Structural features of humic acids isolated from soils amended with urban organic residues: an elemental composition, 13C NMR and Py-GC/MS analysis

Revista Brasileira de Ciência do Solo

L. P. Canellas²  A. A. Moraes¹  V. M. Rumjanek¹  M. R. Garcia¹  F. Guridi¹  G. A. Santos¹  A. C. X. Velloso¹  R. Braz-filho¹ 

[1] ,Universidade Estadual Norte Fluminense Soil Laboratory Agricultural Science and Technology CenterCampos dos Goytacazes RJ

关键词: humic substances;    soil quality;    spectroscopic methods;    urban compost;    sewage sludge;    substâncias húmicas;    qualidade do solo;    métodos espectroscópicos;    composto de lixo;    lodo de esgoto;   

DOI  :  10.1590/S0100-06832002000200006

来源: SciELO

【 摘 要 】

The structural features of humic acids (HA) after addition of organic matter from urban residues were evaluated. The HAs were extracted from the surface (0-20 cm) of an ultisol (Seropédica, RJ) and oxisol (Piraí, RJ) which had been treated with the equivalent of 80 t ha-1 (dry material) of compost from urban waste and also sewage sludge. The incubation time in the laboratory was 24 weeks under room temperature and humidity at field capacity. Tha HAs were characterized by elemental analysis, 13C NMR spectroscopy and pyrolysis coupled to gas chromatography/mass spectrometry (Py-GC/MS). NMR spectroscopy allowed the clear observation of alterations in the molecular composition of the HAs, mainly through the increase in the content of mono and dioxygenated carbon atoms (δ 50-100) and decrease in the content of CH2 and CH3 groups (δ 0-40). The increase in the amount of carbohydrates suggests the presence of more labile structures in the HAs with organic residues amendment. In addition, Py-GC/MS led to the observation of significant qualitative differences between the compounds which arose from the thermal fragmentation of HAs, mainly lipids and carbohydrate derivatives (such as furan), for soil samples treated with either organic residues. The coupling of 13C NMR spectroscopy and Py-GC/MS has proven useful in evaluating physical changes in HAs isolated from soils treated with urban organic residues.

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License