基于离子液体电动力学的废旧印刷线路板覆层金属回收机制及污染物迁移转化规律

At present, electronic waste or e-waste, also called as waste electric and electronic equipment, is one of the most important environmental issues that China is currently faced with. To implement the e-waste pollution control, it is extremely important to develop new, safe, efficient and low cost technologies for waste printed circuit boards (WPCBs) reutilization. Ionic liquids (ILs) aided electrokinetics could efficiently recycle coated metals to nano-metals within one step, providing a new way for WPCBs reutilization. The key to make this new technology practical is the efficiency of recycled coated metals, the amount of coated nano-metals and pollution control. This project uses the characteristics of ionic liquids aided electrokinetics as the core to study the inter-mechanisms between ionic liquids and WPCBs (specifically, coated metals such as Cu, toxic heavy metals such as Pb and Zn, organic pollutents such as brominated flame retardants), to investigae the connections between coated metals and toxic heavy metals and the connections between metals and organic pollutants, to discuss the electrochemical reaction principles and kinetics of the coated metals in the in the electrokinetic system, to analyze the nanomaterials formation mechanisms of the coated metals, and to understand the mechanisms of pollutant emission, formation, migration and transformation. Then, according to these theories, we regulate and optimum the system parameters of ionic liquids aided electrokinetics to ensure the recovery efficiency of coated nano-metals from WPCBs and to achieve zero emission as much as possible. The achievements of the research project will lay the scientific foundation and provide powerful technical support for the engineering applications of ionic liquids aided electrokinetics in e-waste reutilization.

电子废弃物是我国目前面临的重要环境问题之一。开发新型安全高效低耗的废旧印刷线路板（WPCBs）资源化技术对电子废弃物的污染控制具有极其重要的意义。离子液体电动力学技术可以直接在组成极其复杂的WPCBs中回收覆层金属的同时获得附加值极高的覆层金属纳米材料，为其资源化提供了一条新的途径。但如何调控WPCBs这一复杂体系离子液体电动力学过程，以提高覆层金属回收效率及其纳米材料产量、实现全过程污染控制，是该工艺实用化的关键。本课题以WPCBs离子液体电动力学反应特性为核心，研究此体系中离子液体与WPCBs之间相互作用，深入了解Cu等覆层金属在体系中的电化学反应原理、动力学机制及其纳米材料形成机理，探讨体系污染物迁移转化规律，在确保Cu等覆层金属回收效率及其纳米材料产率的基础上，定向调控优化工艺参数，尽可能地实现全过程污染零排放，为该新技术在WPCBs等电子废弃物的进一步研究和应用奠定理论基础。

电子废弃物是我国目前面临的重要环境问题之一。开发新型安全高效低耗的废旧印刷线路板（WPCBs）资源化技术对电子废弃物的污染控制具有极其重要的意义。项目筛选六种离子液体，研究了各环境因素对离子液体浸提WPCBs中铜的影响，利用统计学分析了离子液体浸提过程中铜与重金属铅锌之间的相互影响；构建了硫酸-电动力学资源化回收WPCBs体系，系统研究了各环境因素对此体系WPCBs中金属回收的影响，讨论了电动力学资源化过程中重金属的迁移转化规律；利用离子液体-电动力学法成功从WPCBs制备得到微米、纳米铜。结果表明，离子液体和工业三酸一样，可以实现金属铜的完全浸出，浸出规律也与无机酸类似，但温度展现出相反的规律；动力学研究表明，离子液体体系中，扩散控制占主要因素，而无机酸浸出体系中铜的浸出一般取决于表面反应；具有HSO4- 结构的离子液体对铜的浸出效率要高于具有CF3SO3-结构的离子液体；此外，统计分析表时铜和锌的浸提高度相关，而铅与铜和锌的相关度不大。电动力学法完全可以实现WPCBs中金属的资源化回收，以石墨棒作阳极，钛网作阴极，臭氧1.5 L/min， 300 r/min， CuSO4﹒5H2O (30 g/L) 、 NaCl (40 g/L) 、 H2SO4 (110 g/L)、0.6A下电解9h，金属回收率为96.51%。离子液体[MIm]HSO4替换H2SO4，其对各金属的以及总金属的回收和迁移转化都有一定的影响。金属Cu、Fe、Ni、Sn、Pb和Al的回收率相对较高，其中金属Cu、Ni、Sn和Pb的回收率随着离子液体[MIm]HSO4替换率的增大而降低，而金属Fe和Al的回收率随着[MIm]HSO4替换率的增大先升高后降低。总金属的回收率随着离子液体[MIm]HSO4替换率的增大而降低。硫酸体系下可以制备得到非单晶的枝晶状铜粉，而加入添加剂或离子液体，所得铜粉为单晶纳米颗粒。本项目的研究成果将为电子废弃物电动力学或矿浆电解资源化的工业化应用提供科学数据和理论支持。本课题发表论文17篇，其SCI检索论文11篇，申请国家发明专利8项，培养硕士研究生5人。