稻秸皮层硅物质的分布及超微构造  

Distribution and ultrastructure of silica on rice straw surface

作　　者：潘明珠[1] 杜俊[1] 甘习华[2] 吕歆悦 

机构地区：[1]南京林业大学材料科学与工程学院,南京210037 [2]南京林业大学现代分析测试中心,南京210037

出　　处：《农业工程学报》2016年第4期309-314,共6页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金(31300476);全国优秀博士学位论文作者专项资金资助项目(201173)

摘　　要：为了探索稻秸表面硅物质的分布和超微构造,该文以稻秸各皮层的硅物质作为研究对象,采用扫描电子显微镜-能谱分析(scanning electric microscopy coupled with energy-dispersive spectroscopy,SEM-EDS)和X射线衍射仪(X-ray diffraction,XRD)探讨稻秸各皮层硅物质的分布及构造。SEM-EDS研究表明,硅物质主要分布在叶鞘、茎秆的外层,且叶鞘中硅物质的含量高于茎秆。叶鞘外层的硅物质主要以小颗粒物存在、夹杂少量大颗粒物和毛状物。茎秆外层硅物质分布更为均匀,大颗粒物和毛状物进一步减少。叶鞘和茎秆小颗粒物均呈哑铃状规律出现,小颗粒物的粒径约为1μm。XRD研究显示,稻秸的叶鞘、茎秆、节和穗呈现纤维素I型的晶型结构,其结晶度分别为叶鞘55.3%,茎秆59.0%,节47.8%,穗57.4%,内含晶体尺寸约为叶鞘2.10 nm,茎秆2.13 nm,节1.36 nm,穗2.22 nm。稻秸各组织中提取的Si O_2均呈现非晶态特征。研究结果为仿照稻秸纤维-Si O_2结构,诱导纳米无机材料沉积在有机质表面,并且调控纳米颗粒在生长过程中的粒径和形态具有积极的意义。Agricultural residues are annually renewable, widely distributed, and available around the world. Each year, there is around 205 million tons of rice straws produced in China. Rice straw has been traditionally used as organic fertilizer, energy, and raw material for paper and bio-composites. Rice is a typical silicon-accumulating plant. Silica is absorbed in the form of monosilicic acid. Monosilicic acid follows water in the transpiration stream, and finally deposits as an amorphous opal （SiO2）. These amorphous opals are accumulated in cell walls of shoots, intercellular regions, and epidermic cells via biosilicification. Silica in rice plants is considered to be an essential element, although the beneficial effects of silica on growth and yield are partly attributed to the effects of the element on protecting plant from fungal diseases and insects. Furthermore, rice straw is a natural cellulose-SiO2 hybrid nanocomposite. The cell wall could be a matrix for self-assembly of biosilica. Within cell wall, silica is bound in cellulose, hemicellulose and lignin, while SiO2 nanoparticles act as reinforcement partners during the synthesis of such bioinorganic nanocomposites. Bioinorganic hybrid nanocomposites have become well known owing to their unique properties and widespread potential application in different areas, such as catalysis, adsorption, separation, and drug delivery system. In this paper, the sheath, stem, node and ear of rice straw were selected respectively, and the total contents of SiO2 in tissues of rice straw were measured as follows： the weighted test samples were transferred to a crucible, carbonized gently over a burner, and then kept in a muffle furnace. The resulted ash was immersed in hydrochloric acid. The acid-insoluble residue was filtered, washed with hot water until no chlorides were detectable, ignited, and finally SiO2 was obtained and weighted. The distribution of silica on the surface of sheath and stem was investigated with the scanning electron microscopy with energy dispersive

关 键 词：秸秆 硅物质 微观结构 超微构造 扫描电子显微镜-能谱分析 

分 类 号：TK6[动力工程及工程热物理—生物能]