(567ba) Evaluation of Membrane Fouling Mechanisms for Separations Applications within a Lignocellulosic Biorefinery

Leberknight, J. M., South Dakota School of Mines and Technology
Menkhaus, T., South Dakota School of Mines and Technology
Gautam, A., South Dakota School of Mines and Technology

The development of economical alternative liquid fuel sources, produced from renewable lignocellulosic biomass, is currently undergoing rapid expansion. As scientific breakthroughs are occurring within the overall process, new technology for recovering and purifying the products from the unique matrix of impurities present in the biomass feedstock production streams will be equally important. Membrane separations can be used in several locations within a biorefinery and offer tremendous potential to reduce water requirements, decrease energy consumption, simplify purification operations, and offer valuable co-products. A major design consideration in filtration operations is membrane fouling and the resulting reduction in membrane flux. Fouling can be caused by a variety of mechanisms (e.g., complete pore blockage, intermediate pore blockage, pore constriction, and/or cake or gel formation), which can be caused by a variety of interactions between solution components and the membrane material. Here we present results discussing membrane fouling tendencies within a pine wood to ethanol process where membrane microfiltration has been used to clarify both the pine wood hydrolysate as well as the crude fermentation broth. Measureable properties of the membrane and foulants such as ionic charge, hydrophilicity, size, and surface roughness have been correlated to membrane fouling tendencies. Empirical models using variable concentrations of fouling components and quantitative membrane properties have been established to predict properties for engineering advanced membranes specifically designed for lignocellulosic biorefinery applications.