热解温度对花生壳生物炭产率及部分理化特性的影响

摘要

To study the characteristics of peanut-shell-biochar,evaluate its application value and po tential in agricultural and environmental field,this study carbonized peanut shell under different temperatures,300℃,500℃,700℃,respectively,and then measured the basic physical and chemical properties,in order to explore the characteristics and changing rule of peanut-shell-biochar with the pyrolysis temperatures.In this paper,peanut shell was put into the muffle furnace and carbonized for 2h with low-oxygen under different temperatures.The temperature was increased at a rate of 20 ℃/min,and then its physico-chemical properties were deternined.The results show that,with the increase of pyrolysis temperature,biochar production rate and CEC gradually decreased;Mineral macroelements content increased with the increase of pyrolysis temperature,particularly in the process of 500℃ ～700℃;Among the micromineral elements,element B had no obvious change rule and the other elements increased with the rise of pyrolysis temperature;With the temperature increasing,the number of alkaline functional groups on the surface of peanut-shell-biochar showed an increasing trend,while that of the acidic functional groups decreased;Peanut-shell-biochar pH changed from acidic to alkaline,and had a higher degree of aromatization,which enhanced its stability;Peanut-shell-biochar porosity under the condition of high temperature (700℃) was comparatively developed,micropores and mesopores were more abundant at higher temperatures,and the proportion of micropores was larger.%为了研究花生壳生物炭的特征,评价其农业与环境领域应用价值与潜力,该研究分别在300,500,700℃下制备花生壳生物炭,测定其基础理化性质,以期了解花生壳生物炭特征及其随热解温度的变化规律.将花生壳原料放入马弗炉中,达到目标温度后低氧炭化2h,然后对处理后样品进行理化性质的检测.结果表明,随着热解温度的升高,生物炭产率逐渐下降,土壤阳离子交换量(CEC)含量降低;大量矿质元素随着热解温度的升高含量增加,在500 ～ 700℃过程中,增幅较大;微量矿质元素中,B元素无明显变化规律,其他元素均随着热解温度的升高而增加;随热解温度的升高,花生壳生物炭表面的碱性官能团数量增加,酸性官能团的数量降低,花生壳生物炭的pH值由酸性变成强碱性,花生壳生物炭芳香化程度升高,稳定性增强;花生壳生物炭的孔隙度在高温(700℃)条件下比较发达,微孔和中孔均在较高温度下比较丰富,且微孔比重高于中孔.