2003—2013年间废旧手机所含金属及其环境特性研究

Metal and Its Environmental Characteristics of Waste Mobile Phones in 2003—2013

科技和经济的发展使手机更新换代速度加快,每年有大量废旧手机产生。目前,废旧手机回收处理主要以"小商贩回收-小作坊处理"为主,该过程环境污染严重。科技的进步以及政策的完善使手机材料发生改变,这些改变带来怎样的环境效应值得研究。为评价废旧手机的重金属及其环境属性随着时间的变化趋势,收集2003—2013年间有代表性的废旧手机样品,采用HClO_4-HF-HNO_3混酸体系消解、美国标准毒性浸出程序(Toxicity Characteristics Leaching Procedure,TCLP)以及引入土壤污染中分析重金属生物有效性的方法,分别分析其金属总量、毒性浸出量和生物有效性,探讨三者随时间变化的规律。结果表明,废旧手机中Fe、Cu、Al质量分数最高,分别为2.42%~4.75%、2.34%~3.37%、1.48%~4.53%;其次Cr质量分数为0.50%~3.65%,Zn为0.018%~6.49%,Ni为0.32%~2.25%;其他金属含量较低。20种金属总量在2003—2013年间先上升后下降,2007年为转折点;另外,Fe、Mo、Ni、Sb和Zn质量分数变化趋势和总量相同,Al和Mg质量分数一直增加,Pb质量分数一直减小,Ba、Co和Cu质量分数变化不大。TCLP结果表明,废旧手机中金属As和Cd未检出,Ag、Ba、Cr和Pb浸出量都没有超过TCLP限值,分别为0.02~0.06、0.88~3、0~0.04、0~2.15 mg·L^(-1),并且TCLP浸出重金属量和该金属在手机中的质量分数存在一定关系。废旧手机中金属生物有效性总和随时间先减小后增加;Al和Mg生物有效性呈上升趋势,Al从2.72 mg·kg^(-1)增加到202.04 mg·kg^(-1),Mg从25.9 mg·kg^(-1)增加到76.12 mg·kg^(-1);Zn、Ba、Fe和Pb呈下降趋势,其他金属生物有效性变化不大。

Development of technology and economic have reduced the usage span of mobile phones,resulting in increase in numberof waste mobile phones(WMPs).Most of the WMPs were treated improperly.During the procedure,the heavy metals in WMPswere release to environment.Additionally,technological innovations changed the materials used in mobile phones.Did this changeshad a positive impact on ecosystems and public health?To explore the impact of time on the WMPs,mainly metals andenvironmental characteristics,typical WMPs generated between2003and2013were collected and its metal contents,leachingcharacteristic and bioavailability were analyzed in detail by digestion with HClO4-HF-HNO3,toxicity characteristic leachingprocedure(TCLP),and methods learn from pollution of soil,respectively.The results show:Fe,Cu,Al in the WMPs is in the rangeof2.42%~4.75%,2.34%~3.37%,1.48%~4.53%,respectively.Cr is0.50%~3.65%,Zn is0.018%~6.49%,Ni is0.32%~2.25%,thelevels of other metals are lower.The total metal content in WMPs increases first from2003to2007then decreases with theproduction year.The concentration of Fe,Mo,Ni,Sb,Zn show a similar trend as the total metals.The concentration of Al and Mgincrease with the production year,while Pb decreases.The concentration of Ba,Co and Cu are stable.TCLP results show that As andCd are not detected and other metals don’t exceed the threshold.Ag,Ba,Cr,Pb leaching concentration is0.02~0.06,0.88~3,0~0.04,0~2.15mg·L-1,respectively.These TCLP leaching concentrations are correlated with their concentrations in WMPs.The sum of allthe metals bioavailability decreases first then increases with time.The bioavailability of Al and Mg increase with time,Al increasesfrom2.72mg·kg-1to202.04mg·kg-1,Mg increases from25.9mg·kg-1to76.12mg·kg-1,while Zn,Ba,Fe and Pb decrease with timeand other metals are hardly changed.