电子垃圾拆解废气中PBDEs特征与污染控制效果

Emission characteristics and pollution controlling efficiency of Polybrominated Diphenyl Ethers(PBDEs)in exhausted gases from dismantling processes of electronic waste

本研究选取某电子垃圾集中拆解园区为对象,对采用的加热烤板和火法冶炼等典型拆解工艺产生的废气以及经不同净化处理系统排放废气中PBDEs的排放水平及其组成特征进行了研究,并进一步分析了各净化处理系统对PBDEs的控制效果.结果表明:加热烤板和火法冶炼拆解过程PBDEs浓度水平差别较大,其顺序为:电热炉二期(68210±12588)ng/m^(3)>滚板炉(10420±1785)ng/m^(3)>电热炉一期(9960±919)ng/m^(3)>火法冶炼(53±14)ng/m^(3).经净化处理系统后废气中PBDEs的排放浓度水平也具有一定差别,其顺序为:2号净化系统(1754±551)ng/m^(3)>1号净化系统(1630±344)ng/m^(3)>3号净化系统(1220±51)ng/m^(3)>4号净化系统(9.5±1.1)ng/m^(3).对不同拆解过程PBDEs组成特征分析发现,采用加热方式进行拆解的电热炉一期、电热炉二期和滚板炉废气PBDEs组成特征相似,以低溴代的BDE-99和BDE-47为主(两种单体质量分数之和均在60%以上),以高温燃烧方式进行拆解的火法冶炼废气则以高溴代的BDE-209为主(质量分数为52%);而不同拆解生产过程产生的PBDEs经4种净化处理系统后的组成特征基本相似,均以低溴代的BDE-28、BDE-47和BDE-99为主(3种单体的质量分数之和均在50%以上).4种废气净化处理系统对PBDEs的总去除率介于82.1%~97.4%,对不同电子垃圾拆解过程产生的PBDEs均具有较好的污染控制效果.

A large number of polybrominated diphenyl ethers(PBDEs)could be emitted from dismantling e-wastes,which might result in potential impacts on the ecological environment and human health.A centralized e-waste dismantled park was selected to quantify emission levels and composition characteristics of PBDEs in the exhaust gases emitted from different purification treatment systems and further evaluate the control effects of each purification treatment system on PBDEs.Concentrations of PBDEs in the heating baking plate and pyrometallurgy dismantling processes were quite different,following the order:the electric furnace phase II(68210±12588)ng/m^(3)>the heating rotary plate furnace(10420±1785)ng/m^(3)>the electric furnace phase I(9960±919)ng/m^(3)>pyrometallurgical furnace(53±14)ng/m^(3).Meanwhile,there were also certain differences in PBDEs among four purification treatment systems with a concentration descending order of:purification system II(1754±551)ng/m^(3)>purification system I(1630±344)ng/m^(3)>purification system III(1220±51)ng/m^(3)>purification systemⅣ(9.5±1.1)ng/m^(3).The composition characteristics of PBDEs in the exhaust gases of the electric heating furnace phase I,electric heating furnace phase II and rolling plate furnace dismantled by heating were similar,with low brominated BDE-99 and BDE-47 as two main components(the sum of their mass fractions was equal to above 60%),the pyrometallurgical waste gas dismantled by high-temperature combustion was dominated by highly brominated BDE-209(mass fraction of 52%);while the composition characteristics of PBDEs produced in the four purification treatment systems were basically similar,all of which were dominated by low-brominated BDE-28,BDE-47 and BDE-99(the mass fractions of three monomers were over 50%).The total removal rate of PBDEs by four exhaust gas purification systems ranged from 82.1%~97.4%,demonstrating good pollution control effects on PBDEs generated by different e-waste dismantling processes.