Selective Uptake and Recovery of Palladium by Biopolymer Microcapsules Enclosing Cyanex 302 Extractant

• Published in: Journal of nuclear science and technology Vol. 38; no. 5; p. 342
• Main Authors: MIMURA, Hitoshi, OHTA, Hiroshi, AKIBA, Kenichi, ONODERA, Yoshio
• Format: Journal Article
• Language: English
• Published: Tokyo Taylor & Francis Ltd 01.05.2001
• ISSN: 0022-3131; 1881-1248
• DOI: 10.3327/jnst.38.342

Selective uptake and recovery of platinum group metals are an important subject in the high level liquid waste treatment. An extractant having a strong affinity for palladium, bis(2,4,4-trimethylpentyl) monothiophosphinic acid (Cyanex 302, HA), was enclosed into microcapsules by utilizing highly immobilizing ability of biopolymer (alginate and alginic acid gel polymers). The uptake of Pd2+, Ru(NO)3+ and Rh3+ for granular microcapsules has been studied by batch and column methods. A relatively large distribution coefficient of Pd2+, Kd,Pd, of above 104 cm3/g was obtained in the presence of 0.2-0.5 M HNO3 and the separation factors of Pd/Ru and Pd/Rh were estimated to be above 102. The uptake of Pd2+ on microcapsules followed a Langmuir-type uptake isotherm and the maximum uptake capacity was estimated to be 0.72-0.96 mmol/g. These metal cations were chromatographically separated through the column packed with HA-alginate microcapsules.