Identifying Selective Adsorbents for the Recovery of Renewable Isobutanol

While many studies have focused on the adsorptive recovery of bioethanol and biobutanol produced via fermentation, few articles have been published on the recovery of renewable isobutanol via adsorption. We have screened over 32 materials for their capacity to recover isobutanol from a dilute mixture. From this screening, we identified two promising activated carbons (F300 and F400) and two polystyrene-divinylbenzene resins (XAD-16 and L-493) with a high isobutanol capacities (0.45 g/g XAD-16, 0.38 g/g L-493, and 0.25 g/g F300 and F400). These materials were further characterized (Ar, vapor, and liquid isotherms), and the effect of different typical fermentation components on the batch uptake of isobutanol was investigated. For the F300 carbon and L-493 resin, only a small decrease in the uptake of isobutanol was observed in the presence of fermentation compounds (0.17 g/g F300, 0.26 g/g L-493). Subsequently, we investigated the separation of an isobutanol/ethanol mixture on a packed column of F300 and L-493. For both materials, the high capacity for isobutanol is retained in dynamic conditions. Therefore, in this work, two promising materials (L-493 and F300) emerge as interesting candidates for the adsorptive recovery of isobutanol.