Mechanical Engineering Department, Montana Technological University, Butte, MT, USA.
Metallurgical and Materials Engineering Department, Montana Technological University, Butte, MT, USA.
Sci Rep. 2024 Aug 21;14(1):19419. doi: 10.1038/s41598-024-70186-z.
Lignin syringyl to guaiacyl ratio (S/G) has long been suspected to have measurable impacts on biochar formation, but these effects are challenging to observe in biochars formed from whole biomass. When the model bioenergy feedstock Populus trichocarpa (cottonwood), with predictable lignin macromolecular structure tied to genetic variation, is used as feedstock for biochar production, these effects become visible. In this work, two P. trichocarpa variants having lignin S/G of 1.67 and 3.88 were ground and pyrolyzed at 700 °C. Water-demineralization of feedstock was used to simultaneously evaluate any synergistic influences of S/G and naturally-occurring potassium on biochar physicochemical properties and performance. The strongest effects of lignin S/G were observed on specific surface area (S) and oxygen-content, with S/G of 1.67 improving S by 11% and S/G of 3.88 increasing total oxygen content in demineralized biochars. Functional performance was evaluated by breakthrough testing in 1% NH. Breakthrough times for biochars were nearly double that of a highly microporous activated carbon reference material, and biochar with S/G of 3.88 had 10% longer breakthrough time than its lower S/G corollary. Results support a combination of pore structure and oxygen-functionalities in controlling ammonia breakthrough for biochar.
木质素愈创木基/紫丁香基比值（S/G）长期以来一直被怀疑对生物炭的形成有可衡量的影响，但这些影响在由全生物质形成的生物炭中很难观察到。当用作生物炭生产原料的模式生物能源原料杨属树种（棉白杨）具有与遗传变异相关的可预测的木质素大分子结构时，这些影响就变得显而易见。在这项工作中，两种木质素 S/G 为 1.67 和 3.88 的杨属树种变体被粉碎并在 700°C 下热解。通过水脱矿化处理原料，同时评估 S/G 和天然存在的钾对生物炭物理化学性质和性能的协同影响。木质素 S/G 对比表面积（S）和含氧量的影响最大，S/G 为 1.67 的 S 提高了 11%，S/G 为 3.88 的生物炭中总含氧量增加。通过在 1% NH 中的突破测试评估功能性能。生物炭的突破时间几乎是高比表面积微孔活性炭参考材料的两倍，S/G 为 3.88 的生物炭的突破时间比其低 S/G 对应物长 10%。结果支持孔隙结构和氧官能团的组合控制生物炭中氨的突破。
