Data/hora: 09/06/2024 13:22:59

Provedor de dados: | 52
País: | Brazil
Título: | Nickel adsorption by variable charge soils: effect of pH and ionic strength
Autores: | Soares,Marcio Roberto; Casagrande,José Carlos; Mouta,Ernesto Rinaldi.
Data: | 2011-02-01
Ano: | 2011
Palavras-chave: | Adsorption isotherms; Free energy; Adsorption envelopes; Adsorption edges; Ionic strength.
Resumo: | The effects of pH and ionic strength (I) on Ni adsorption in variable charge soils were evaluated by laboratory batch experiments. Experimental results fitted the Langmuir model. Maximum adsorption (Ads max) ranged from 260-2818 mg kg-1 (topsoil) to 532-1541 mg kg-1 (subsoil). Nickel affinity (K L) was higher in the subsoil samples (0.022-0.236 L kg-1) than in topsoil (0.003-0.049 L kg-1). Adsorption envelopes showed sharp increase in Ni adsorption (20-90%) in the 4.0-6.0 pH range. Nickel adsorption was affected by I and specific adsorption predominated in the 3.0-5.0 pH range, while above pH 5.0, it was adsorbed by electrostatic mechanisms. Negative values of free energy variation (ΔG) and the separation factor K R&lt;1 indicated that Ni adsorption reaction was favorable and occurred spontaneously, especially when pH increase. Chemical and mineralogical soil attributes should be considered as criteria for selecting the areas for disposal of residues containing Ni to minimize the impact on the environment.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132011000100025
Editor: | Instituto de Tecnologia do Paraná - Tecpar
Relação: | 10.1590/S1516-89132011000100025
Formato: | text/html
Fonte: | Brazilian Archives of Biology and Technology  v.54 n.1 2011
Fonte: | info:eu-repo/semantics/openAccess