Development of Li(I) Selective Polymeric Adsorbent Prepared by Surface Template Polymerization for Lithium Recovery from Seawater

为了开发从海水中回收Li(I)的工艺，我们尝试用表面模板聚合法制备Li(I)选择性聚合物吸附剂。该技术利用β-二酮和中性有机磷化合物与W/O和W/O/W乳剂的协同作用制备了聚合物吸附剂。Li(I)在W/O和W/O/W乳剂的油水界面与含氟β-二酮和氧化三辛基膦形成配合物，并在以二乙烯苯为交联剂的油相后，将Li(I)配合物印迹于有机树脂表面，在W/O和W/O/W乳剂中聚合。高分子吸附剂对目标物Li(I)的吸附能力高于Na(I)。特别地，利用W/O/W乳液，通过表面模板聚合制备了球形高分子吸附剂。我们还合成了磷酸盐-苯基取代β-二酮缀合物作为Li(I)的新型双功能萃取剂。研究了共轭物对Li(I)的萃取平衡。发现它们的烷基链长度对锂的萃取有重要影响。此外，还对其分布和界面吸附平衡进行了研究。结果表明，共轭物在有机水溶液中的分布和界面吸附平衡常数受其烷基链长度的影响，且共轭物单位摩尔所占的界面面积与其烷基链长度成正比。我们将合成新型含氟双功能萃取剂，并用该萃取剂制备Li(I)选择性聚合物吸附剂，以获得对Li(I)的高吸附能力。

We have tried to prepare the Li(I) selective polymeric adsorbent by a surface template polymerization in order to develop a recovery process of Li(I) from seawater. The polymeric adsorbent were prepared by this technique utilizing a synergistic effect of a β-diketone and a neutral organophosphorus compound with W/O and W/O/W emulsions. Li(I) forms a complex with a Fluorine-containing β-diketone and trioctylphosphine oxide at the oil-water interface of W/O and W/O/W emulsions, and the Li(I) complex was imprinted on the surface of organic resins after the oil phase, in which divinylbenzene was used as the cross-linking agent, in the W/O and W/O/W emulsions was polymerized. Our polymeric adsorbents exhibited high adsorption ability towards target Li(I) over Na(I). Especially, a spherical polymeric adsorbent was created by a surface template polymerization utilizing W/O/W emulsion.We also synthesized the phosphinate-phenyl substituted β-diketone conjugates as novel bifunctional extractants for Li(I). The extraction equilibrium of Li(I) with the conjugates was investigated. It was found that their alkylchain length played an important role in lithium extraction. Furthermore, distribution and interfacial adsorption equilibria were examined. We found that the equilibrium constants of distribution and interfacial adsorption of the conjugates between organic and aqueous solutions were affected by their alkylchain length, and the interfaciaal area occupied by unit mole of the conjugates were proportional to their alkylchain length.We will synthesize new fluorine-containing bifunctional extractants and prepare the Li(I) selective polymeric adsorbents with the new extractants to achieve high adsorption ability towards Li(I).