玉米秸秆纳米纤维素制备的工艺优化

Optimization of Preparation Process of Corn Stalk Nanofibrillated Cellulose

摘要:

该研究采用弹射式蒸汽闪爆法（High density steam flash-explosion，HDSF）制备玉米秸秆纳米纤维素纤维，研究蒸汽闪爆压力、蒸汽闪爆时间、NaOH浓度对玉米秸秆中的半纤维素、纤维素、木质素含量的影响。以单因素试验为基础，根据中心组合实验设计原理，将纳米纤维素含量作为响应值，通过响应面分析法进行试验设计与数据分析。试验发现：弹射式蒸汽闪爆法制备纳米纤维素的工艺参数为：蒸汽闪爆压力值为1.5 MPa，蒸汽闪爆时间为285 s，氢氧化钠浓度为0.4 mol/L，纳米纤维素含量预测值46.02%，实验验证值为45.88%，与预测值接近，说明预测模型可靠性较高，此时半纤维素含量13.50%，木质素含量11.78%，证明方法合理可行。影响纳米纤维素得率的因素依次为蒸汽闪爆压力值>蒸汽闪爆时间>氢氧化钠浓度。弹射式蒸汽闪爆法有利于分离相互缠绕的半纤维素、纤维素、木质素，具有效率高、成本低、绿色无污染等优点。并且运用此方法制备的纳米纤维素具有较小粒径和良好的水溶性，这使得玉米秸秆纳米纤维素拥有更好的应用前景。

Abstract:

The effects of steam-flash time, steam-flash pressure, and sodium-hydroxide concentrate on the hemicellulose, cellulose, and lignin contents of corn stalks were studied in this study using the high density steam flash-explosion (HDSF). Based on single-factor experiments and the central-combination-experiment principle of design, the nanofibrillated-cellulose content was taken as the response value, and the experiment’s design and data analysis were carried out using response-surface analysis. The study found that the optimal process for preparing nanofibrillated cellulose was 1.5 MPa, 285 s, and a sodium-hydroxide concentration of 0.4 mol/L, the pentose yield was 45.88% under optimal conditions, close to the predicted value of 46.02%. The results indicated that the surface methodology was appropriate during this process, the hemicellulose content was 13.50% and the lignin content was 11.78%. The factors affecting the yield of nanocellulose were in order of steam-flash pressure> steam-flash time> sodium-hydroxide concentrate. HDSF aids the separation of the entwined hemicellulose, cellulose and lignin, which has advantages of high efficiency, low cost, green and non-pollution, etc. The nanofibrillated cellulose prepared using this method had a small particle size and good water solubility, giving corn nanofibrillated cellulose good prospects for application.