AFM和XPS揭示自催化乙醇法制浆木素沉淀现象与机理  

Lignin Precipitation in Auto-catalyzed Ethanol Pulping Studied by XPS and AFM

作　　者：徐永建[1,2] 张美云[1] 李可成 

机构地区：[1]陕西科技大学造纸工程学院,陕西省造纸技术与特种纸品开发重点实验室,710021 [2]加拿大New Brunswick大学化学工程系,E382L2

出　　处：《中国造纸学报》2009年第1期46-50,共5页Transactions of China Pulp and Paper

摘　　要：研究了乙醇麦草浆纤维表面的形貌学特征、化学组成和木素的分布。AFM研究结果表明,未洗涤乙醇浆纤维表面被无定形的木素完全覆盖,木素颗粒的数量和大小随洗涤逐渐减少减小;洗涤四段的乙醇麦草浆纤维微细纤维清晰可见,但仍然可见木素颗粒。研究还表明,乙醇浆纤维表面木素为球状颗粒,这是木素分子内聚力作用的结果。木素在纤维表面沉积所产生的木素颗粒的大小、分布和形貌学特征与木素性质和浓度有关。XPS分析结果表明,乙醇麦草浆纤维表面O/C比远离纤维素O/C比的理论值而接近木素O/C比的理论值,证明乙醇浆纤维表面存在木素。同时对乙醇浆卡伯值的变化进行了测定,表明快速冷却洗涤法乙醇浆卡伯值高的原因主要是在蒸煮和洗涤过程中溶解木素在纤维表面二次吸附和沉积造成的。The morphological characteristics,chemical composition and lignin distribution on the fiber surfaces of auto-catalyzed ethanol pulp were studied.The results obtained from the observation of AFM showed that lignin particles completely cover on the un-washed fiber surfaces,the amount and size of the lignin particles covered on the fiber surfaces become less and small in washing process.The fibrillar structure can be observed clearly but there still are lignin particles on the fiber surfaces after four-stage washing.It was found that lignin particles on the fiber surface look like globule due to the interaction between lignin molecules.XPS analyses results indicated that O/C ratio of ethanol wheat straw pulp fiber surface is higher than the theoretical O/C ratio of cellulose and close to the theoretical O/C ratio of lignin,and it proves there is lignin on the fiber surface.Kappa number measurement suggested high kappa number of ethanol pulp is mainly due to the precipitation of the dissolved lignin from the pulping liquor.

关 键 词：乙醇制浆 木素沉淀 AFM XPS 麦草 

分 类 号：TS743.9[轻工技术与工程—制浆造纸工程]