Roles of microbial acidic polysaccharides in precipitation rate and polymorph of calcium carbonate minerals
Roles of microbial acidic polysaccharides in precipitation rate and polymorph of calcium carbonate minerals
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DOI：
10.1016/j.clay.2011.01.013
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发表时间：
2011-03-01
影响因子：
5.6
通讯作者：
Hwang, Jinyeon
中科院分区：
文献类型：
--
作者：
Kawano, Motoharu;Hwang, Jinyeon
由细菌细胞分泌的有机分子能够影响包括碳酸钙（CaCO 3）矿物在内的各种矿物的溶解和沉淀速率。为了评估多糖对CaCO 3矿物的沉淀速率和多晶型的影响，在含有海藻酸或结冷胶的系统中通过分批方法使用100 ml溶液在25 ℃下进行沉淀实验。每种溶液含有5.0 mM Ca 2+和Mg 2+，以及20.0 mM HCO 3-离子和0.00、0.01、0.05、0.1、0.2和0.5 mg/ml海藻酸（A系统：A1-A5）或结冷胶（G系统：G1-G5）。结果表明，海藻酸和结冷胶都显着抑制碳酸钙矿物的沉淀与多糖浓度的增加。值得注意的是，发现海藻酸的抑制作用比结冷胶的抑制作用大得多。此外，只有文石形成在不含多糖的溶液中，由于镁离子的作用。然而，文石作为一个多晶型物的优势下降，方解石的增加，这两种多糖的浓度增加，和这种效果的多晶型藻酸比结冷胶大得多。这些对沉淀速率和多晶型的影响可能是由方解石和文石表面上的多糖的吸附引起的。然而，较高的电荷密度的海藻酸可能有助于较强的抑制作用的沉淀速率，和相对较高的吸附亲和力的文石表面的多糖也抑制了文石的生长，导致形成的方解石作为一个占主导地位的多晶型。(C)2011 Elsevier B. V.保留所有权利。
Organic molecules secreted by bacterial cells are capable of influencing dissolution and precipitation rates of various minerals including calcium carbonate (CaCO3) minerals. To evaluate the effects of polysaccharides on the precipitation rates and polymorph of CaCO3 minerals, precipitation experiments were performed in systems containing alginic acid or gellan gum by the batch method using 100 ml solution at 25 degrees C. Each solution contained 5.0 mM Ca2+ and Mg2+, and 20.0 mM HCO3- ions with 0.00, 0.01, 0.05, 0.1, 0.2, and 0.5 mg/ml of alginic acid (A systems: A1-A5) or gellan gum (G systems: G1-G5). Results showed that both alginic acid and gellan gum significantly inhibited the precipitation of CaCO3 minerals with increasing concentrations of the polysaccharides. Notably, it was found that the inhibition effect of alginic acid was much greater than that of gellan gum. In addition, only aragonite was formed in solutions containing no polysaccharides, owing to the effect of Mg2+ ions. However, the dominance of aragonite as a polymorph decreased and that of calcite increased with increasing concentrations of both polysaccharides, and this effect on the polymorph was much greater for alginic acid than for gellan gum. These effects on precipitation rates and polymorph are likely caused by the adsorption of both polysaccharides on the surfaces of calcite and aragonite. However the higher charge density of alginic acid may have contributed to the stronger inhibition effects on precipitation rates, and relatively higher adsorption affinity of the aragonite surfaces with the polysaccharides also inhibits growth of aragonite resulting in formation of calcite as a dominant polymorph. (C) 2011 Elsevier B.V. All rights reserved.