Examination of molecular structures of polysaccharides solubilized by thermocatalytic treatment of lignocellulosic materials

hemicellulosic and ligninic fractions of some representative lignocellulosic biomassmaterial during gasification via ?Aqueous Phase Reforming: APR?. Wheat strawand kenaf stalk were selected as the important representatives of variouslignocellulosic material. Both materials were subjected to exhaustive treatments byusing the relevant standart methods to isolate and purify the cellulosic,hemicellulosic and ligninic fractions. Purity of each fraction was tested andconfirmed by comparing the FTIR spectra of the samples produced and the standartsamples received from commercial sources. The structures of each fraction were alsoexamined via SEM and XRD methods. All the fractions obtained from both wheatstraw and kenaf stalk were subjected to APR via two different approaches. While inthe first approach, the materials to be gasified were directly subjected to APRwithout any pretreatment, they were preliminary solubilized in aqueous medium viacatalytic thermal treatment under relatively mild temperature and pressure conditionsand the aqueous solutions containing polysaccharide-derived material weresubjected to APR in the second approach. Direct APR treatment of the cellulosic andhemicellulosic fractions of both the wheat straw and the kenaf stalk gave higheryields of hydrogen when compared with the corresponding results of the secondapproach. Roughly one third of the hydrogen content of the initial cellulose materialwas transferred into gaseous form (H2, CH4, C2H6) while the rest was still in thestructure of the organic products dissolved in aqueous solution. It was shown thatcellulose was the most effective fraction for hydrogen gas production whereas nohydrogen gas was obtained from the ligninic fraction.