Separation and characterization of hemicellulose, cellulose and lignin from various waste biomass sources

In this study, the potential of different types of biowaste to products with high added value was investigated through a sustainable bio-refinery approach. For this purpose, the pine wood, the walnut shell, the sugar beet pulp, the tea pulp and apricot kernel had been evaluated. In the first step of the study, the effect of chemical structure of biomass on the isolation yields of hemicellulose, cellulose and lignin was investigated. In the second step, the effect of the parameters of the alkali pretreatment process on the insolation efficiency of the main components was investigated. The investigated parameters in the study are the concentration of alkaline, the concentration of peroxide and the contact time. Then in the third step of this study the main components were characterized with instrumental analysis methods and the obtained results were compared with the literature's. FTIR, TGA, H-NMR and XRD analyzes were performed during the characterization step of biomasses and isolated products. It was determined that lignin content of biomass used in this study had no effect on hemicellulose extraction yield but it was effective on lignin yield. The results of chemical analysis of the biomass were determined to be in conformity with the isolation efficiencies of the basic components. The tea pulp's hemicellulose yield (25%) and the walnut shell's lignin isolation yield (19%) were found to be higher than the other biomass types. It was experimentally observed that hemicellulose which was obtained from the apricot kernel was lighter in color than the others. The effect of the alkaline pretreatment parameters was evaluated on the waste of tea pulp and apricot kernel. It was determined that the optimum isolation conditions as contact time: 6 h, alkali concentration: 20 g/L, peroxide concentration: 2-4 %, temperature: 55 ℃. The isolation efficiencies of hemicellulose, cellulose and lignin at optimum conditions (based on raw material) were determined as 36 %, 25 %, 23 % for the pulp of tea and 26%, 34%, 24% for apricot kernel, respectively.