State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
Environ Sci Technol. 2022 Oct 4;56(19):13595-13606. doi: 10.1021/acs.est.2c02631. Epub 2022 Sep 14.
Evolution of gaseous contaminants from biomass pyrolysis has drawn increasing attention. However, the thermal degradation, dynamics, and synergetic evolution mechanisms during real-time biomass pyrolysis remain unclear. Herein, a novel method using thermogravimetry-Fourier transform infrared spectrometry-gas chromatography/mass spectrometry (TG-FTIR-GC/MS) combined with thermal kinetics and two-dimensional correlation spectroscopy was proposed to explore the chemical properties and temperature response mechanisms of gaseous species released during (PC) and (TA) pyrolysis. The thermal degradation mechanisms of PC/TA pyrolysis were mainly associated with the sigmoidal rate and random nucleation mechanisms. The formation intensities of alcohols/ethers, phenols/esters, acids, aldehydes, and ketones were higher during low-temperature TA pyrolysis and high-temperature PC pyrolysis. The average carbon oxidation state () of gaseous species mainly ranged from -1.5 to -0.5, and the slope of most gaseous species was greater than -2.0, which was related to the reduction of aldehyde/ketone groups. Two-dimensional (2D)-TG-FTIR-COS analysis revealed that the sequential temperature response of gaseous species followed: acids → phenols, esters → aldehydes → hydrocarbons → alcohols, ethers → aromatics during PC/TA pyrolysis. The establishment of relationships between the sequential response of gases and degraded components provides an important basis for online monitoring/recovery of gaseous contaminants during biomass pyrolysis.
生物质热解过程中气态污染物的演化引起了越来越多的关注。然而，实时生物质热解过程中的热降解、动力学和协同演化机制仍不清楚。本文提出了一种使用热重-傅里叶变换红外光谱-气相色谱/质谱联用（TG-FTIR-GC/MS）结合热动力学和二维相关光谱的新方法，以探索生物质热解过程中释放的气态物质的化学性质和温度响应机制。PC 和 TA 热解的热降解机制主要与 S 形速率和无规成核机制有关。在 TA 低温热解和 PC 高温热解过程中，醇/醚、酚/酯、酸、醛和酮的生成强度较高。气态物质的平均氧化态（）主要在-1.5 到-0.5 之间，大多数气态物质的斜率大于-2.0，这与醛/酮基团的减少有关。二维（2D）-TG-FTIR-COS 分析表明，在 PC/TA 热解过程中，气态物质的顺序温度响应为：酸→酚、酯→醛→烃→醇、醚→芳烃。建立气体与降解组分顺序响应之间的关系，为生物质热解过程中气态污染物的在线监测/回收提供了重要依据。
