(359d) 3D-Printed ZIF-8 Structured Adsorbents for Biobutanol Recovery

Adsorptive separations using hydrophobic materials are an interesting alternative to traditional unit operations for the recovery of biobutanol. In most industrial applications, product recovery by adsorption is carried out using a fixed-bed of (spherical) adsorbent particles. To improve mass & heat transfer characteristics, the use of particles with a smaller diameter is beneficial. Yet, decreasing the particle diameter also leads to an increase in bed pressure drops, thus limiting the particle diameter which can be used in industrial systems.

The use of adsorbent monoliths allows to uncouple the relationship between mass & heat transfer and bed pressure drop. 3D-printing to synthesize these adsorbent monoliths gives a much larger design freedom, compared to traditional methods. In this contribution, the development of 3D-printed ZIF-8 adsorbent monoliths for the recovery of renewable alcohols will be discussed. Characterization of the monoliths was carried out via X-ray diffraction, infrared spectroscopy, scanning electron microscopy and the measurement of vapor phase alcohol isotherms. The separation efficiency of these monoliths was evaluated via the performance of breakthrough experiments using model fermentation mixtures. The effect of gas velocity on butanol adsorption, as well as the effect of the regeneration temperature on the adsorption cycle time was investigated.