Structural study of humic acids during composting of activated sludge-green waste: elemental analysis, FTIR and 13C NMR.
The humic acids extracted from a compost of activated sludge at different stages of maturity were characterized by various chemical techniques. Elemental analysis showed the reduction of H, and the H/C and C/N ratios and an increase in the proportion of N and S. At the end of composting C% and O% presented the same values as initially, although they increased in the intermediate stage. Based on the ratios of FTIR absorbance it was shown that the end product was enriched in etherified and peptidic compounds absorbing at 1384, 1034 and 1544 cm(-1). The alkyl and other N-rich and oxidized recalcitrant structures compose the new humic polymers produced during composting. In principal components analysis, the first axis, PC1: 49.75% considers the variability between structures in decomposition from the other parameters that concern the stable new humic polymers formed after composting. PC2 (40.5%) shows a negative correlation between (aromatic carbon, FA level) and (aliphatic carbon, HA level) during composting.
Amir
Soumia
S
Equipe de Chimie Appliquée et Sciences de l'Environnement, Université Sultan Moulay Slimane, Beni Mellal, Morocco.
Jouraiphy
Abdelmajid
A
Meddich
Abdelilah
A
El Gharous
Mohamed
M
Winterton
Peter
P
Hafidi
Mohamed
M
D000473:Alkanes / Q000032:analysis; D006812:Humic Substances / Q000032:analysis*; D006841:Hydrocarbons, Aromatic / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D012722:Sewage / Q000032:analysis / Q000737:chemistry*; D012987:Soil; D017550:Spectroscopy, Fourier Transform Infrared
D000473:Alkanes; D006812:Humic Substances; D006841:Hydrocarbons, Aromatic; D012722:Sewage; D012987:Soil