Data/hora: 23/09/2024 04:47:50

Biblioteca(s): 	Embrapa Unidades Centrais.	
Data corrente: 	27/03/2008	
Data da última atualização: 	28/06/2018	
Autoria: 	CASAGRANDE, J. C.; SOARES, M. R.; MOUTA, E. R.	
Afiliação: 	José Carlos Casagrande, Universidade Federal de São Carlos/Centro de Ciências Agrárias/Departamento de Recursos Naturais e Proteção Ambiental; Marcio Roberto Soares, Universidade Federal de São Carlos/Centro de Ciências Agrárias/Departamento de Recursos Naturais e Proteção Ambiental; Ernesto Rinaldi Mouta, Universidade Federal de São Carlos/Centro de Ciências Agrárias/Departamento de Recursos Naturais e Proteção Ambiental.	
Título: 	Zinc adsorption in highly weathered soils.	
Ano de publicação: 	2008	
Fonte/Imprenta: 	Pesquisa Agropecuária Brasileira, Brasília, DF, v. 43, n. 1, p. 131-139, jan. 2008	
Idioma: 	Inglês	
Notas: 	Título em português: Adsorção de zinco em solos altamente intemperizados.	
Conteúdo: 	The objective of this work was to assess the effects of pH and ionic strength upon zinc adsorption, in three highly weathered variable charge soils. Adsorption isotherms were elaborated from batch adsorption experiments, with increasing Zn concentrations (0?80 mg L-1), and adsorption envelopes were constructed through soil samples reactions with 0.01, 0.1 and 1 mol L-1 Ca(NO3)2 solutions containing 5 mg L-1 of Zn, with an increasing pH value from 3 to 8. Driving force of reaction was quantified by Gibbs free energy and separation factor. Isotherms were C-, H- and L-type and experimental results were fitted to nonlinear Langmuir model. Maximum adsorption ranged from 59?810 mg kg-1, and Zn affinity was greater in subsoil (0.13?0.81 L kg-1) than in the topsoil samples (0.01?0.34 L kg-1). Zinc adsorption was favorable and spontaneous, and showed sharply increase (20?90%) in the 4?6 pH range. No effect of ionic strength was observed at pH values below 5, because specific adsorption mechanisms predominated in the 3?5 pH range. Above pH 5, and in subsoil samples, Zn was adsorbed by electrostatic mechanisms, since ionic strength effect was observed. Despite depth and ionic strength effects, Zn adsorption depends mainly on the pH.	
Palavras-Chave: 	adsorption envelope; adsorption isotherm; elemento-traço; envelope de adsorção; força iônica; isoterma de adsorção; trace element.	
Thesagro: 	Ph.	
Thesaurus Nal: 	ionic strength.	
Categoria do assunto: 	--	
URL: 	http://ainfo.cnptia.embrapa.br/digital/bitstream/item/38160/1/43n01a17.pdf	
Registro original: 	Embrapa Unidades Centrais (AI-SEDE)	
Exemplares: 	AI-SEDE - (42040-1) - UPE - AP - PP - 630.72081 - P474 -  - DIS