牛粪堆肥过程中水溶性有机物演化的光谱学研究

摘要

采用紫外-可见吸收光谱、1H-核磁共振(NMR)和同步荧光光谱,研究了牛粪堆肥水溶性有机物(DOM)的结构特征及其演化规律.紫外-可见吸收光谱分析显示,SUVA254由堆肥起始的1.161上升至堆肥结束的2.543；E465/E665在整个堆肥过程中呈现上升趋势,变化范围在2.333~3.500；260~280,460~480,600~700nm 范围内的面积积分 A1、A2和 A3均呈现出先增大后减小的趋势,峰值分别出现在26,14,14d.1H-NMR分析显示,堆肥0d到堆肥41d,0.5~3.1δ面积积分所占比例从43.06%下降至8.63%,3.1~5.5δ从56.07%上升至89.68%,5.5~10δ不足总体的6%且变化趋势不明显.同步荧光光谱结果显示,经过41d 的堆肥,蛋白质类物质区积分面积比例(APLR)由0.331下降到0.252,而富里酸类物质区积分面积比例(AFLR)由0.325增加到0.336,同时胡敏酸类物质区积分面积比例(AHLR)由0.344增加到0.412；AFLR/APLR比与同步荧光光谱3个荧光峰峰高存在显著相关性,AHLR/AFLR与两个荧光峰光强的比值I351/I284和I382/I351存在显著相关性.上述结果表明,随着堆肥进行, DOM 中的非腐殖质物质转化为类腐殖质,同时其芳香性结构增多,碳链结构发生氧化反应,分子量从小变大,堆肥腐殖化程度加大,稳定度增加.%UV-visible spectra, 1H-nuclear magnetic resonance (NMR) and synchronous-scan fluorescence spectra were applied to investigate the structural characteristics and evolution of dissolved organic matter (DOM) from cattle manure during the process of composting. The result from UV-visible spectra showed that, SUVA254 increased from 1.1614 at the initial stage to 2.543 at the curing stage, E465/E665 exhibited an upward trend with a variation range of 2.333~3.500, and the integration area within the range of 260~280 (A1), 460~480 (A2) and 600~700 nm (A3) all increased first then decreased with the maximum values at 26,14 in 14d, respectively. The result from the 1H-NMR analysis showed that, percentage of the integration area within the range of 0.5~3.1δdecreased from 43.06%to 8.63%, 3.1~5.5δincreased from 56.07% to 89.68%, and 5.5~10δ was below 6% with a insignificant variation tendency during composting. The analysis from synchronous-scan fluorescence spectra showed that, the integrated area ratio of protein-like substances (APLR) decreased from 0.331 to 0.252, that of fulvic-like acid matter (AFLR) increased from 0.325 to 0.336, while that of humic-like acid matter (AHLR) increased from 0.344 to 0.412 at the same time. The AFLR/APLR ratio and the fluorescence intensities of three peaks from synchronous-scan spectra exhibited an obvious correlation. In addition, significant correlation also observed between AHLR/AFLR ratio and I351/I284 and I382/I351 ratios. of DOM increased, the carbon structure In conclusion non-humic substances were transformed into humic matter during cattle manure composting, the aromaticity chains were oxidized, and the molecular weight of DOM increased, which increased the humification degree and stability of composts.