论文部分内容阅读
为了减少废旧电子塑料带来的环境污染及健康风险,选择柠檬烯为溶剂、正丙醇为反溶剂,调查了从电子塑料溶液沉淀回收聚苯乙烯(PS)过程中溴系阻燃剂的转移行为,讨论了沉淀工艺参数对阻燃剂分离效果的影响规律,确定了分离阻燃剂的沉淀条件.实验结果表明:难溶解的阻燃剂主要通过析出晶体转移到沉淀中,易溶解的阻燃剂通过溶剂携带转移到沉淀中.较高温度或较少正丙醇用量有利于提高十溴联苯醚(DecaBDE)的分离效果;较低温度或较大正丙醇用量有利于四溴双酚A(TBBPA)的分离,高速搅拌能抑制沉淀颗粒团聚、减少沉淀物中的溶剂含量,可同时改善DecaBDE和TBBPA的分离效果.10％的塑料溶液在正丙醇用量为1∶1、40℃及3000 r· min-1的条件下进行沉淀,能获得粒径为0.92mm左右的再生PS颗粒,塑料溶液中90％以上的多溴联苯醚(PBDEs)、95％以上的TBBPA被脱除.“,”To avoid the pollution and health risks from BFRs in waste electronic plastic,d-limonene and npropanol were respectively selected as the solvent and precipitant of plastic in this recycling process.Accordingly,the transfer behavior of BFRs during precipitation and the effects of the precipitation conditions on the removal rate of BFRs were investigated.The experimental results showed that insoluble BFRs migrate into the plastic precipitate through the formation of crystals,while soluble BFRs migrate into the precipitate via the solvent.The removal efficiency of DecaBDE increased at higher temperatures and with a smaller concentration of n-propanol.In contrast,the removal efficiency of TBBPA was greater at lower temperatures with a higher concentration of n-propanol.The results also showed that high-speed stirring suppressed the aggregation of PS particles,which reduced the size of the precipitate particles and decreased the concentration of solvent in the precipitate.When 10％ of the plastic solution precipitated under a 1 ∶ 1 mass ratio of n-propanol to solution at 40 ℃ with stirring of 3 000 r ·min-1,greater than 90％ of the PBDEs and 95％ of the TBBPA in the original plastic solution were removed by this process.