Seed-Assisted Synthesis of Magnetic Faujasite-Type Zeolite and Its Adsorption Performance
NANOSCIENCE AND NANOTECHNOLOGY LETTERS
Authors: Hagio, Takeshi; Kunishi, Hiroto; Yamaoka, Keiichi; Kamimoto, Yuki; Ichino, Ryoichi
Abstract
Faujasite-type zeolite (FAU zeolite) is a prospective adsorbent for wastewater treatment. Its large pores not only allow toxic heavy metal cations but also larger harmful organics to enter its structure. It is desirable to apply FAU zeolite in the form of fine particles with a high specific surface area to maximize its adsorption performance; however, the separation of the particles after the treatment is difficult. Therefore, numerous studies are dedicated to preparing composites of zeolites and magnetic particles (magnetic zeolites) to enable their quick and easy separation using magnetic force. Meanwhile, seed-assisted synthesis is a powerful technique for the rapid and selective synthesis of zeolites, although it has not been applied to the fabrication of magnetic zeolites. Here, we report seed-assisted synthesis of magnetic FAU zeolites for the first time, and evaluate its adsorption performance via the adsorption of methylene blue used as a model contaminant. The seed-assisted synthesis provides increased yield of the magnetic FAU zeolite. Moreover, we demonstrate that the magnetic Fe3O4 particles incorporated in the FAU zeolites enable the facile separation of the zeolites from water with the aid of a magnet, while their adsorption performance remains unaffected.
Zeolites for CO2-CO-O-2 Separation to Obtain CO2-Neutral Fuels
ACS APPLIED MATERIALS & INTERFACES
Authors: Perez-Carbajo, Julio; Matito-Martos, Ismael; Balestra, Salvador R. G.; Tsampas, Mihalis N.; van de Sanden, Mauritius C. M.; Delgado, Jose A.; Ismael Agueda, V.; Merkling, Patrick J.; Calero, Sofia
Abstract
Carbon dioxide release has become an important global issue due to the significant and continuous rise in atmospheric CO2 concentrations and the depletion of carbon-based energy resources. Plasmolysis is a very energy efficient process for reintroducing CO2 into energy and chemical cycles by converting CO2 into CO and O-2 utilizing renewable electricity. The bottleneck of the process is that CO remains mixed with O-2 and residual CO2. Therefore, efficient gas separation and recuperation are essential for obtaining pure CO2 which, via water gas shift and Fischer-Tropsch reactions, can lead to the production of CO2-neutral fuels. The idea behind this work is to provide a separation mechanism based on zeolites to optimize the separation of carbon dioxide, carbon monoxide, and oxygen under mild operational conditions. To achieve this goal, we performed a thorough screening of available zeolites based on topology and adsorptive properties using molecular simulation and ideal adsorption solution theory. FAU, BRE, and MTW are identified as suitable topologies for these separation processes. FAU can be used for the separation of carbon dioxide from carbon monoxide and oxygen and BRE or MTW for the separation of carbon monoxide from oxygen. These results are reinforced by pressure swing adsorption simulations at room temperature combining adsorption columns with pure silica FAU zeolite and zeolite BRE at a Si/Al ratio of 3. These zeolites have the added advantage of being commercially available.