The solvent extraction performance of N,N’-dimethyl-N,N’-dibutylmalonamide towa...

• Autor(es): Paiva, A. P. ; Carvalho, G. I. ; Costa, M. Clara ; Costa, Ana M. Rosa da ; Nogueira, C. A.
• Data: 2014
• Identificador Persistente: http://hdl.handle.net/10400.9/2477
• Origem: Repositório do LNEG
• Assunto(s): Platinum; Palladium; Malonamide derivatives; Solvent extraction; Hydrochloric Acid
• Tipo de Documento: Artigo
• Idioma: Inglês

Descrição

The solvent extraction performance of N,N’-dimethyl-N,N’-dibutylmalonamide (DMDBMA) in 1,2-dichloroethane (1,2-DCE) towards platinum(IV) and palladium(II) in hydrochloric acid media was systematically evaluated. Pt(IV) extraction (%E) increases with the HCl concentration in the aqueous phases, being always higher than 72%, whereas Pd(II) extraction decreases from 65% at 1 M HCl to 22% at 8 M HCl. Several stripping agents for the two metals were tested: Pt(IV) is successfully recovered by a 1 M sodium thiosulfate solution, whereas the best result for Pd(II) was achieved with 0.1Mthiourea in 1MHCl. The loading capacity of DMDBMA for Pt(IV) is high, and data obtained from successive extraction-stripping cycles suggest a good DMDBMA stability pattern. Attempts to replace 1,2-DCE by more environmentally-friendly diluents showed, in general, worse %E for Pt(IV). The dependence of Pt(IV) distribution coefficients on DMDBMA and chloride ion concentrations, as well as on acidity, are the basis of a proposal for the composition of Pt(IV) extracted species.