堆肥过程水溶性有机物组成和结构演化研究

基于Leenheer的分组方法,用XAD-8树脂将鸡粪不同堆肥阶段样品提取出的水溶性有机物(DOM)按极性和电荷特性分为疏水酸性组分(HOA)、疏水碱性组分(HOB)、疏水中性组分(HON)、酸不溶组分(AIM)及亲水性组分(HIM),采用元素分析、核磁共振(~1H-NMR)及红外光谱(FTIR),对各组分的组成和结构特征进行了研究.结果表明,堆肥DOM中HIM和HOA组分的含量分别为32%~44%和35%~47%,而HOB、AIM及HON组分之和不到25%,经堆肥后HIM组分含量下降,而疏水性组分含量增加.元素分析显示,堆肥过程N、C、S含量呈增加趋势,经堆肥后有机质H/C比降低,腐殖化率提高;~1H-NMR分析表明:HIM组分中烷基链烃的含量最少,支链最短,分支较多,碳水化合物含量高,而HON组分的组成恰好与之相反,AIM组分结构类似胡敏酸,HOB富含含氮化合物.FTIR分析表明,HOA和HOB组分富含羧基、酯基和醇羟基官能团,而AIM和HIM除上述官能团外,还含有大量苯环官能团,HON组分富含脂肪族官能团,该组分官能团种类最多,经堆肥后,脂族官能团含量降低,苯环官能团增加.

Composition and Evolution Characteristics of Dissolved Organic Matter During Composting Process

According to the fraction method presented by Leenheer, dissolved organic matter (DOM) extracted from chicken manure with different composting time was fractionated into five groups i. e., hydrophobic acid (HOA), hydrophobic base (HOB), hydrophobic neutral (HON) fractions, acid-insoluble (AIM) and hydrophilic matter (HIM)] using the XAD-8 resin based on its polarity and electric charge characteristics. The composition and structures of these fractions were investigated by elemental analysis, FTIR and ¹H-NMR spectra. The results showed that the HIM and HOA fractions accounted for 32%-44% and 35%-47% of DOM, respectively, during the composting process, while the sum of the fractions HOB, AIM and HON was responsible for less than 25% of DOM. The HIM content decreased while the hydrophobic component increased after composting. The elemental analysis indicated that, during the composting process, the N, C, S content of all five fractions increased, the H/C ratio decreased, but the humification degree increased; The result from ¹H-NMR analysis showed that the HIM had low alkyl chain, short branched chain, high branches and carbohydrate structure, which was opposed to the HON fraction. The composition of AIM was similar to that of humic acids, while the HOB was rich in nitrogen-containing compounds. The result from the FTIR analysis showed that the HOA and HOB fractions were rich in abundant carboxyl, ester group and hydroxyl functional group. Besides the above functional groups, the AIM and HIM were rich in benzene groups. The HON fraction was rich in aliphatic functional group except for the abovementioned functional groups. The aliphatic functional group was degraded and the benzene functional group after composting.