畜粪蚯蚓处理后DOM变化及其与Cu(Ⅱ)的配合特性

Variation of fluorescence spectrum of DOM and the behavior change of DOM complexed with Cu(Ⅱ) before and after vermicomposting of livestock excrement

研究了畜粪、木屑混合物经蚯蚓处理后水溶性有机物(DOM)分子量及荧光光谱变化.结果表明,经蚯蚓处理后畜粪、木屑混合物中DOM分子量呈整体降低趋势,分子量分布范围变宽,但其DOM分子量仍高于无蚯蚓处理;蚯蚓处理后混合物DOM中的富里酸含量及分子结构芳香化程度增加明显.进一步就蚯蚓处理前后DOM与Cu(Ⅱ)配合后的荧光光谱分析表明,蚯蚓处理后DOM更易与Cu(Ⅱ)产生配合反应并导致其直链变短或芳香基团的裂解;DOM中与Cu(Ⅱ)配合的基团主要包括—OH和—NH2等;且蚯蚓处理后DOM中的富里酸类物质更易与Cu(Ⅱ)发生配合反应.

Livestock excrement amended with sawdusts was vermicomposted and investigated for alterations of molecular weight and fluorescence spectrum of dissolved organic matter（DOM） before and after vermicomposting.The results demonstrated after earthworm treatment,the molecular weight of DOM decreased in general,and its distribution range became larger while its molecular weight was still higher than the treatment without earthworm.The content as well as the scale of molecular structure aromatization of fulvic acid in DOM after vermicomposting was significantly increased.The analysis of fluorescence spectrum in terms of DOM complexed with Cu（Ⅱ）further revealed the effect that fluorescence quenching of Cu（Ⅱ） on DOM was remarkable,and DOM from vermicompost was more likely to complex with Cu（Ⅱ） and could lead to a shortening of its straight chain or the pyrolysis of aromatic group.Groups such as-OH and-NH2 in DOM engaged in the complexation with Cu（Ⅱ）.Moreover,fulvic acid in DOM after vermicomposting was more conducive to the complexation with Cu（Ⅱ）.