老化作用对生物炭理化特性的影响

Effect of Aging on Physicochemical Properties of Biochars

以松木屑、玉米秸秆、小麦秸秆和花生壳四种生物质热解制备的生物炭为对象,分别采用自然老化、高温老化、冻融老化对四种生物炭进行5个月老化培养。结合元素分析、扫描电镜分析(SEM)、N_(2)吸附/脱附分析、X射线衍射分析(XRD)、傅里叶红外光谱分析(FTIR)和pH测定等表征分析,研究了老化方式对生物炭理化特性的影响。结果表明,老化过程能够显著提高生物炭的BET比表面积,改善生物炭的微观孔隙结构,降低C元素含量,增加O元素含量,提高H/C、O/C和(O+N)/C以及表面含氧官能团数量,并降低生物炭的pH值,老化方式对生物炭理化特性改善效果顺序为高温老化■冻融老化■自然老化。

Aging incubation experiments of natural aging,high temperature aging and freeze-thaw aging for 5 months were carried out by using four biochars prepared by pyrolysis of biomass involving pine chip,corn straw,wheat straw and peanut shell.The effects of aging method on the physiochemical properties of biochars were investigated based on the determination of ultimate analysis,scanning electron microscope(SEM),N_(2)adsorption/desorption analyzer,X-ray diffractometer(XRD),Fourier infrared spectrometer(FTIR)and pH measurement.The obtained results showed that the aging process can significantly lead to increasing BET specific surface area,improving micro-pore structure,decreasing C element content,increasing O element content and the molar ratios of H/C,O/C and(O+N)/C,and the development of surface oxygen-containing functional groups resulting in lower pH.The improvement effect of aging method on biochar physiochemical properties is ordered as high temperature aging>freeze-thaw aging>natural aging.