Mass transfer in membrane contactors for separating levulinic acid, formic acid, and furfural from biomass hydrolysate with physical organic solvents

Levulinic acid (LA), formic acid (FA), and furfural were separated from an aqueous solution using membrane contactors with organic solvents. The aqueous mixture, simulating LA production's biomass hydrolysate from, contained 7 ​% LA, 3 ​% FA, and 4 ​% FF by weight. The mass transfer coefficients of solutes followed the order: methyl isobutyl ketone (MIBK) ​> ​toluene > 2-propanol > 1-octanol, while solute extraction followed FF ​> ​FA ​> ​LA. FF extraction was more dominated by the resistance of aqueous phase compared to other solutes. The membrane mass transfer resistances could not be neglected and affected the overall mass transfer performance. Using the membrane contactor could improve the FF selectivity compared to an equilibrium extraction technique. The FA selectivity over LA was investigated and a reactive organic solvent such as Aliquat336 in MIBK as well as replacing the organic phase with another aqueous phase enhanced the FA selectivity.