改性剂对超临界萃取塑料中十溴联苯醚的影响

Effect of Modifier on Supercritical Carbon Dioxide Extraction Process of Decabromodiphenyl Ether Contained in Waste Plastics

分析了超临界二氧化碳萃取分离塑料中十溴联苯醚效率不佳的原因,调查了甲苯、柠檬烯、二氯甲烷、乙酸乙酯、甲醇、正丙醇等六种改性剂对超临界CO2萃取分离十溴联苯醚的作用,提出了采用塑料的良溶剂和非溶剂的混合物提高萃取效率的新方法。实验结果表明,采用质量比为2:3的正丙醇与柠檬烯的二元改性体系,当改性剂体积百分比总浓度为15%,在60℃、20 MPa的超临界条件下,连续萃取4 h,电视机外壳塑料的十联苯醚去除率超过95%,九溴联苯醚去除率为100%。

A laboratory experiment was conducted with the purpose to separate decabromodiphenyl ether （DecaBDE）, one of the commonly-used flame retardants, contained in plastics by a supercritical carbon dioxide extraction process, through which reasons of inefficient extraction of DecaBDE from waste HIPS plastic were found and the roles of toluene, d- limonene, diphenylmethane, methanol and n-propanol on the extraction process were investigated. On the basis of the experiment, a method for improving extraction efficiency by use of a kind of mixed solvent as the modifier was developed. The results showed that a suitable mass ratio of n-propanol to d-limonene was 2 ： 3 and total concentration of two-component modifier 15%; and under the condition of 60 ℃, 20 MPa, 4 h of extraction duration, more than 95% of DecaBDE and 100% of nona-bromodiphenyl ether were removed, thus total concentration of DecaBDE residuals in HIPS plastic was reduced to lower than 0.5%.