Selective uptake and recovery of palladium by biopolymer microcapsules enclosing Cyanex 302 extractant

Selective uptake and recovery of platinum group metals are an important sub ject in the high level liquid waste treatment. An extractant having a stron g affinity for palladium, bis(2,4,4-trimethylpentyl) monothiophosphinic aci d (Cyanex 302, HA), was enclosed into microcapsules by utilizing highly imm obilizing ability of biopolymer (alginate and alginic acid gel polymers). T he uptake of Pd2+, Ru(NO)(3+) and Rh3+ for granular microcapsules has been studied by batch and column methods. A relatively large distribution coeffi cient of P2+, K-d.Pd, of above 10(4) cm(3)/g was obtained in the presence o f 0.2-0.5 M HNO3 and the separation factors of Pd/Ru and Pd/Rh were estimat ed to he above 10(2). The uptake of Pd2+ on microcapsules followed a Langmu ir-type uptake isotherm and the maximum uptake capacity was estimated to be 0.72-0.96 mmol/g. These metal cations M ere chromatographically separated through the column packed with HA-alginate microcapsules.