【作者】 华丽；

【导师】 吴懿平；

【作者基本信息】 华中科技大学 ， 材料学， 2008， 博士

【摘要】 电子电气产品中有害物质污染引起了人类高度关注,为此欧盟提出了RoHS指令,将电子电气产品中六种物质——铅、镉、汞、六价铬、PBBs/PBDEs——最大允许浓度值限制在痕量范围(100mg/kg或1000mg/kg)。针对中国电子电气业在遵守RoHS符合性实践中存在的诸多问题,本文采用GC-MS,ICP-OES,UV-Visible分光光度法等,对我国南方和香港地区各类电子电气产品中六种有害物质进行痕量分析,建立了一套标准的六种有害物质初步筛选、萃取、定性、定量分析方法,并对此方法体系的影响因素进行分析,对其相对标准偏差、回复率、再现率、检出限、线性关系等进行评估,得出了优化测试参数,在此条件下其检测的精密度达到或高于国际IEC 62321标准,满足RoHS测试要求。针对六种有害物质仪器分析程序中存在的问题,本文提出了一些解决的新方法。首先,针对光谱分析中背景线漂移、光谱交迭等问题的引发因素如材质效应、外来离子干扰、非目标元素的发射等,提出了如IEC、两点纠正法、多波长选择和SPE在线流动吸附等解决方法;其次,针对PBBs/PBDEs痕量分析过程中PCB、PCN、HCB等干扰,提出了MSPD法,以YMC ODS-C18作为载体进行吸附分离,成功地消除了持久性有机污染物负面影响;再次,针对卤素其它类同系物对溴类阻燃剂分析中的干扰,提出了NICI-和EI-两种GC-MS电离模式并用,可以同时洞察PBBs/PBDEs分子链断裂后阴离子碎片[Br]-, [HBr2]-和分子链段离子碎片[M+2]+,[M+4]+,[M+6]+,[M+8]+的滞留峰,增加了对溴系阻燃剂的选择性;此外,还讨论了EDXRF筛选中试样自身形状、照射面积、照射时间、厚度等因素对激发强度的影响,并对目标元素次级辐射、共存离子散射、吸收等问题提出了参数拟合法进行回归处理,可更准确地获得目标物的谱线强度与检测浓度之间的关系曲线。上述这些方法使分析的精确度和准确性得以提高。超低含量物质的检出限是光谱、色谱分析中的“瓶颈”问题,本文对六价铬、铅、镉的超痕量分析开展研究。选用两种不同吸附剂进行富集处理,即锯屑富集Cr(Ⅵ)和分离Cr(Ⅲ)、MWCNTs富集Pb2+, Cd2+并消除Hg分析中干扰,对过程的影响因素和热力学、动力学参数ΔGο,ΔHο,ΔSο进行研究,结果显示,方法能使目标物浓缩50～100倍,使检出限低至μg/L, ng/L水平。本文还建立了反向神经网络逼近模型,在不改变样本数据空间拓朴结构前提下,将n-D空间样本点映射到2-D平面上并实现对样本数据的搜索寻优,获得了最佳Cr(Ⅵ)萃取和PBB索氏提取条件,此计算结果与真实值之间的误差ξ<0.05%,为实验优化设计提供了理论基础。针对RoHS符合性实践对企业带来的经济负荷,借鉴日本SONY公司绿色化管理理念,提出了绿色“采购——生产——销售”三链环法对电子电气产品进行绿色管理与监控,对我国大陆及香港地区的电子电气业绿色化管理具有指导意义。更多还原

【Abstract】 The threaten of hazardous substances contained in electronic and electrical equipment (EEE) to environment is of high concern, therefore, European Council and Parliament issued the RoHS Directive to restrict the maximal concentration value (MCV) of six substances ? lead (Pb), cadmium (Cd), mercury (Hg), hexavalent chromium (Cr6+), polybrominated biphenyls (PBBs),and polybrominated diphenylethers (PBDEs) ? contained in the new EE products put on the EU market at the trace level (100mg/kg or 1000mg/kg). To comply with the RoHS regulation, EE industries in Hong Kong and China South are facing with great challenges. In this work, GC-MS, ICP-OES, UV-Visible Spectrophotometry were employed to determine the trace concentrations of the above six hazardous substances, and a standard method system for screening primarily, extraction, qualitative and quantitative analyses of the six substances was established and their factors were analyzed. By evaluating the relative standard deviation (R.S.D), recovery, repeatability, limit of detection, linear relation etc., the optimum parameters were given and thus the precision of analysis was equal to or higher than the IEC 62321 standard, meeting the requirement of RoHS.Several methods were proposed to solve the issues in the process of the instrumental analysis on the six hazardous substances. Firstly, by means of interelement correction (IEC), multi-wavelengths, two-point correction, and SPE online flow-injection adsorption method etc., background shift and spectra overlap caused by matrix effect, ambient ion interferences, emission of non-analytes in ICP-OES analysis were eliminated. Secondly, in order to overcome the interferences from PCB, PCN, HCB in the process of determination of PBBs/PBDEs, a matrix solid-phase dispersion (MSPD) method with YMC ODS-C18 as carrier was employed, which completely removed the negative influences of the persistent organic pollutants (POPs). Thirdly, by combining GC-NICI-MS with GC-EI-MS, brominated isomers or ramifications were distinguished from other halogen compounds in which anion fragment retention peaks of [Br]-, [HBr2]- and molecule chain fragment peaks of [M+2]+,[M+4]+,[M+6]+,[M+8]+ were observed simultaneously, and thus the selectivity to brominated retardant flames was greatly improved. Besides, effects of sample shape, thickness, screening area and screening time etc. on X-ray emission intensities of analytes during EDXRF screening were discussed, and in order to eliminate secondary excitation of analytes, absorption, X-ray dispersion of coexisting ions etc., a parameter simulation regression analysis was established, the results showed that a satisfactory function curve between emission intensities and concentration of analytes was obtained. The above means can improve the precision and reliability on the determinations of six hazardous substances.The limit of detection (LOD) on the ultralow substance content is a“bottleneck”of the spectral and chromatographic technologies. The determination of the ultratrace concentration of Cr6+, Pb, Cd were studied by enriching/preconcentrating method with two adsorbents: sawdust and multi-walled carbon nanotubes (MWCNTs). The former was used to enrich Cr(VI) and separate Cr(III), the later was employed to enrich Pb2+, Cd2+ and removal the interference during Hg determination. In order to enhance enrichment efficiency, thermodynamic and dynamic parameters such asΔGο,ΔHο,ΔSοwere discussed. The result showed that the objective content in the sample solutions was concentrated about 50-100 fold, and LOD was minimized toμg·L-1, ng·L-1 level.Furthermore, an optimized imminent model based on back-propagation neural network for experimental data was programmed. The n-D internet relation of sample data can be reduced dimensionly on 2-D plane without loss of real information, and along the trend direction, an optimal point was found out. Using this model to optimize the operational condition of Cr(VI) extraction and PBBs soxhlet extraction, the error (ξ) between simulation and real value was less than 0.05%, which provided a theoretic basis of actual experimental optimization design.Pointing to the economic pressure for RoHS compliance and based on SONY green management system, a“stocking-producing-saling”tri-chain method on supervising the EE products was established, and it is meaningful to guide the green products management of electronic and electrical industries in China Mainland and Hong Kong.更多还原