来源于生物质和煤燃烧产生的soot和charcoal的Py-GC/MS研究

摘要

根据形成机制,黑碳可以分为烟炱(soot)和木炭(charcoal).以稻秆、玉米秆、马尾松和煤为原料分别制备了soot和charcoal两类黑碳,并利用元素分析和热解-气相色谱/质谱联用技术(Py-GC/MS)研究了不同类型黑碳(soot和charcoal)的元素组成和热解特征.结果表明,不同类型黑碳的元素组成具有类似性,均表现为C含量最高,其次为O、H和N.但不同类型黑碳也具有一定的差异,soot黑碳的H/C、O/C、N/C和(O+N)/C原子比均高于charcoal黑碳,表明soot颗粒中含有较多的极性组分.Py-GC/MS分析结果显示,不同类型黑碳裂解产物组成具有一定的类似性,均以芳香化合物为主,还包括含氮化合物、呋喃类化合物、酚类化合物和含硫化合物等,表明黑碳都是以高度芳香性的结构为核心,连接有含氧、氮等杂原子基团等组成.研究还表明,不同类型的黑碳具有各自不同的特征,3种生物质soot样品包含更多的来自燃料本身如蛋白质类、木质素类和多糖类结构信息,而charcoal样品则具有更强的芳香性结构.本研究结果对于理解不同类型黑碳的分子结构和组成具有重要的意义.%Black carbon (BC) was divided into soot and charcoal based on the formation processes.In this study,four representative feedstocks including masson pine,rice straw,corn straw and coal were collected to produce soot-and charcoal-BC materials.Then,these BC materials were characterized by elemental analysis and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS).The results showed that the elemental compositions of different types of BC materials are very similar,with the highest content of carbon,followed by oxygen,hydrogen and nitrogen.However,each BC sample has its distinct properties.The atomic ratios of H/C,O/C,N/C and (O+N)/C were higher for soot samples than charcoal samples formed from the same feedstock,indicating relatively high contents of polar components in soot samples.Py-GC/MS results revealed that the pyrolysis products derived from different BC samples were generally similar,including aromatic compounds,N-containing compounds,furan compounds,phenolic compounds and S-containing compounds.They were all dominated by aromatic compounds,indicating these BC materials were characterized by having aromatic nuclei and linear or branched aliphatic chains,and/or oxygen-,nitrogen -containing units.However,some differences were also observed among these BC materials.The pyrolysis products revealed that biomass soots contain more useful information on original biomass materials such as proteins,lignins and polysaccharides,while charcoals contain higher contents of condensed aromatic structures.The results may be useful for understanding the compositions and molecular structures of different types of BC materials.