Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China.
Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China.
Sci Total Environ. 2022 Sep 10;838(Pt 2):156081. doi: 10.1016/j.scitotenv.2022.156081. Epub 2022 May 20.
Biochars have been highlighted as a means of carbon sequestration, which is significant for achieving carbon neutrality. Mixtures of wood chips and either bentonite or kaolin were co-pyrolysed at temperatures of 350 °C and 550 °C, and the microstructural characteristics and the carbon sequestration potential of the resultant biochar were explored in the study. The addition of minerals promoted the formation of a stable carbon structure in biochar, especially the proportion of SiC bonds in the high-temperature mineral-composited biochar increased by 3.56-3.82 times compared with the original biochar. After bentonite or kaolin was added to wood chips pyrolysed at 550 °C, the carbon loss after HO oxidation was reduced to no more than 19.2%, and the Recalcitrance Index (R) of biochar increased to no less than 0.89. The combined action of high temperature and minerals promoted the formation of highly aromatic structures of biochar (H:C < 0.4) and reduced the amount of dissolved organic carbon to 4.89 mg g. Furthermore, minerals directly covered the surface of biochar, and the content of SiC bond increased, thus strengthening the chemical and thermal stability of biochar. However, the addition of minerals had no significant effect on the biological stability of biochar. The study indicates that the pre-pyrolysis mineral addition is an effective way to increase the carbon sequestration potential of biochar.
生物炭作为一种碳固存手段备受关注，对于实现碳中和具有重要意义。本研究在 350°C 和 550°C 温度下共热解木片和膨润土或高岭土的混合物，探索了所得生物炭的微观结构特征和碳固存潜力。矿物质的添加促进了生物炭中稳定碳结构的形成，特别是高温矿物复合生物炭中 SiC 键的比例比原始生物炭增加了 3.56-3.82 倍。在将膨润土或高岭土添加到 550°C 热解的木片中后，HO 氧化后的碳损失减少到不超过 19.2%，生物炭的抗降解指数（R）增加到不低于 0.89。高温和矿物质的共同作用促进了生物炭中高度芳香结构（H:C<0.4）的形成，并将溶解有机碳的量减少到 4.89mg g。此外，矿物质直接覆盖生物炭表面，SiC 键含量增加，从而增强了生物炭的化学和热稳定性。然而，矿物质的添加对生物炭的生物稳定性没有显著影响。该研究表明，预热解矿物质添加是提高生物炭碳固存潜力的有效途径。
