褐藻胶的化学结构与吸附二价金属离子功能关系的研究

IOCAS-IR > 海洋环流与波动重点实验室

	褐藻胶的化学结构与吸附二价金属离子功能关系的研究
	郑乃余
学位类型	博士
	1989
学位授予单位	中国科学院海洋研究所
学位授予地点	中国科学院海洋研究所
学位专业	海洋化学
摘要	本文在测定由中国产海带（Laminaria japonica）、海蒿子（Sargassum pallidum）、海黍子（S.kjellmanianum)和鼠尾藻（s.thunbergii）提取的无损褐藻胶的糖醛酸组成和嵌段结构的基础上，较系统地研究了褐藻酸及其钠盐钙盐对二价金属离子的静态交换平衡特性与褐藻胶结构的关系，初步制成了具有离子交换性能的粒状褐藻酸钙树脂，开对干燥过的褐藻酸、褐藻酸钠和褐藻酸钙在水溶液中的吸附机理进行了探讨和比较。其结果如下：1. 海带、海蒿子、海黍子和鼠尾藻提取的褐藻胶具有不同的组成和嵌段结构，其M/G比值分别为1.86、1.50、1.22和1.27。文中引入结构参数η不胜数= (F_MG))/(F_M * F_G)，η值分别为0.62、0.13、0.36和0.41。后三种马尾藻褐藻胶与海带的结构和性质有差异，而海黍子和鼠尾藻胶在结构与性质方面比较接近。2. 褐藻胶的结构对吸附二坐金属离子具有很大影响，褐藻酸钠Cd-Sr交换反应的分离因子随着M/G比值的增大而增大；褐藻酸钙对Cu~(2+)离子的交换容量随着MG-嵌段比例（或η值）的增大而增大；褐藻酸对Sr~(2+)、Ba~(2+)、Cd~(2+)混合离子的总交换量随着M-嵌段比例的增大而增大。3. 干燥进的褐藻酸、褐藻酸钙以及褐藻酸钠在水溶液中具有不同的吸附机理。褐藻酸钠在溶液中，主要是二价离子诱导G-分子链协同聚合——“蛋箱模型”~(26)，褐藻酸吸附Cu~(2+)、Sr~(2+)时，除了离子交换外，还有使分子链聚合的螯合作作，分子链上未交换的 -COOH可能参与Sr~(2+)的配位，而Cu~(2+)无此现象。褐藻酸钙吸附Cu~(2+)时，可能有部分Cu~(2+)离子进入“蛋箱”内部替代Ca~(2+)离子而重新配位，但“蛋箱”的骨架不变，而吸附Sr~(2+)时，则表现出与离子交换剂截然不同的分子吸附行为。4. 不溶性的褐藻酸和褐藻酸钙具有较高的吸附选择性，尤其是粒状褐藻酸钙树脂的选择性高、稳定性好，可能应用于贵金属的回收、分离与废水处理等。
其他摘要	On the basis of determination of the composition and block-structure of uronate residues in alginates prepared from Chinese brown seaweeds Laminaria japonica, Sargassum pallidum, S.kjellmanianum and S.thunbergii, the correlation between chemical structure and the stalle exchange equilibrium of dried alginic acid, Na-and Ca-alginalos with divatent metal ions aqueous solution have been systematically studied and the mechanism of adsorption exchange have been preliminarily investigated. A new bead ion-exchange resin of calcium alginate has been tentatively prepared and tested. Results obtained may be summarized as follow. 1、The M:g ratio of Na-alginate from four Chinese brown seaweed are 1.06, 1.50, 1.22 and 1.27 for Laminaria japonica, Sargarsum pattidum, S.kjellmanianum and S.thunbergii, respectivety. The sequence distributions of uronate residues in alginate may be illustrative to use a parameter η, defined by η = (F_(MG))/(F_M * F_G) and the η values are 0.62, 0.13, 0.36 and 0.41 for the above-mentioned four species of brown seaweeds, respectively. This indicates that the four alginates are structures of the homopolymeric block type (η < 1). From the M:G ratios and η values it seems that alginate from Laminaria gives the higher value, white the samptes from Sargassum give the lower values. 2、The results show that a close correlation exists between the adsorption of divalent metal ions and the chemical structure of alginates. The selectivity coefficient of Na-alginate for the cadmium-strontium ion exchange reaction tends to increase with increasing of M:G ratio value of alginate, Whereas the exchange capacity of ca alginate with cu~(2+) increases with increasing of the content of MG-block(or η value) in alginate, and the total exchange capacity of alginic acid lends to increase with increasing of the content of M-block in alginate in the aqueous solution of mixed ions S_r~(2+), B_a~(2+) and Cd~(2+). 3、the results show that the mechanism of adsorption exchange of of divalent metal ions by dried alginates are hightly different, depending on both the cation exchanged and the form of alginate. The adsorption mechanism of Na-altinate is the "egg box" model for divalent ion-induced dimerisation of poty-l-guluronate. The adsorption of c_u~(2+) and s_r~(2+) ions by alginic acid is due to both ion exchange and the chelation polymerizing the chain. The -COOH group inexchanged invotes in S_r~(2+) chelation, but does not involve in C_u~(2+) chelation. With the adsorption of C_u~(2+) by Ca-alginate, some C_a~(2+) ions may take the place of C_a~(2+) ions and be coordinated by the carboxyt and hydroxyt groups. The adsorption isotherm indicates that the adsorption of S_r~(2+) by Ca-alginate may be mainly molecular adsorption without cation exchange. 4、The insoluble alginic acid and Ca-alginate, especially bend resin of Ca-alginate have good functions of the adsorption of divalent metal ions, which adsorption functions may be useful for separating and retrieving rare metals or purifying waste water.
页数	76
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/1055
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	郑乃余. 褐藻胶的化学结构与吸附二价金属离子功能关系的研究[D]. 中国科学院海洋研究所. 中国科学院海洋研究所,1989.

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