湿地植物生物炭衍生DOM与氯霉素的络合机制

Complexation of chloramphenicol and dissolved organic matter derived from the wetland plant biochar

了解生物炭溶解性有机质(BDOM)与污染物的络合机制对生物炭的应用具有重要意义.选取天然湿地植物灰化苔草为生物炭原料,利用荧光猝灭法及多种光谱分析技术和方法,分析了植物不同部位、不同热解温度下BDOM与氯霉素(CAP)的络合机制,以期为生物炭的生态修复提供理论支持.紫外-可见吸收光谱分析结果表明,BDOM与CAP的荧光猝灭属于静态猝灭,300℃制备的BDOM与CAP络合体系的芳香性化合物含量和分子量比500℃更大.同步荧光光谱分析结果发现类络氨酸和类色氨酸物质与CAP的络合能力更强.二维相关图谱分析结果表明植物根与叶的BDOM分别以类蛋白和类腐殖物质对CAP的猝灭更强,其中苔草根BDOM与CAP的猝灭优先发生于类蛋白物质中,但苔草叶BDOM以类腐殖物质为先.此外,通过三维荧光光谱结合平行因子分析法共解析出1个类蛋白荧光组分和5个类腐殖质荧光组分.总体来说,就单一组分而言,BDOM类蛋白组分与CAP的络合强度高于类腐殖质组分.

Understanding the complexation mechanism between biochar-derived dissolved organic matter(BDOM)and pollutants is of great significance for the application of biochar.In this study,a typical wetland plant Carex cinerascens was selected as the raw material of biochar.The complexation mechanism of BDOM from different plant organs(i.e.root and leaf)and chloramphenicol(CAP)at different pyrolysis temperatures was investigated by using the fluorescence quenching method,combined with several spectral analysis techniques and methods.The results of this study could provide theoretical data for the ecological restoration function of biochar.The results of UV-visible absorption spectrum analysis showed that the fluorescence quenching between BDOM and CAP was static quenching.The higher concentration of the aromatic substance and the larger molecular weight were observed in the complexation system of BDOM and CAP prepared at 300℃compared to 500℃,for both roots and leaves of the plant.The results of synchronous fluorescence spectrum analysis indicated that the complexing ability of the tyrosine-like and the tryptophan-like substances with CAP was stronger.Results of two-dimensional correlation spectroscopy revealed that the stronger complexation of BDOM from the roots and leaves with CAP was the protein-like substances and the humic-like substances,respectively.In addition,the fluorescence quenching effect occurred preferentially between the protein-like substances in BDOM of roots and CAP and between the humic-like substances in BDOM of leaves and CAP.Moreover,one protein-like component and five humic-like components were extracted,analyzed by using the three-dimensional fluorescence spectroscopy combined with parallel factor analysis.In terms of the single fluorescent component,a higher binding capacity was found for the protein-like components of BDOM with CAP than that of humic-like components.