Bio-oil fractionation and upgrading using nanofiltration membranes

Authors: DUARTE, ANDRES - King Abdullah University Of Science And Technology; TOTH, VIKTOR - King Abdullah University Of Science And Technology; SAMARAS, VASILIOS - King Abdullah University Of Science And Technology; Elkasabi, Yaseen; SZEKELY, GYORGY - King Abdullah University Of Science And Technology

Submitted to: Journal Membrane Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/28/2026
Publication Date: 6/8/2026
Citation: Duarte, A., Toth, V., Samaras, V.G., Elkasabi, Y.M., Szekely, G. 2026. Bio-oil fractionation and upgrading using nanofiltration membranes. Journal Membrane Science. https://doi.org/10.1016/j.memsci.2026.125731.
DOI: https://doi.org/10.1016/j.memsci.2026.125731

Interpretive Summary: Farms and forests often produce waste agricultural biomass that imposes financial cost to manage and/or dispose. Pyrolysis is the process of converting waste biomass into crude oils ('bio-oils') using high temperatures. Using bio-oils for fuel or refining into higher value products has often proven difficult due to the unstable and viscous nature of bio-oil. Alternative purification methods are needed that are more effective chemically and financially. We demonstrated the use of membranes for filtering heavier chemical compounds from pyrolysis bio-oil. Specific membranes were more effective and filtering heavier compounds than other types. This work will lead to better utilization of pyrolysis and hence add value to surplus agricultural materials.

Technical Abstract: Bio-oils are a sustainable and cost-effective energy source, but their practical use is limited by their chemical instability, high oxygen content, and elevated viscosity. In this work, we aim to address these challenges through membrane-based upgrading, positioning membranes as an energy-efficient alternative to conventional, energy-intensive fractionation methods. We screened eight commercially available oil-resistant nanofiltration membranes and two in-house fabricated membranes, and explored plasma treatment and polydopamine coating surface modification methods. The complex separation performance of the bio-oil was evaluated using ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry for detailed molecular characterization and comprehensive two-dimensional (2D) gas chromatography time-of-flight mass spectrometry for complementary compound-class analysis of volatile and semi-volatile species. The cross-linked polybenzimidazole membrane removed nearly all compounds above 400 m/z, within an initial bio-oil mass range extending up to ~1000 m/z, and reduced the abundance of highly oxygenated species containing more than 16 oxygen atoms to below 1%.