Data/hora: 09/06/2024 08:32:48

Provedor de dados: 	Pesquisa Agropecuária Brasileira	
País: 	Brazil	
Título: 	Zinc adsorption in highly weathered soils	
Autores: 	Casagrande,José Carlos; Soares,Marcio Roberto; Mouta,Ernesto Rinaldi.	
Data: 	2008-01-01	
Ano: 	2008	
Palavras-chave: 	PH; Adsorption envelope; Adsorption isotherm; Ionic strength; Trace element.	
Resumo: 	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.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2008000100017	
Editor: 	Embrapa Secretaria de Pesquisa e Desenvolvimento

Pesquisa Agropecuária Brasileira	
Relação: 	10.1590/S0100-204X2008000100017	
Formato: 	text/html	
Fonte: 	Pesquisa Agropecuária Brasileira  v.43 n.1 2008	
Fonte: 	info:eu-repo/semantics/openAccess