玉米秸秆纤维素的磷酸结合碱性过氧化氢分离

Separation of Corn Stover Cellulose by Phosphoric Acid Combined with Alkaline Hydrogen Peroxide

传统玉米秸秆纤维素分离工艺中,一般采用硫酸等强酸进行处理,存在酸腐蚀性强及碱消耗量大等问题。基于此,研究以磷酸预处理结合碱性过氧化氢的处理工艺,探究处理过程中玉米秸秆纤维素、半纤维素及木质素质量分数的变化。通过单因素试验优化得到适宜工艺为:磷酸处理温度150℃,处理时间1. 5 h,磷酸质量分数1. 67%,氢氧化钠质量分数1. 0%,过氧化氢质量分数2. 0%,处理温度50℃,处理时间3 h,在此条件下制备的玉米秸秆纤维素得率达89. 02%,半纤维素去除率达93. 25%,木质素去除率达95. 18%,纤维素质量分数达90. 19%,同时在稀磷酸处理过程获得的滤液中能得到高副加值产物木糖、阿拉伯糖以及糠醛,半纤维素的回收率高达93. 81%。通过FTIR、SEM、AFM和XRD等测试分析发现,玉米秸秆经过磷酸处理后能有效去除半纤维素,碱性过氧化氢处理能脱除木质素组分,两步处理过程中秸秆纤维素晶型无变化,但是结晶度显著提高,热稳定性增强。

In the traditional corn stover cellulose separation process, it is generally treated with strong acid such as sulfuric acid, which has strong acid corrosion and large alkali consumption. Based on this, the treatment of phosphoric acid pretreatment combined with alkaline hydrogen peroxide was studied, and the changes of cellulose, hemicellulose and lignin contents in corn stover during the treatment were investigated. The optimum process was optimized by single factor experiments: phosphoric acid treatment temperature of 150℃, treatment time of 1.5 h, phosphoric acid concentration of 1.67%, sodium hydroxide concentration of 1.0%, hydrogen peroxide concentration of 2.0%, treatment temperature of 50℃, treatment time of 3 h, the yield of cellulose obtained from corn stalk under this condition was 89.02%, hemicellulose removal rate was 93.25%, lignin removal rate was 95.18%, the purity of the cellulose reached 90.19%. Meanwhile, a high secondary value product can be obtained in the filtrate obtained by the phosphoric acid treatment process, including xylose of 68.72%, arabicose of 65.14% and furfural of 30.25%. The characterization of the raw materials and the treated materials showed that the phosphoric acid treatment can effectively remove the hemicellulose and the alkaline hydrogen peroxide treatment can remove lignin components. The cellulose crystal form was not changed, but the crystallinity was increased significantly, and the thermal stability was increased. In addition to obtaining high-purity cellulose, the use of this pre-acid post-base treatment can also give high added value as a by-product of xylose and furfural. The research laid a theoretical foundation for the efficient utilization of corn stover cellulose.