Data/hora: 14/06/2024 04:32:32

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