(395aq) Recovery of Phenolic Compounds From Pyrolysis Wastewater By Adsorption to Kenaf: Comparison of Different Kenaf Pre-Treatments

Holmes, W. E., University of Louisiana at Lafayette
Revellame, E. D., Mississippi State University
Hernandez, R., University of Louisiana at Lafayette
Buchireddy, P., University of Louisiana at Lafayette

There are many chemical and physical processes available for the removal of organic compounds from waste waters.  To enhance the sustainability, energy efficiency, and yield of biofuel production processes it is desirable to recover and use these compounds  using renewable raw materials.  In this study we have used a plant material, Kenaf (Hibiscus cannabinus) for adsorption of small molecular weight phenolic compounds and poly aromatic hydrocarbons generated during the pyrolysis of biomass and contained in the waste water stream.  Several pre-treatments of Kenaf were evaluated ranging from simple water washing to Ozone treatment or torrefaction.  Torrefaction is gaining attention as an option to improve physical properties of physical and chemical properties of biomass prior to pyrolysis or gasification. This process could also increase the surface area, porosity and selectivity of biomass for adsorption applications.    Kenaf was heated slowly  in a reduced environment to a maximum temperature of approximately 200 - 300°C. This process can be considered a mild pyrolysis as it occurs at lower temperatures than normal pyrolysis process.  The result of torrefaction of Kenaf are compared to other pre-treatments (e,g, ozonation, and washing).  Carbon black was used as a positive control, since it is a commercially established adsorption technology and can remove up to 98% of phenol from waste water.  Comparisons are based on mass reduction of organics in the waste water   The resulting organic laden-Kenaf could be used within the pyrolysis process as an additional feedstock, resulting in a close system for wastewater treatment and an enhanced yield of fuels from biomass.