Hydrolysis Of Straw Wtth Acid As Catalyst In Ionic Liquid

Lignocellulose belongs to the most usefull biomass resources, with the features of large stock, easy access, and renewable resources. Lignocellulose biomass resources may become a new generation of energy instead of oil and coal. Fuel ethanol production from lignocellulose can effectively alleviate the energy crisis, in which the key step is to pretreat ligocellulose. In this study, corn straw was selected as raw materials, whose different kinds of pretreatment methods in ionic liquid were designed, combined with acid or cellulase. And the conditions in the process of pretreatment were discussed respectively to obtain the optimal yield of the total reduceing sugar.Firstly, different ways to pretreat corn straw in ionic liquids with traces of water and acid were studyed. The crucial factors, such as different kinds of ionic liquid, heating ways with conventional method or microwave, different acid catalysts, the concentration of acid, the ratio of sraw/[Bmim]Cl, the amount of water supplement, and the temperature were discussed to investigate the effects on the process of pretreatment. The results showed that the optimum experimental conditions were ionic liquid [BMIM]C1as solvent, heating with microwave,0.5%H2SO4as catalyst, the ratio of sraw/[Bmim]Cl0.08:1, water supplement0.25ml·g-1, temperature150℃. Correspondingly, sugar yield was35.5%, which was increased by15.7%, compared to that of core straw pretreated with water as solvent and conventional heating method.Secondly, the hydrochloric acid(concentration>37%)-ionic liquid system at room temperature and atmospheric pressure was established to pretreat straw. The results showed that the sugar rate achieved was only10.5%, while the straw digestion rate was nearly100%. Moreover, the pretreatment only with hydrochloric acid as solvent was studied. The results showed the optimum experimental conditions were temperature at75℃, solid-liquid ratio1:10, the pressure1.5atm, and correspondingly the sugar yield was35.8%. The kinetics of hydrolysis in the acid-ionic liquid system and just in the hydrochloric acid were respectively discussed. The results showed the Ea value has decreased obviously was smaller in the Ionic liquids system with acid as catalyt, which leaded to easier reaction. Finally, the enzymatic hydrolysis of straw pretreated with ionic liquid was studied. The crucial factors, such as temperature, the solid/liquid ratio, pH, and mass of cellulase were discussed to investigate the effects on the reducing sugar production. The results showed the optimum experimental conditions were temperature at50℃, the solid/liquid ratio1:20, pH5.0, the enzyme dosage1:1, corresponding sugar yield was45.7%, while the sugar yield of straw unpretreated with ionic liquid was36.5%.