Data/hora: 23/06/2024 20:27:35

Biblioteca(s): 	Embrapa Solos.	
Data corrente: 	12/08/2014	
Data da última atualização: 	08/11/2021	
Autoria: 	ARAÚJO, J. R.; ARCHANJO, B. S.; SOUZA, K. R. de; kwapinski, w.; FALCÃO, N. P. S.; NOVOTNY, E. H.; ACHETE, C. A.	
Afiliação: 	Joyce R. Araujo, Instituto Nacional de Metrologia, Qualidade e Tecnologia; Braulio S. Archanjo, Instituto Nacional de Metrologia, Qualidade e Tecnologia; Katia R. de Souza, Instituto Nacional de Metrologia, Qualidade e Tecnologia; Witold Kwapinski, Department of Chemical and Environmental Science, University of Limerick; Newton P. S. Falcão, Departamento de Ciências Agronômicas, Instituto Nacional de Pesquisas da Amazônia, Manaus.; ETELVINO HENRIQUE NOVOTNY, CNPS; Carlos A. Achete, Universidade Federal do Rio de Janeiro.	
Título: 	Selective extraction of humic acids from an anthropogenic Amazonian dark earth and from a chemically oxidized charcoal.	
Ano de publicação: 	2014	
Fonte/Imprenta: 	Biology and Fertility of Soils, v. 50, n. 8, p. 1223-1232, 2014.	
DOI: 	https://doi.org/10.1007/s00374-014-0940-9	
Idioma: 	Inglês	
Conteúdo: 	Spectroscopic techniques including X-ray photoelectron spectroscopy (XPS) can identify particular chemical groups of humic acids (HA) from "Terra Preta de Índios" (TPI) or Amazonian dark earth, the highly fertile anthropogenic soil found in the Amazonian region. The high fertility and resilience of these soils cannot be explained by their chemically inert pyrogenic C content alone, but the natural aging of this C generates reactive carboxyl functional groups attached directly to the recalcitrant polycondensed aromatic backbone. Through spectroscopic techniques used in this work, the HA fraction (the alkaline-soluble organic matter that precipitates at low pH) of the TPI soil was compared with humic and fulvic acids, obtained by oxidizing activated charcoal with sodium hypochlorite. The yields recovery of HAlike substances was 12 and 28 wt% by using 10 and 20 cmol L-1 of oxidizing agent, respectively. X-ray photoelectron spectroscopy, energy dispersive X-ray, and solid-state 13C nuclear magnetic resonance (13C NMR) spectroscop Spectroscopic techniques including X-ray photoelectron spectroscopy (XPS) can identify particular chemical groups of humic acids (HA) from "Terra Preta de Índios" (TPI) or Amazonian dark earth, the highly fertile anthropogenic soil found in the Amazonian region. The high fertility and resilience of these soils cannot be explained by their chemically inert pyrogenic C content alone, but the natural aging of this C generates reactive carboxyl functional groupsattached directly to the recalcitrant polycondensed aromatic backbone. Through spectroscopic techniques used in this work, the HA fraction (the alkaline-soluble organic matter that precipitates at low pH) of the TPI soil was compared with humic and fulvic acids, obtained by oxidizing activated charcoal with sodium hypochlorite. The yields recovery of HAlike substances was 12 and 28 wt% by using 10 and 20 cmol L-1 of oxidizing agent, respectively. X-ray photoelectron spectroscopy, energy dispersive X-ray, and solid-state 13C nuclear magnetic resonance (13C NMR) spectroscopies were used to evaluate the elements and structures present in all samples. XPS C 1 s spectra of HA extracted from TPI soil and from prepared HA showed aromatic structures (C=C and * shake-up satellite peak) bounded to carboxyl groups (COOH). The morphology and polycondensation level of aromatic C were evaluated by scanning electron microscopy (SEM). The similarities of the spectra indicated that the used method was efficient to obtain an organic amendment similar to TPI soil organic matter.	
Palavras-Chave: 	Ácido húmico; Amazon dark earth; Humic acid.	
Thesaurus Nal: 	terra preta.	
Categoria do assunto: 	P Recursos Naturais, Ciências Ambientais e da Terra	
Registro original: 	Embrapa Solos (CNPS)	
Exemplares: 	CNPS - (18393-1) - UPC - AP - DD -  -  - 2014.00535 - DIS