Metal selectivity of Sargassum spp. and their alginates in relation to their α-L-guluronic acid content and conformation
Metal selectivity of Sargassum spp. and their alginates in relation to their α-L-guluronic acid content and conformation
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DOI：
10.1021/es025781d
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发表时间：
2003-01-15
影响因子：
11.4
通讯作者：
Mucci, A
中科院分区：
文献类型：
--
作者：
Davis, TA;Llanes, F;Mucci, A
本研究描述了从马尾藻褐藻中提取的海藻酸盐中一致和不寻常的均聚物（α - l -古鲁醛酸g块）富集的发现。H-1核磁共振光谱对这些海藻酸盐进行了表征，其均聚古鲁醛酸块（G-block）频率值（F-GG）在0.37 ~ 0.81之间。相对于钠和质子等单价离子以及较小的二价离子（如镁），这些g块的存在导致镉或钙的选择性增强。竞争交换实验结果表明，Cd-海藻酸钙体系的产率选择系数K*(Ca)（Cd）在0.43 +/- 0.10 ~ 1.32 +/- 0.02之间，F-GG为0.23 ~ 0.81。与Cd-海藻酸钙体系相比，mg -海藻酸钙体系和mg -Cd-海藻酸盐体系对从马尾藻（F-GG = 0.81；古巴）和马尾藻（F-GG = 0.75；韩国）中提取的海藻酸盐分别产生最大值K*mg(Ca)（18.0 +/- 1.4）和K*mg(Cd)（16.0 +/- 0.9）。混合金属对藻酸盐体系的选择性研究强调了藻酸盐聚合物的特定大分子构象在决定多金属体系中金属结合行为方面的重要性。此外，他们证明了藻酸盐构象的重要性，因为它发生在马尾藻组织内，决定了这种藻类生物吸附剂的金属结合行为。马尾藻中存在的海藻酸盐的独特组成可能比其他褐藻具有明显的优势，当考虑将其用于从污染和工业废水中战略性地去除有毒重金属时。
The discovery of a consistent and unusual enrichment in homopolymeric (alpha-L-guluronic acid G-blocks in alginates extracted from a suite of Sargassum brown algae is described in this study. H-1 NMR spectroscopy was used to characterize these alginates which display homopolymeric guluronic acid block (G-block) frequency values (F-GG) between 0.37 and 0.81. The presence of these G-blocks results in an enhanced selectivity for cadmium or calcium relative to monovalent ions such as sodium and the proton as well as smaller divalent ions such as magnesium. Results of competitive exchange experiments for the Cd-Ca-alginate system yield selectivity coefficient, K*(Ca)(Cd), values between 0.43 +/- 0.10 and 1.32 +/- 0.02 for a range in F-GG of 0.23 to 0.81. In contrast to the Cd-Ca-alginate system,the Mg-Ca-alginate and Mg-Cd-alginate systems yielded maximum values of K*mg(Ca) (18.0 +/- 1.4) and K*mg(Cd) (16.0 +/- 0.9) for the alginates extracted from Sargassum fluitans (F-GG = 0.81; Cuba) and Sargassum thunbergii (F-GG = 0.75; Korea), respectively. Selectivity studies with mixed-metal pair alginate systems highlight the importance of the specific macromolecular conformation of the alginate polymer in determining metal binding behavior in multiple-metal systems. Furthermore, they demonstrate the importance of the conformation of the alginate as it occurs within the tissue of Sargassum in determining the metal binding behavior of this algal biosorbent. The unique composition of the alginates present in species of Sargassum may represent a distinct advantage over other brown algal species when considering their implementation for the strategic removal of toxic heavy metals from contaminated and industrial wastewaters.