炭化温度和时间对不同废菌棒生物炭结构性质的影响

Effect of Pyrolysis Temperature and Time on Structure of Biochar Made from Discarded Mushroom Stems

【目的】生物炭的表面性质与其表面的官能团密切相关,探讨不同制备条件对不同材料废菌棒生物炭结构特征的影响可为废菌棒的资源化有效利用提供依据。【方法】以海鲜菇、秀珍菇、银耳的废菌棒为生物质原料,采用限氧裂解法在不同温度(400、500、600、700℃)和不同时间(1.5、2.0、2.5、3.0 h)下制备生物炭,采用傅里叶红外光谱法(FTIR)对不同废菌棒生物炭结构性质进行表征。【结果】随着炭化温度的升高和炭化时间的延长,3种菌棒生物炭蛋白质中C=O、C-N、纤维素中C-O-C、脂肪烃中-CH3和-CH2基团的相对含量都随之减少;苯环中的C-H官能团相对含量随之减少,C-C官能团相对含量随之增大,且在700℃,炭化3.0 h条件下达到最大。在相同制备条件下,海鲜菇菌棒生物炭含氧官能团吸收峰峰强最强,银耳菌棒生物炭最弱;秀珍菇菌棒生物炭苯环CC吸收峰峰强最强,银耳菌棒生物炭最弱。【结论】随着炭化温度的升高和炭化时间的延长,生物炭中的蛋白质、多糖和脂肪酸等有机物质逐渐分解,烷基基团缺失,而芳香结构逐渐形成,在700℃,炭化3.0 h条件下生物炭结构最稳定。在3种菌棒生物炭中,海鲜菇菌棒生物炭对于重金属或有机污染物的吸附能力可能最强,秀珍菇菌棒生物炭施入土壤后固碳效果可能最好。

【Objective】 The surface property, which closely relates to the functionality, of biochar made from discarded mushroom stems under varied pyrolysis temperature and time was studied.【Method】 Waste of edible mushrooms including Hypsizygus marmoreus, Pleurotus geesteranus, and Tremella fuciformis was processed under oxygen-limited pyrolysis at 400℃, 500℃, 600℃ or 700℃ for 1.5 h, 2.0 h, 2.5 h or 3.0 h. The structure property of the resulting biochar samples was analyzed using Fourier transform infrared spectroscopy(FTIR).【 Result】 The increasing pyrolysis temperature and time reduced the relative contents of C=O and C-N in the proteins, C-O-C in the celluloses, and C-H functional groups in the benzene rings of the raw material, while raised the relative contents of C-C functional groups in the benzene rings reaching a maximum when processed at 700℃ for 3.0 h. Among the 3 biochar samples obtained under same pyrolysis conditions, the maximum absorption by the oxygen functional groups of H. marmoreus biochar was the highest, and that of T. fuciformis the lowest;whereas, that by the C-C functional groups in the benzene rings of P. geesteranus biochar was the highest, and T.fuciformis biochar the lowest.【Conclusion】 Increased pyrolysis temperature and time decomposed the organic substances such as proteins, polysaccharides, and fatty acids in the raw mushroom material, diminished the alkyls, and formed aromatics in the biochar. Processed under 700℃/3.0 h pyrolysis, the biochar attained a stable structure. As indicated by the analytical results, the H. marmoreus biochar was expected to be most effective among the 3 materials in removing heavy metals or organic pollutants, and the P. geesteranus biochar in carbon-sequestrating in soil.