|
|
|
| Spectrum analysis on the evolution of dissolved organic matter during cattle manure composting |
|
|
|
|
Abstract 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 ~ 3.1δ decreased from 43.06% to 8.63%, 3.1 ~ 5.5δ increased 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 aromaticitychains were oxidized, and the molecular weight of DOM increased, which increased the humification degree and stability of composts.
|
|
Received: 31 December 2013
|
|
|
|
|
|
|
