Abstract:

Platinum group metal (PGM) elements of Pt (platinum), Pd (palladium) is a kind of rare metal elements with high economic value, widely used in industrial, scientific, medical and high-tech fields. Because the mineral supply of PGM cannot meet the growing market demand. The recycling of secondary resources such as waste automobile catalysts and electronic waste has become an important way to alleviate the contradiction between supply and demand of PGM. In this paper, a deep eutectic solvent polymer inclusion membrane electrodialysis integrated system for one-step separation and recovery of Pt(Ⅳ) and Pd(Ⅱ) was constructed by simulating the actual leaching solution of spent automobile catalysts. The effects of various process parameters in the system on the separation of platinum group metals in the leaching solution of spent automobile catalysts were systematically investigated. The results showed that the TOPO/thymol with a molar ratio of 1∶1 had the best transport performance for Pt and Pd. The extraction efficiency of Pt and Pd were 99.90%, and the stripping efficiency were 65.96% and 77.93%, respectively. The 0.05 mol·L^-1 KSCN as the stripping solution had a good separation effect on Pt and Pd, and the stripping efficiency of Pt and Pd were 62.54% and 89.19%, respectively. This study is of great significance for the efficient separation and recovery of Pt(Ⅳ) and Pd(Ⅱ) in spent automobile catalysts.

Key words: separation, membrane, extraction, polymer inclusion membrane, deep eutectic solvent, electrodialysis, platinum group metal

摘要：

铂族金属（platinum group metal，PGM）元素中的铂（platinum）、钯（palladium）是一类具有高经济价值的稀有金属元素，广泛应用于工业、科学、医疗和高科技等领域。由于PGM的矿产供应量无法满足不断增长的市场需求。废旧汽车催化剂、电子废弃物等二次资源的回收成为缓解PGM供需矛盾的重要途径。本研究模拟实际废旧汽车催化剂浸出液，构建分离回收Pt（Ⅳ）、Pd（Ⅱ）的深共晶溶剂聚合物包覆膜电渗析集成体系。系统探究了体系中各工艺参数对模拟浸出液中铂族金属传输与分离的影响。结果表明，摩尔比为1∶1的TOPO/Thy对Pt、Pd传输性能最好，Pt、Pd的萃取效率均为99.90%，反萃取效率分别为65.96%、77.93%。而0.05 mol·L^-1 KSCN作为反萃液对Pt、Pd有良好的分离效果，对Pt、Pd的反萃效率分别为62.54%、89.19%。本研究可为废旧催化剂的处理提供一种高效绿色环保的技术思路与理论依据。

关键词: 分离, 膜, 萃取, 聚合物包覆膜, 深共晶溶剂, 电渗析, 铂族金属