Collagen-fiber-immobilized tannins and their adsorption of Au(III)
Collagen-fiber-immobilized tannins and their adsorption of Au(III)
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DOI：
10.1021/ie0340894
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发表时间：
2004-04-28
影响因子：
4.2
通讯作者：
Shi, B
中科院分区：
文献类型：
--
作者：
Liao, XP;Zhang, M;Shi, B
将杨梅单宁和落叶松单宁固定在胶原纤维基质上，制备了对Au（III）具有良好吸附性能的新型吸附剂。当Au（III）初始浓度为478 mg/L，吸附剂用量为20.0 mg时，固定化杨梅单宁和落叶松单宁在303 K时的平衡吸附容量分别为877和784 mg（Au（III））/g。随着温度的升高，吸附容量进一步增加。在323 K下，固定化单宁的平衡吸附容量分别高达1.50 × 10（3）和1.36 × 10（3）Mg-Au（III）/g。固定化单宁对Au（III）的吸附符合Langmuir吸附模型，吸附机理为化学吸附。在不同pH值的缓冲溶液中，Au（III）的吸附等温线也可用Langmuir模型描述，且吸附量随pH值的降低而增大。吸附动力学可以用准二级速率模型来描述，用准二级速率模型计算的吸附量与高温下的实测值接近。结果表明，固定化单宁对Au（III）具有良好的吸附能力，吸附柱的穿透点为223倍床体积。吸附柱中Au（III）的传质系数为3.34 × 10 ~（-5）L/（mg·L ~（-1））。min）。
Novel adsorbents that have an excellent adsorption capacity for Au(III) were prepared by immobilization of bayberry tannins and larch tannins onto collagen fiber matrixes. When the initial concentration of Au(III) was 478 mg/L and the amount of adsorbent was 20.0 mg, the adsorption capacities at equilibrium of immobilized bayberry tannins and larch tannins were 877 and 784 mg(Au(III))/g respectively at 303 K. As the temperature was increased, the adsorption capacities were further increased. At a temperature of 323 K, the adsorption capacities at equilibrium of the immobilized tannins were as high as 1.50 x 10(3) and 1.36 x 10(3) Mg-Au(III)/g, respectively. The adsorption equilibrium data for Au(III) on the immobilized tannins can be well fitted by the Langmuir model, and the mechanism of the adsorption was found to be chemical adsorption. Furthermore, the adsorption isotherms of Au(III) in buffer solutions with different pH values could also be described by the Langmuir model, and the adsorption capacities increased at lower pH values. The kinetics of the adsorption can be well described by a pseudo-second-order rate model, and the adsorption capacities calculated by the pseudo-second-order rate model were close to the values actually measured at higher temperatures. It was found that the breakthrough point of the adsorption column was at 223 bed volumes for the experimental system, indicating that the immobilized tannins have an outstanding ability to concentrate Au(III). The mass-transfer coefficient of Au(III) adsorption in the adsorption column determined by the Adams-Bohart equation was 3.34 x 10(-5) L/(mg(.)min).