Separation of cadmium from aqueous streams by polymer enhanced ultrafiltration: a two-phase model for complexation binding
Separation of cadmium from aqueous streams by polymer enhanced ultrafiltration: a two-phase model for complexation binding
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DOI：
10.1016/j.memsci.2004.02.034
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发表时间：
2004-08
影响因子：
9.5
通讯作者：
J. Llorens;M. Pujolà;J. Sabaté
中科院分区：
文献类型：
--
作者：
J. Llorens;M. Pujolà;J. Sabaté
采用聚合物增强超滤（PEUF）技术对壳聚糖水溶液中的镉离子进行了脱除。研究了pH和聚合物/金属比的影响。从本质上讲，壳聚糖在中性pH下结合镉离子，但当pH降低时，胺基的质子化导致Cd2+的释放。两相模型，以前开发的可溶性离子交换应用于水软化，适用于络合反应。该模型认为饲料解决方案被分为两个区域。一个区域被聚合物、有界离子和一些水占据；另一个区域是剩余的解。通过对Cd(RNH2)2+和Cd(RNH2)22+形成平衡常数两个参数的估计，可以计算出与实验结果一致的镉截除率。讨论了两相模型相对于单相模型的优点。
The removal of cadmium ions from aqueous solutions where chitosan was present was carried out by polymer enhanced ultrafiltration (PEUF). The effect of pH and polymer/metal ratio was studied. Essentially, chitosan binds cadmium ions at neutral pH, but the protonation of amine groups leads to the release of Cd2+when pH is lowered. A two-phase model, previously developed for a soluble ion-exchange applied to water softening, was adapted for complexation reactions. This model considers the feed solution to be divided into two regions. One region is occupied by the polymer, the bounded ions and some water; the other region is the remaining solution. The estimation of two parameters, the equilibrium constants corresponding to the formation of the complexes Cd(RNH2)2+and Cd(RNH2)22+, allows to calculate cadmium rejections that agree with the experimental ones. The advantage of a two-phase model versus a single-phase one is discussed.