两种胶原纤维固化单宁对La^(3+)的吸附特性研究

Adsorption Property of Tannins Immobilized by Collagen Fiber on La^(3+)

以皮胶原纤维为基质,通过交联剂分别将黑荆树单宁和杨梅单宁固化在胶原纤维上制备吸附材料。实验表明,这两种吸附材料对稀土金属离子La3+有很好的吸附作用。在pH为4.5的条件下,当吸附剂用量为0.1 g,La3+初始浓度为9.952 mmol.L-1,固化杨梅单宁的平衡吸附量为0.388 mmol.g-1,比固化黑荆树单宁略大,其吸附平衡均符合Freundlich方程。进一步研究了固化杨梅单宁的吸附动力学、温度、pH值等对吸附平衡的影响。结果表明,温度对吸附平衡的影响不明显;pH值对吸附平衡有较大影响,在适当范围内提高pH值会增加平衡吸附量;吸附动力学可用拟二级速度方程来描述。当吸附温度为293 K时,由拟二级速率方程计算所得的平衡吸附量与实测的平衡吸附量误差在3%以内。同时固化杨梅单宁也具有良好的柱动力学特性。

Using collagen fiber as matrices, the immobilized tannins adsorbents based on black wattle tannins （IBWT） and myrtan tannins （IMT） were prepared through crosslinking reaction. Experiments showed that adsorption isotherms of IMT and IBWT for La^3＋ could be described by Freundlich model, and their adsorption capacity was higher for La^3＋ . Under pH value 4.5 conditions, the equilibrium capacity of La^3＋ on the IMT was 0. 388 mmol·g^-1 when adsorption process was undertaken by using 0.1 g IMT and 100 ml La^3＋ solution with initial concentration 9. 952 mmol· L^-1. Furthermore, adsorption characteristics of immobilized myrtan tannin that has higher thermal stability were investigated in details. It was found that influence of temperature on adsorption isotherms was not obvious. Otherwise, effect of pH value was significant. Higher pH value of solution led to higher equilibrium adsorption capacity. Data of adsorption rate could be well fitted by pseudo-second-order rate model, and adsorption capacity calculated by the model was consistent with actual measurement. It indicated that the immobilized myrtan tannin had excellent properties of column adsorption kinetics, as well as highly effective availability of adsorption column.