Study on the Effect of Dissolved Organic Matter of Carex tristachya on Soil Adsorption of Cu2+
Using Carex tristachya as the research object,the spectral characteristics of dissolved organic matter(DOM)in moss were analyzed using infrared spectroscopy,ultraviolet absorption spectroscopy,and three-dimensional fluorescence spectroscopy.The effect of DOM of Carex tristachya on soil adsorption of Cu2+was studied through isothermal adsorption equilibrium experiments and adsorption kinetics experiments,and the changes in composition before and after the reaction between DOM of Carex tristachya and Cu2+were analyzed.Research showed that the DOM of Carex tristachya had functional groups such as hydroxyl,carboxyl,carbonyl,and methyl,and was composed of four components:fulvic acid,fulvic acid like,humic acid like,and tryptophan like,with humic acid with relatively high molecular weight being the main component.Added DOM of Carex tristachya could reduce the maximum adsorption capacity,adsorption equilibrium rate,and adsorption affinity of Cu2+in the soil.The ultraviolet region like fulvic acid and humic acid like substances in the DOM of Carex tristachya could form a complex with Cu2+through functional groups such as carboxyl and hydroxyl groups.After the reaction,the number of unsaturated conjugated double bond structures,humification level,and the content of carbonyl,carboxyl,hydroxyl,and ester in the substituents on the aromatic ring of DOM of Carex tristachya significantly decreased.The research results provide basic data for the composition and structure of DOM of Carex tristachya,and provide scientific basis for resolving disputes over the impact of DOM on heavy metal activity.
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