基于唐南渗析原理阳离子交换膜对Cu^(2+)、Mn^(2+)、Zn^(2+)去除能力的研究

Research on Removal of Copper,Manganese and Zinc Ions Using Cation Exchange Membrane Based on Donnan Dialysis

基于唐南渗析原理,采用阳离子交换膜去除原水中Cu2+、Mn2+、Zn2+等重金属离子,研究影响阳离子交换膜去除各重金属离子能力大小的机制以及2种重金属离子共存时互相干扰的机制.结果表明,阳离子交换膜可有效去除原水中Cu2+、Mn2+、Zn2+等重金属离子,去除率为75%～85%;在浓度相同下且重金属离子带相同电荷数时,其水化离子半径越小,离子扩散速度就越快,阳离子交换膜对其去除能力就越强;当重金属水化离子半径基本相同时,膜对原子序数小的重金属离子的去除能力更强;相同浓度且相同电荷数的重金属离子共存时,各离子同步被去除,但各离子之间存在干扰,越易于被离子交换的离子与其它离子共存时,其竞争能力越强,使其他离子的去除率降低越多;当待去除离子的总浓度远低于膜的交换容量时,离子共存时各离子的去除率相比离子单独存在时各离子的去除率下降幅度不大.

Based on Donnan dialysis technique,the mechanism that influences the exchange capacity of the membrane and the interaction mechanism between two co-existing ions are investigated in this paper,where the cation exchange membrane is applied to remove the heavy metal ions such as copper,manganese,zinc.The following results were obtained： It is applicable to use the cation exchange membrane to remove copper,manganese and zinc ions and 75%-85% of removal efficiency can be obtained;when the concentration and charge number are the same,the smaller the radius of hydrated heavy metal,the quicker the ion diffuse and consequently the higher removal efficiency the membrane can achieve,which is the main factor;when the radius of the hydrated heavy metals are approximately same,the membrane will have higher removal efficiency to the ion with lower atomic number;when the ions with same charge number and concentration co-exist,both of them are removed but with different removal speeds for existing of disturbance between them and there exist diffusion competition,i.e.those who are more prone to be exchanged will be more competitive and more likely to low the removal rate of the other ion seriously;if the total concentration of the ions is far lower than the exchange capacity of the membrane,the removal efficiency when the ions coexist is not lower too much than that of the case when they exist lonely.