Utilization of statistical analysis and characterization methods in accordance to evaluate structural changes in biomass during pretreatment with aqueous ammonia

Abstract

Pretreatment of biomass prior to use for ethanol production is considered as an important step in increasing efficiency of process. Among various procedures treatment with NH 3 is an effective and facile method for delignification of biomass with high lignin content. Solid cake, utilized in this study is a lignocellulosic biomass with rich organic content. Alternative use of solid cake as a biomass source in ethanol production would be beneficial in reducing the costs of olive oil production. Efficient use of this biomass depend on degradation of its high lignin content and the decrease in its cellulose crystallinity. Hence determination of optimum conditions utilized in NH 3 pretreatment is crucial to achieve economic production ethanol. The pathway in NH 3 treatment of olive oil cake was presented with this study. Solid cake was treated at varying times, NH 3 amounts and temperatures and the changes in biomass structure were determined in terms of lignin content and cellulose crystallinity. Effect of parameters was statistically validated and interpreted in accordance with FT-IR and TGA analyses. Chemical treatment of solid cake resulted in lignin degradation which was followed by consecutive hemicellulose decomposition. Cellulose crystallinity decreased at elevated time intervals due to detoriation of its structure. Results indicated the significance of time especially in decreasing cellulose crystallinity. Lignin degradation was stable in investigated regions and it was concluded that mildest conditions such as low temperature and ammonia (NH 3 ) (%) would have been sufficient to achieve successful treatment provided that the procedure be maintained for long time intervals.