Conrad Kathrine
Department of Plant Biology, Faculty of Life Sciences, University of Copenhagen, Denmark.
Bioresour Technol. 2008 Nov;99(17):8476-84. doi: 10.1016/j.biortech.2007.08.088. Epub 2008 Jun 16.
Plant fibres are capacious for sorption of metal ions, and can be used in water cleaning. Knowledge about the sorption will help in selection of the fibre and optimisation of its chemical modification, if any. The aim of this paper is to investigate the connection, if any, between the distribution of lignin and pectin and the loading of Pb and Zn on coir (mesocarp fibres from Cocos nucifera L.). The coir consisted mainly of xylem and a fibre sheath. The lignin was evenly distributed in the cell walls of the fibre sheath, but in the xylem, there was no detectable content in the compound middle lamella, and a smaller content of lignin in the secondary walls than in the walls of the fibre sheath. The only detectable content of pectin in the fibre sheath walls was in the middle lamella, cell corners and extracellular matrix, while in the xylem, the pectin was almost evenly distributed in the wall, with a higher concentration in the middle lamella and cell corners. All cell walls facing the lacuna had a high content of pectin. The metal ions were mainly loaded on the xylem and cell walls facing the lacuna, maybe with an additional trend to be loaded on the large fibres. Lead was distributed on and across the whole secondary wall. Zinc was loaded on the secondary walls, but there was no information about the distribution across the wall. If there is a simple correlation between the loading of metal ions and the distribution of lignin or pectin, these investigations point at no correlation with lignin and a positive correlation with pectin. It has to be stressed that these conclusions are made on limited material and are therefore preliminary in nature.
植物纤维对金属离子具有较大的吸附容量，可用于水净化。了解这种吸附作用将有助于纤维的选择及其化学改性（如有）的优化。本文的目的是研究木质素和果胶的分布与椰壳纤维（椰子的中果皮纤维）上铅和锌负载量之间是否存在关联。椰壳纤维主要由木质部和纤维鞘组成。木质素均匀分布在纤维鞘的细胞壁中，但在木质部，复合中层中未检测到木质素含量，次生壁中的木质素含量低于纤维鞘壁中的含量。纤维鞘壁中唯一可检测到的果胶含量位于中层、细胞角和细胞外基质中，而在木质部，果胶几乎均匀分布在细胞壁中，在中层和细胞角中的浓度较高。所有面向腔隙的细胞壁都含有高含量的果胶。金属离子主要负载在木质部和面向腔隙的细胞壁上，可能还有一种额外的趋势是负载在大纤维上。铅分布在整个次生壁上并贯穿其中。锌负载在次生壁上，但没有关于其在细胞壁上分布的信息。如果金属离子负载量与木质素或果胶的分布之间存在简单的相关性，这些研究表明与木质素无相关性，与果胶呈正相关。必须强调的是，这些结论是基于有限的材料得出的，因此本质上是初步的。
