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，我们尝试通过表面模板聚合制备Li（I）选择性吸附剂。利用β-二酮和中性有机磷化合物的协同作用，采用W/O和W/O/W乳液制备了高分子吸附剂。在W/O和W/O/W乳液的油-水界面上，Li（I）与含氟β-二酮和三辛基氧化膦形成络合物，以二乙烯基苯为交联剂，使W/O和W/O/W乳液中的油相聚合后，将Li（I）络合物印迹在有机树脂表面。我们的聚合物吸附剂对目标Li（I）表现出高于Na（I）的吸附能力。特别地，我们利用W/O/W乳液通过表面模板聚合制备了球形高分子吸附剂，并合成了新型的次膦酸酯-苯基取代的β-二酮共轭物作为锂离子的双功能萃取剂。研究了络合物对Li（I）的萃取平衡。结果表明，烷基链长对锂的萃取起着重要作用。此外，分布和界面吸附平衡进行了研究。我们发现，共轭物在有机溶液和水溶液之间的分配平衡常数和界面吸附平衡常数受其烷基链长度的影响，我们将合成新型的含氟双功能萃取剂，并制备Li（I）选择性聚合物吸附剂与新的萃取剂，以实现对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).