine-based materials have represented themselves as a promising class of CO2 adsorbents, however their large-scale implementation requires their formulation into suitable structures. In this study, we report formulation of aminosilica adsorbents into monolithic structures through 3D printing technique. In particular, 3D-printed monoliths were fabricated using pre-synthesized silica-supported tetraethylenepentamine (TEPA) and poly(ethylenimine) (PEI) adsorbents using three different approaches. In addition, a 3D-printed bare silica monolith was prepared and post-functionalized with 3-aminopropyltrimethoxysilane (APS). Characterization of the obtained monoliths indicated that aminosilica materials retained their characteristics after being extruded into 3D-printed configurations. Adsorptive performance of amine-based structured adsorbents was also investigated in CO2 capture. Our results indicated that aminosilica materials retain their structural, physical and chemical properties in the monoliths. In addition, the aminisilica monoliths exhibit adsorptive characteristics comparable to their corresponding powders. This work highlights the importance of adsorbents materials formulations into practical contactors such as monoliths, as the scalabale technology platform, that could facilitate rapid deployment of adsorption-based CO2 capture processes on commercial scales.
Pub.: 12 Feb '17, Pinned: 29 Jun '17
Abstract: Propylene is an important constituent of many products that we rely upon in our daily life. This essential raw material is currently produced from fossil-derived feedstocks such as oil and natural gas. However, conversion of bioethanol to propylene represents an interesting opportunity for the utilization of renewable feedstocks such as bioethanol as one of the main biomass-derived products via dehydration process. The catalytic production of propylene from bioethanol has gained significant attention recently as a renewable alternative to conventional technologies. This review will discuss the state-of-the-art on the use of catalytic materials, such as zeolites and transition metals, in catalytic conversion of bioethanol to propylene and related reactions. The corresponding mechanisms are reviewed with emphasis on the possibilities provided by these materials to develop alternative processes for selective production of propylene and other olefins from bioethanol. Important aspects such as catalyst texture and architecture, the impact of promoters and co-feeding water on ethanol to propylene reaction and fundamental understanding of reaction mechanisms involved in ethanol dehydration reaction are discussed accordingly.
Pub.: 15 Feb '16, Pinned: 29 Jun '17