New recovery system of novel metals by earth friendly polymer gel/liquid extraction method

我们成功地开发了一种新的回收系统的金（Au），银（Ag），钯（Pd）中包含的电子部分的移动的电话，利用单宁凝胶颗粒。天然缩合单宁是一种普遍存在且廉价的含大量羟基的物质，利用缩合单宁分子进行交联制备单宁凝胶颗粒。详细研究了单宁凝胶颗粒对这些新金属的吸附机理，建立了高分子凝胶/液体萃取法。获得了以下结果。（1）Au、Ag和Pd在单宁凝胶颗粒上的吸附通过Au、Ag和Pd离子还原为单宁凝胶颗粒表面的金属和单宁分子氧化两个步骤进行。（2）金属银的最大吸附容量高达930 mg-Ag/（g-dry-tannin-gel）。少量铜离子的存在加速了银的吸附速率，并在银铜混合物中选择性地回收了银离子。（3）单宁凝胶对Au的吸附容量为8000 mg-Au/g干单宁凝胶。(4)As对于Pd，含Cl较少的Pd物种如PdCl^+和PdCl_2比PdCl_3^-和PdCl_4^-更易吸附在单宁凝胶颗粒上<2->。(5)It阐明了Au和Pd的分离完全取决于Au-Pd水溶液的条件。

We succeeded in developing a novel recovery system of gold(Au), silver(Ag), and palladium(Pd) contained in the electric parts of mobile phones, utilizing tannin gel particles. Tannin gel particles were prepared by cross-linking natural condensed tannin molecules which is ubiquitous and inexpensive material having a lot of hydroxyl groups. The adsorption mechanisms of those novel metals onto the tannin gel particles was investigated in detail to establish the polymer gel/liquid extraction method. The following results were obtained.(1)The adsorption of Au, Ag and Pd onto the tannin gel particles was found to take place through the two steps : the reduction of Au, Ag and Pd ions to the metals on the surface of tannin gel particles and the oxidization of tannin molecules.(2)The maximum capacity of metallic silver adsorbed was extremely high as 930mg-Ag/(g-dry-tannin-gel). The adsorption rate of Ag was accelerated in the presence of small amount of Cu ions and Ag ions were recovered selectively in Ag-Cu mixtures.(3)The tannin gel showed the most highest adsorption capacity (8000mg-Au/g-dry-tannin gel that) for Au among the previous reports.(4)As for Pd, the Pd species containing fewer Cl such as PdCl^+ and PdCl_2, were more adsorbable onto the tannin gel particles than PdCl_3^-and PdCl_4^<2->.(5)It was elucidated that the separation of Au and Pd occurred perfectly depending on the conditions of Au-Pd aqueous solution.