快速和慢速热解对棉秆生物炭理化特性及土壤持水量的影响

Characterization of Cotton Stalk Biochar Using Fast and Slow Pyrolysis and Its Effect on Soil Water Holding Capacity

以新疆棉秆为原料,在300~700℃下利用快速和慢速热解方式制备了生物炭,研究了快速和慢速热解对棉秆生物炭形貌、表面官能团、pH值、元素组成的影响.利用室内土柱试验,研究了不同条件下制备的生物炭对土壤持水量的影响.结果表明:1)随着热解温度的升高,生物炭产率下降,pH值提高,孔隙度增加.快速热解生物炭具有孔隙发达、芳香性高、稳定性强的优点.2)土壤持水量随着生物炭添加量和热解温度的升高而提高.生物炭添加量为0.03 g/g时,土壤持水量分别为51.7%和49.7%,比未添加生物炭提高了32.5%和27.4%.3)添加生物炭土壤15 d后保水量仍有40.3%,远高于纯土壤,且添加快速热解生物炭的土壤保水量高于慢速热解生物炭.

Biochar was prepared by fast and slow pyrolysis methods using Xinjiang cotton stalk as biomass at the pyrolysis temperature of 300~700℃.The effects of fast and slow pyrolysis methods on the morphology,structure,functional groups,pH value,and elemental composition of biochar have been studied.The effect of biochar prepared under different conditions on soil moisture capacity was studied using indoor soil column experiments.The results showed that:1)The biochar yield decreased,the pH value and the porosity increased with increasing pyrolysis temperature.Fast pyrolysis biochar has the advantages of well-developed pores,high aromaticity,and strong stability.2)The soil water holding capacity increases with the increase of biochar addition and pyrolysis temperature.When the amount of biochar addition was 0.03 g/g,the soil water holding capacity was 51.7% and 49.7%,respectively,which was 32.5% and 27.4% higher than that without biochar.3)The water retention of soil with biochar addition is much higher than that of pure soil.The soil added with biochar still retains 40.3% water retention after 15 days.The soil water retention of biochar added soil prepared by fast pyrolysis is higher than that of slow pyrolysis.