探头式超声辅助碱性H_(2)O_(2)处理对蔗渣纤维素影响

Effects on cellulose of bagasse treated by alkaline hydrogen peroxid assisted with probe ultrasound

采用探头式超声辅助碱性H_(2)O_(2)处理蔗渣,探讨NaOH质量分数、H_(2)O_(2)质量分数、反应时间及反应温度对蔗渣纤维素含量和结晶度影响,同时用SEM、FTIR和固体核磁分析处理后蔗渣微观形态结构,并用HPLC测定纤维素、半纤维素和木质素含量。结果表明,NaOH质量分数10%,H_(2)O_(2)质量分数0.9%,反应时间80 min,反应温度200℃,超声功率200 W及超声时间20 min处理蔗渣,纤维素含量(91.63±3.03)%,结晶度(73.08±0.72)%,分别提高45.19%和18.2%;SEM表明蔗渣表面出现沟壑;FTIR表明纤维素特征峰增强,木质素和半纤维素特征峰和固体核磁信号峰减弱。说明探头式超声辅助碱性H_(2)O_(2)较完全降解蔗渣木质素和半纤维素,提高纤维素含量,增加其有效接触面积。

The effects of mass fraction of NaOH,mass fraction of H_(2)O_(2),reaction time and reaction temperature on cellulose content and crystallinity of bagasse treated with alkaline hydrogen peroxide assisted with probe ultrasound were discussed,the microstructure of the treated bagasse were characterized by SEM,FTIR and solid state C NMR spectra,and the contents of cellulose,hemicellulose and lignin of the treated bagasse were determined by HPLC.The results showed that under the optimum conditions(mass fraction of NaOH 10%,mass fraction of HO 0.9%,extracting time 80 min,extracting temperature 200℃,probe ultrasonic intensity 200 W,probe ultrasonic time 20 min),the cellulose content and the crystallinity of the bagasse increased to(91.63±3.03)%and(73.08±0.72)%,which were increased by 45.19%and 18.2%compared with original bagasse.The SEM show that the surface of the bagasse has different depth gullies.The FTIR show that the diffraction peaks of lignin and hemicellulose disappeared,the diffraction peak of cellulose increased,and in the solid state C NMR spectra NMR of bagasse,the signal peaks of lignin and hemicellulose were weakened or even disappeared,which indicated the lignin and hemicellulose in bagasse could be completely degraded by alkaline hydrogen peroxide assisted with probe ultrasound,so the cellulose of the bagasse was exposed,resulted in increases in cellulose content and crystallinity.It is greatly helpful to enhance the cellulose utilization ratio in the subsequent treatment.