Organic Acids and Water Membrane Separations from Bio-Oil

Over 70% of the world’s energy consumption is provided from fossil fuels and with their reserves depleting at a fast rate, alternative energy sources or methods are needed to provide the world’s energy needs. This research hopes to aid with the alternative energy needs by making it economically feasible to produce fuel products, such as bio-diesel, from the upgrading of bio-oil obtained from the pyrolysis of biomass waste material such as sawdust. The high water and oxygenated compound content of the bio-oil make it undesirable for fuel use, but by means of a surface modified commercial membrane we hope to facilitate the separation of desired compounds from others which may be used synthesize other commercially useful products. In this research two methods were used for this separation: electrodialysis and a pressure driven system. Physically modified Nafion 117 nanofiltration pore size membranes were used for the pressure driven system in hopes of separating water and low molecular weight compounds from the bio-oil.  And anion exchange membranes with added polyethylenimine groups to the membrane surface were used to remove organic acids from the bio-oil. The electrodialysis experiments results showed a decrease in conductivity giving supporting belief that some if not all of the organic acids are were removed. And the procedure to widen the Nafion 117 membrane pores also proved to be successful. With Nafion’s proven chemical resistance to the bio-oil, it is expected to achieve the desired separation upon obtaining the appropriate pore diameter of the membrane.