不同温度下制备花生壳生物炭的结构性质差异

Difference characteristics of biochar derived from peanut shell under different temperatures

热解温度是影响生物炭结构性质的重要因素。在200~700℃温度范围内,以花生壳为生物质原材料制备生物炭,并对生物炭的理化性质及结构组成进行表征,以期了解花生壳生物炭特征及其随热解温度变化的规律。结果表明,生物炭的产率随着温度的升高而减少,灰分和pH随着温度升高而增加。生物炭的C含量随着温度升高而增加,H元素含量却随着温度升高而减少。H/C随着温度的增加而减少。红外光谱分析表明,随着温度的升高生物炭的烷基基团减少,芳香化程度逐渐升高。500℃制备生物炭的K_2Cr_2O_7和KMnO_4氧化碳损失量最低,分别为18.6%和1.70%。X射线衍射分析表明,随着温度的升高,生物炭中草酸钙矿物分解消失,碳酸钙矿物形成。

Pyrolysis temperature is one key factor affecting the properties of biochar.Peanut shells were collected as raw material and converted into biochar at a series of temperatures from 200 to 700℃.The characteristics of the biochar were also analyzed and compared in order to investigate the nature of the biochar and changes with pyrolysis temperature.The results showed that the yield of biochar decreased with increasing pyrolysis temperature, whereas the ash and pH increased.Moreover, the carbon content increased with increasing pyrolysis temperature but the hydrogen content and the H/C decreased.The alkyl groups gradually disappeared while more aromatization was shown by new aromatic compounds with increasing pyrolysis temperature, based on Fourier Transform Infrared Spectroscopy analysis.The carbon loss from biochar formed at 500℃ by K2Cr2O7 and KMnO4 oxidation, were 18.6% and 1.70%, respectively, which were less than for the biochar formed at other pyrolysis temperatures.With the increase of temperature, the calcium oxalate in biochar decomposed and disappeared, and calcite formed, based on X-ray diffraction analysis.