Separation of acetic acid from the aqueous fraction of fast pyrolysis bio-oils using nanofiltration and reverse osmosis membranes

► Aqueous fraction of bio-oil contains organic acids and valuable hydrocarbons. ► NF/RO membranes should permeate the acids but retain higher hydrocarbons. ► Negative retention of acetic acid and >90% retention of glucose for binary solution. ► Phenolics in full model aqueous bio-oil phase damaged the membranes. ► Separation is feasible but increased membrane flux and chemical stability needed.