Liu Bin, Xing Zebing, Xue Yuxin, Zhang Ji, Zhai Junlin
College of Agricultural Engineering, Shanxi Agricultural University, Jingzhong 030801, China.
Molecules. 2024 Dec 3;29(23):5712. doi: 10.3390/molecules29235712.
The preparation of biochar typically involves the pyrolysis of waste organic biomass. Iron-rich magnetic biochar not only inherits the characteristics of high specific surface area and porous structure from biochar but also possesses significant advantages in easy separation and recovery, which has shown great application potential in various fields such as soil improvement and water resource remediation. This study aims to explore the influence of mineral iron on the carbon sequestration capability of biochar during the pyrolysis process. Experiments were conducted by using spent mushroom substrates as raw materials to prepare biochar at different temperature intervals (300 to 600 °C). The addition of exogenous iron has been found to significantly enhance the carbon retention rate (12.2-44.5%) of biochar across various pyrolysis temperatures and, notably, improves the carbon stability of biochar at 300 °C, 400 °C, and 600 °C. Through the analysis of thermogravimetric mass spectrometry (TG-MS) and X-ray photoelectron spectroscopy (XPS), we discovered that iron catalyzes the thermochemical reactions and inhibits the release of organic small molecules (C-C) through both physical blocking (FeO) and chemical bonding (C=O and O-C=O). The results of Raman spectroscopy and infrared spectroscopy analyses indicate that the addition of iron significantly promotes the graphitization process of carbon and enhances the thermal stability of biochar within the temperature range of 300 to 500 °C. When exploring the retention and stability of carbon during pyrolysis, it was found that under the conditions of 600 °C and the presence of iron, the maximum carbon sequestration rate of biochar can reach 60.6%. Overall, this study highlights the critical role of iron and pyrolysis temperature in enhancing the carbon sequestration capacity of biochar.
生物炭的制备通常涉及废弃有机生物质的热解。富铁磁性生物炭不仅继承了生物炭高比表面积和多孔结构的特点，还在易于分离和回收方面具有显著优势，在土壤改良和水资源修复等各个领域展现出巨大的应用潜力。本研究旨在探讨热解过程中矿物铁对生物炭固碳能力的影响。实验以废弃蘑菇培养料为原料，在不同温度区间（300至600℃）制备生物炭。研究发现，添加外源铁能显著提高不同热解温度下生物炭的碳保留率（12.2 - 44.5%），尤其在300℃、400℃和600℃时提高了生物炭的碳稳定性。通过热重质谱（TG-MS）和X射线光电子能谱（XPS）分析，我们发现铁通过物理阻挡（FeO）和化学键合（C=O和O-C=O）催化热化学反应并抑制有机小分子（C-C）的释放。拉曼光谱和红外光谱分析结果表明，添加铁显著促进了碳的石墨化过程，并在300至500℃温度范围内提高了生物炭的热稳定性。在探索热解过程中碳的保留和稳定性时发现，在600℃且有铁存在的条件下，生物炭的最大固碳率可达60.6%。总体而言，本研究突出了铁和热解温度在提高生物炭固碳能力方面的关键作用。
