Gotoh Takeshi, Matsushima Keiei, Kikuchi Ken-Ichi
Department of Materials-Process Engineering and Applied Chemistry for Environments, Akita University, 1-1 Tegata Gakuen-Cho, Akita 010-8502, Japan.
Chemosphere. 2004 Apr;55(1):57-64. doi: 10.1016/j.chemosphere.2003.10.034.
The covalently cross-linked alginate gel beads were prepared by the reactions of Ca(2+)-doped alginate gel beads, which were formed by spraying a viscous alginate solution into a calcium chloride solution, with cyanogen bromide and following 1,6-diaminohexane. The cross-linking of alginate matrix decreased the mean bead diameter by about 30% and made the beads durable in some extent under alkaline conditions. The adsorption of metal ions on the covalently cross-linked alginate gel beads was rapid and reached at equilibrium within 30 min at 25 degrees C. Adsorption isotherms of Cu(II), Mn(II), and Ca2+ on the beads possessed a stepwise shape, which was firstly determined by Rorrer et al. [Ind. Eng. Chem. Res. 32 (1993) 2170] for cross-linked chitosan gel beads and explained by a pore-blockage mechanism. Higher selectivity was determined against Cu(II) over Mn(II) and Ca2+, especially at a low concentration region. These metal adsorption profiles for the covalently cross-linked alginate gel beads was almost the same as those for the un-cross-linked beads, indicating that the cross-linking reactions were performed without interfering the adsorption characteristics of alginate gel beads.
通过将粘性海藻酸盐溶液喷入氯化钙溶液中形成的掺钙（Ca(2+)）海藻酸盐凝胶珠与溴化氰及随后的1,6 - 己二胺反应，制备了共价交联的海藻酸盐凝胶珠。海藻酸盐基质的交联使珠的平均直径减小了约30%，并使珠子在一定程度上在碱性条件下更耐用。金属离子在共价交联的海藻酸盐凝胶珠上的吸附迅速，并在25℃下30分钟内达到平衡。Cu(II)、Mn(II)和Ca2+在珠子上的吸附等温线呈阶梯状，这首先由Rorrer等人[《工业与工程化学研究》32 (1993) 2170]针对交联壳聚糖凝胶珠确定，并由孔堵塞机制解释。相对于Mn(II)和Ca2+，对Cu(II)具有更高的选择性，尤其是在低浓度区域。共价交联的海藻酸盐凝胶珠的这些金属吸附曲线与未交联珠子的几乎相同，表明交联反应在不干扰海藻酸盐凝胶珠吸附特性的情况下进行。
