几种原料生物炭溶解性有机质(DOM)的光谱特征研究

Spectral Characteristics of Dissolved Organic Matter Released from Biochar Made from Different Biomass

溶解性有机质(DOM)在全球碳循环及污染物的迁移转化过程中起着重要作用,而光谱特征能快速识别DOM的主要来源和重要特征。研究针对几种原料(苹果枝、橘子枝、花生壳、水稻秸秆、玉米秸秆)在同一热解温度下制备的生物炭,采用紫外-可见吸收光谱、三维荧光光谱和傅里叶变换红外光谱相结合的方法对其释放的DOM光谱特征进行了研究。结果表明:秸秆类生物炭的溶解性有机碳(DOC)含量显著高于其他3种生物炭;紫外-可见光谱分析表明,5种生物炭DOM的芳香性组分含量均较少,腐殖化程度较低,亲水性组分占主导;三维荧光光谱分析表明,秸秆类生物炭DOM的荧光组分物质含量高于木质类和壳类,且各荧光组分含量占比中可溶性微生物降解产物和类胡敏酸比例最高;傅里叶变化红外光谱表明,5种生物炭DOM光谱特征相似,含有丰富的有机官能团(如羧基、酚羟基等)或半醌自由基等。

The dissolved organic matter(DOM)has complex biogeochemical characteristics that affect the carbon cycle,migration and transformation of pollutants.The sources and the key properties of DOM can be identified quickly by the spectral characteristics.Therefore,the DOM spectrum characteristics of biochar made from five kinds of typical biomass(apple branch,orange branch,peanut shell,rice straw and corn straw)prepared at the same pyrolysis temperature were explored by using ultraviolet-visible spectrum,three-dimensional fluorescence spectrum and fourier transform infrared spectrum.The results show that the dissolved organic carbon(DOC)of straw biochar is much higher than that of the other three biochars.Ultraviolet-visible spectrum analysis shows that the content of aromatic components in DOM of the five biochars was small,the humification degree was low,and hydrophilic components were dominant.Three-dimensional fluorescence spectrum analysis shows that the content of fluorescent components of straw biochar DOM was higher than those of wood biochar and shell biochar,and soluble microbial degradation products and humic acid were the highest in the proportion of fluorescent components.Fourier transform infrared spectroscopy shows that the DOM spectral characteristics of the five biochar species were similar.