超临界CO2中含卤塑料转化炭基功能材料的污染物变化特征研究

The preparation of carbon based functional materials using waste plastics as precursor has been developed as a novel utilization process considering the considerable production of waste plastics. However, the potential generation of more toxic secondary pollutants due to the dissolution and release of halogenated organic pollutants during the preparation process limits the extensive application of this utilization. In view of the unclear illustration on the variation characteristics of pollutants during the process of converting halogenated plastics to carbon based functional materials, the project is designed to identify the dissolution, depolymerization, secondary generation and the migration and transformation mechanisms of pollutants during the process of converting halogenated plastics to carbon based functional materials by supercritical carbon dioxide based on the process control theory of clean production. Taking typical halogenated flame retardants (chlorinated paraffin, tetrabromobisphenol A, brominated epoxy resin) in halogenated plastics from electronic waste as the research object, the dehalogenation properties of typical halogenated organic pollutants in supercritical carbon dioxide will be examined considering the main intermediate products with and without catalyst. The dehalogenation mechanisms of halogenated plastics in supercritical carbon dioxide will be verified depending on the distribution of halogenated compounds. The migration and transformation mechanisms of pollutants during the process of converting halogenated plastics to carbon based functional materials by supercritical carbon dioxide will be clarified. The achievements of this study will lay the scientific foundation and provide powerful technical support for pollution control during the process of converting halogenated plastics to carbon based functional materials.

以废弃塑料为前驱体制备炭基功能材料是一种新型的废弃塑料资源化利用模式，但含卤塑料中卤代有机污染物在材料制备过程中的溶出释放导致的潜在二次污染物的生成严重限制了该资源化模式的应用。针对含卤塑料转化炭基功能材料过程中污染物变化特征阐释不明的研究现状，本项目基于清洁生产过程控制理论，以环境友好的超临界CO2为反应介质对含卤塑料转化炭基功能材料过程中污染物的溶出、解聚、二次合成、迁移转化机理展开研究。以电子废弃物含卤塑料中典型卤代阻燃剂（氯化石蜡、四溴双酚A、溴化环氧树脂）为对象，通过研究有无加入催化剂的脱卤中间产物生成种类，解析不同卤代有机污染物在超临界CO2中的脱卤降解特性；通过探讨含卤化合物在各产物中的分布，揭示含卤塑料在超临界CO2中的催化脱卤机制；阐明超临界CO2中含卤塑料转化炭基功能材料的污染物迁移转化特性，为含卤塑料转化炭基功能材料过程中的污染控制提供理论基础和科技支撑。

本项目结合不同电子废弃物中卤代阻燃剂的存在特点，以电子废弃物含卤塑料中典型卤代阻燃剂（氯化石蜡、四溴双酚A、溴化环氧树脂）为对象，采用环境友好的超临界CO2为反应介质，解析不同卤代有机污染物在超临界CO2中的脱卤降解特性，揭示含卤塑料在超临界CO2中转化炭材料的裂解机制，在卤代有机污染物的脱卤降解以及含卤塑料的资源化处理处置方面具有广阔的应用前景。结果表明，采用NaOH为催化剂，配合低毒聚乙二醇在最佳温度、时间和NaOH添加量为180 ℃，10 h和0.4 g时，可以高效降解反应型溴化环氧树脂并回收线路板；其次，超临界CO2体系是一种有效的含卤塑料脱卤方法，最大脱溴和脱氯效率分别为99.51%和99.12%，自由基反应是超临界流体中聚合物的主要分解机理。相关研究成果发表在Environmental Chemistry Letters，目前另有一篇SCI论文已返修，一篇SCI论文完成撰写，获得此项目资助均为第一标注。