201×7树脂对Fe(CN)_6^(4-)吸附的热力学与动力学

Thermodynamics and kinetics of Fe( CN)_6^(4-) adsorption onto 201 × 7 resin

针对离子交换法处理氰化提金尾液时Fe(CN)4-6的存在引起交换剂的'铁中毒'问题,采用Freundlich、Langmiur、准二级动力学方程以及范山鹰的扩散模型,从热力学与动力学角度研究了201×7树脂对Fe(CN)4-6的吸附特性,并计算了相关热力学常数和表观活化能.结果表明:Fe(CN)4-6在该树脂上的吸附能自发进行,且符合Langmiur方程和准二阶动力学方程,吸附初期表现为膜扩散,后期表现为空隙扩散.扩散到固定层中的Fe(CN)4-6由于被树脂表面的官能团紧紧固定,导致负载树脂在硫酸脱氰过程形成Zn2Fe(CN)6和Cu2Fe(CN)6附着在树脂上,引起树脂的'铁中毒',可通过选择性沉淀先除去Fe(CN)4-6.

To solve the problem of Fe（ CN） ^4-6 causing“iron poisoning” when cyanide-bearing waster water was treated with an ion exchange method, the adsorption properties of Fe（ CN） ^4-6 onto 201 ＆#215; 7 resin were studied by using the Freundlich adsorption equation, the Langmuir adsorption equation, the pseudo-second order equation and the Fan Shan Yang model from thermodynamics and dynamics. The related thermodynamic constant and the apparent activation energy were calculated. The results show that Fe（ CN）^ 4-6 adsorption onto the resin can occur spontaneously. The process conforms to the Langmuir equation and the pseudo-second order equation. It is controlled by film diffusion at the initial stage, but by gap diffusion at the later stage. Fe（ CN）^ 4-6 exchanging to the stern layer is fixed by resin functional groups strongly leading to“iron poisoning” of the resin for generating Zn2Fe（ CN） 6 and Cu2Fe（ CN） 6 which adhere on the resin during the process of cyanides removed from the loaded resin with H2SO4 . Fe（ CN）^ 4-6 in cyanide-bearing waster water can be removed by selective precipitation.