Removal and recovery of acetic acid and two furans during sugar purification of simulated phenols-free biomass hydrolysates

- High removal percentage of furfural was obtained by solvent extraction with n-hexane.
- Acetic acid was selectively removed and enriched by ELM using a basic extractant.
- Adsorption data of HMF onto L-493 was fitted to Freundlich isotherm model well.
- HMF was desorbed well from saturated L-493 adsorbent using aqueous ethanol solution.
- A cost-effective five-step sugar purification process was successfully developed.

A cost-effective five-step sugar purification process involving simultaneous removal and recovery of fermentation inhibitors from biomass hydrolysates was first proposed here. Only the three separation steps (PB, PC and PD) in the process were investigated here. Furfural was selectively removed up to 98.4% from a simulated five-component hydrolysate in a cross-current three-stage extraction system with n-hexane. Most of acetic acid in a simulated four-component hydrolysate was selectively removed by emulsion liquid membrane, and it could be concentrated in the stripping solution up to 4.5 times its initial concentration in the feed solution. 5-Hydroxymethylfurfural was selectively removed from a simulated three-component hydrolysate in batch and continuous fixed-bed column adsorption systems with L-493 adsorbent. Also, 5-hydroxymethylfurfural could be concentrated to about 9 times its feed concentration in the continuous adsorption system through a fixed-bed column desorption experiment with aqueous ethanol solution. These results have shown that the proposed purification process was valid.