关键词: 木质素, 半纤维素, 纤维素, 玉米秸秆

Abstract:

In order to overcome the defects of separation of three components of plant stalk lignin and hemicellulose and cellulose in the high temperature and high pressure harsh conditions and the low purity and recovery rate of separation of the components, this stady was first pretreated the corn stalk  by using of ethanol and nitric acid under atmospheric condition. After that, it was steamed in the dilute alkali solution and treated by H2O2. The optimized scheme of separating and purifying cellulose from corn stalk was provided by the orthogonal test. It included the removal of lignin and hemicellulose in corn stalk. For the lignin its removal rate was 76.3% and recovery rate was 44.5% when solid-to-liquid ratio was 1∶14, the ratio of nitric acid:ethanol was 1∶2 (v/v), and the reaction time was 3 h at 76 ℃. For the hemicellulose its removal ratio was 98.8% when the concentration of the solution NaOH was 4%, solid-to-liquid ratio was 1∶40, temperature was at 95 ℃, and the reaction time was 2.5 h. For the hemicellulose its recovery rate was 66.0% when the ratio of colatuie-to-ethanol was 1∶0.8 (v/v), the settling time was 2 h and pH 7. The content of the obtained cellulose reachs to 99.28% and the yield was 59.7% after being treated for 6 h by 2.5% H2O2 solution at the temperature of (46±1)℃, solid-to-liquid ratio of 1∶30 and pH 11.5. Above result showed that the method had some merits, including mild reaction conditions, environment friendly, and should be a new way of classification using corn stalk.

Key words: lignin, hemicellulose, cellulose, corn stalk