几种生物质热解炭基本理化性质比较

Comparison of biochars characteristics from biomass residues produced through slow pyrolysis

生物炭由生物质材料在无氧或缺氧条件下经高温裂解形成,是土壤改良和废弃物处理的良好改良剂。选取五种生物质原料(大豆秸秆、玉米秸秆、水稻秸秆、稻壳和松针,均为农林废弃物),经300、400、500、600和700℃热解2 h,测定其结构及理化性质。研究结果表明,生物炭炭化结构良好清晰;生物质形成生物炭在BET比表面积、T-PLOT微孔容积、p H和阳离子交换量值方面均随热解温度升高而升高,大豆秸秆和玉米秸秆比表面积在700℃时达到最高;平均孔径随热解温度升高有一定程度下降;700℃下水稻秸秆和稻壳形成生物炭具有最高硅含量。除松针炭外,其余各生物炭呈碱性。

Biochar has been well considered to be a good modifying agent in soil remediation and waste disposal. The characteristics of biochars are significantly influenced by the heating temperature and different biomass. Corn stalk, rice straw, rice husk, soybean straw and pine needle were pyrolysed at 300, 400, 500, 600 and 700 ℃, respectively. The structures and phychemcial characteristics of biochars produced from the different feedstocks were compared. Results showed that the BET surface area, T-Plot micropore volume, p H, alkaline functional groups and cation exchange capacity of biochars increased with the rising of the pyrolysis temperature. However, the average pore diameter of biochars decreased with the pyrolysis temperature increased. The surface areas of biochar derived from corn stalk was the highest at 700 ℃. Biochar derived from rice husk and rice straw had the highest Si content. Biochar derived from corn stalk, rice straw, rice husk, soybean straw showed alkaline, expect for pine needle biochar.