Copper leaching from brake wear debris in standard extraction solutions
Copper leaching from brake wear debris in standard extraction solutions
复制标题
DOI：
10.1039/b303820c
复制
发表时间：
2003-09-01
影响因子：
--
通讯作者：
Schlautman, MA
中科院分区：
文献类型：
--
作者：
Hur, J;Yim, S;Schlautman, MA
采用微波辅助酸消化、联邦毒性特征浸出程序（TCLP）和加州州废物提取试验（WET）对盘式制动器磨屑样品的铜含量和铜浸出进行定量。所测试的制动器磨损碎片是从一种制动衬块源材料的制动器测力计测试获得的复合样品。比较消解研究表明，改进的王水基质（HNO 3：HCl：H2 O2 = 1：3：0.5）优化了测定制动器磨屑中总铜含量的消解效果。根据具有广泛样品质量的子样品的统计学上不可区分的总铜含量结果，未观察到制动器磨屑内的显著样品异质性。合并所有子样品结果后，确定复合制动器磨屑样品的总铜含量为10.8%（g/g），95%置信限为+/- 0.5%（g/g）。在TCLP试验中，铜浸出随固液比的降低而增加，但在WET中不受固液比的影响。对于1：10（4）（g/g）的固液比下，在TCLP和WET期间，复合制动器磨屑样品中存在的总质量的85%和99%的铜分别浸出到溶液中。速率研究还表明，相对于TCLP，WET导致更快的速率和更高程度的铜浸出。与参考含铜材料相比，复合制动器磨屑样品表现出相对较高的TCLP和湿铜浸出特性。制动器磨损碎片样品所表现出的较高的铜浸出可能是由于其较高的比表面积和/或由于在制动过程中发生的铜的化学形式的变化。
Quantification of the copper content of and copper leaching from a disc brake wear debris sample was performed using microwave-assisted acid digestion, the Federal Toxicity Characteristic Leaching Procedure (TCLP), and the State of California Waste Extraction Test (WET). The brake wear debris tested was a composite sample obtained from a brake dynamometer test of one brake pad source material. Comparative digestion studies demonstrated that a modified aqua regia matrix (HNO3 : HCl : H2O2 = 1 : 3 : 0.5) optimized the digestion effectiveness for determining the total copper content in the brake wear debris. No significant sample heterogeneity within the brake wear debris was observed, based on statistically indistinguishable total copper content results for subsamples with a wide range of sample masses. Upon pooling all subsample results, an overall total copper content for the composite brake wear debris sample was determined to be 10.8% (g/g), with a 95% confidence limit of +/- 0.5% (g/g). Copper leaching increased with decreasing solid-to-liquid ratios in TCLP tests, but was unaffected by the solid-to-liquid ratio in the WET. For a 1 : 10(4) (g/g) solid-to-liquid ratio, 85% and 99% of the total mass of copper present in the composite brake wear debris sample was leached into solution during the TCLP and WET, respectively. Rate studies also demonstrated that the WET resulted in a faster rate and higher extent of copper leaching relative to the TCLP. Compared to reference copper-containing materials, the composite brake wear debris sample exhibited relatively higher TCLP and WET copper leaching characteristics. The higher copper leaching exhibited by the brake wear debris sample may have resulted from its higher specific surface area and/or from changes in the chemical form of copper that occurred during the braking process.