低温密封法制备玉米秸秆不同部位生物炭及特性比较

针对玉米秸秆利用困难问题，探索玉米秸秆制备生物炭工艺及其理化性能，采用密封限氧法，以玉米秸秆皮、瓤、根为研究对象，分别在300 ℃/45 min、500 ℃/ 30 min、700 ℃/15 min条件下制备生物炭并分析其特性，包括炭产率、pH值、灰分含量、红外光谱和扫描电镜分析。结果表明：在300~700 ℃时，随温度升高，炭产率降低，热解失重速率先增后减，pH值均升高；相同条件下，生物炭特征吸收峰基本相同，表现为表面官能团总量减少，酸性官能团降低，碱性官能团增加。综合分析，秸秆根生物炭与秸秆瓤、秸秆皮生物炭材料功能性相近，研究结果可为玉米秸秆根部的资源化利用提供理论依据和技术支持。

Comparative Study on Properties of Biochar from Different Parts of Maize Straw Prepared by Low-temperature Sealing Method

To solve the difficulty with utilization of maize straw root， the technology of biochar preparation from maize straw root and the biochar properties are analyzed. First， biochar was prepared with the husk， flesh and root of maize straw separately at 300℃/45min， 500℃/30min and 700℃/15min through the sealed oxygen-limiting method. Then， the biochar properties were analyzed， including analyses of the char yield， pH， ash content， infrared spectroscopy， and scanning electron microscopy. The results showed that the carbon yield decreases with temperature， the loss rate of pyrolysis weight increases first and then decreases， and the pH value increases in the range from 300℃ to 700℃； in addition， the characteristic absorption peaks of biochar are basically the same， represented as the total surface functional groups decrease， the acidic functional groups decrease， and the basic functional groups increase. In a word， straw root biochar is similar in functionality to straw pith and straw bark biochar materials. Therefore， the results of this study can be used as theoretical basis and technical support for the resource utilization of maize straw.