Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China.
Sci Total Environ. 2011 Sep 15;409(20):4449-55. doi: 10.1016/j.scitotenv.2011.07.016. Epub 2011 Aug 6.
In this study, the pyrolytic behaviors and the thermal-oxidation decomposition characteristics of organic carbon (OC), pyrolytically generated elemental carbon (PEC) and black carbon (BC) particles have been studied in inert and air atmosphere respectively, in order to develop a new PEC correction method for the determination of BC by using thermal oxidation method. Our results indicated that: 1) a part of OC can be removed by heating it at 400°C in inert atmosphere and another part of OC was charred to form PEC, whereas, the weight of BC particles approximately keeps no change in the same conditions. 2) PEC and BC began to decompose at a similar temperature in air atmosphere. However, the decomposition rate of PEC is quite different from that of BC in air atmosphere and the difference varied with the temperature. As maximum, the decomposition rate of PEC is 5.64 times faster than that of BC particles at 500°C in air atmosphere. Based on the difference of the decomposition rate between PEC and BC, a new method of PEC correction was developed for the thermal oxidation method. With the help of the new PEC correction method and thermal analyzer, we successfully determined OC and BC concentrations in actual soot sample and artificial soot samples. The results obtained with our PEC correction method are consistent well with the real value or those analyzed with thermal-optical method, suggesting that the novel PEC correction method have a high accuracy.
在这项研究中，分别在惰性气氛和空气气氛下研究了有机碳（OC）、热解生成的元素碳（PEC）和黑碳（BC）颗粒的热解行为和热氧化分解特性，目的是开发一种新的 PEC 修正方法，用于通过热氧化法测定 BC。我们的结果表明：1）在惰性气氛中加热至 400°C 时，可以去除一部分 OC，而另一部分 OC 碳化形成 PEC，而 BC 颗粒的重量在相同条件下基本保持不变。2）PEC 和 BC 在空气气氛中以相似的温度开始分解。然而，PEC 在空气气氛中的分解速率与 BC 明显不同，并且这种差异随温度而变化。在空气气氛中 500°C 时，PEC 的分解速率最快可达 BC 颗粒的 5.64 倍。基于 PEC 和 BC 分解速率的差异，我们为热氧化法开发了一种新的 PEC 修正方法。借助新的 PEC 修正方法和热分析仪，我们成功地测定了实际烟尘样品和人工烟尘样品中的 OC 和 BC 浓度。我们的 PEC 修正方法得到的结果与实际值或热光法分析的结果非常吻合，表明该新的 PEC 修正方法具有很高的准确性。
