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Adsorptive removal of fermentation inhibitors from concentrated acid hydrolyzates of lignocellulosic biomass

Sainio, Tuomo, Turku, Irina, Heinonen, Jari
Bioresource technology 2011 v.102 no.10 pp. 6048-6057
acetic acid, activated carbon, adsorption, biomass, cation exchange resins, ethanol, fermentation, hydroxymethylfurfural, lignocellulose, polymers, sorption isotherms
Adsorptive purification of concentrated acid hydrolyzate of lignocellulose was investigated. Cation exchange resin (CS16GC), neutral polymer adsorbent (XAD-16), and granulated activated carbon (GAC) were studied to remove furfural, HMF, and acetic acid from a synthetic hydrolyzate containing 20wt.% H₂SO₄. Adsorption isotherms were determined experimentally. Loading and regeneration were investigated in a laboratory scale column. GAC has the highest adsorption capacity, but regeneration with water was not feasible. XAD-16 and CS16GC had lower adsorption capacities but also shorter cycle times due to easier regeneration. Productivity increased when regenerating with 50wt.% EtOH(aq) solution. To compare adsorbents, process performance was quantified by productivity and fraction of inhibitors removed. GAC yields highest performance when high purity is required and ethanol can be used in regeneration. For lower purities, XAD-16 and GAC yield approximately equal performance. When using ethanol must be avoided, CS16GC offers highest productivity.