I&EC 146 |
| Kenji Takeshita and Misako Kondo. Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan |
| The synergistic extraction of Au(III) with an acidic extractant D2EHPA and an aqueous nitrogen-donor ligand TPEN was studied. Generally Au(III) is little extracted by acidic extractants, because of the formation of anionic complex in the aqueous solution. However, the extractability of Au(III) was improved largely by the addition of TPEN. A gold ion was complexed with a TPEN molecule in the aqueous solution and the formation constant of Au(TPEN)3+ was evaluated as about 1010 by potentiometric titration technique. The extraction of Au with D2EHPA may be promoted by the formation of cationic complex, Au(TPEN)3+. From these results, both the stoichiometric relation for the extraction reaction and the extraction constant were determined as Au(TPEN)3+ + 3(HR)2=Au(TPEN)R3(HR)3+3H+ Kex=10-4.26 These results suggest that Au(III) as well as other soft metals, such as Cd, Ag and Pd, is extracted synergistically by TPEN and D2EHPA. |
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Industrial and Engineering Chemistry Posters
5:00 PM-7:00 PM, Tuesday, March 30, 2004 Anaheim Convention Center -- Hall A, Poster
Division of Industrial and Engineering Chemistry |