Analytical Sciences

Extraction of Bismuth(III) with 2-Bromoalkanoic Acid in Nondonating Solvent from Highly Acidic Aqueous Solution

Yoshio MORIYA, Mikio SUGAI, Shin-ichi NAKATA, and Nobuaki OGAWA

Department of Materials-process Engineering and Applied Chemistry for Environments, Faculty of Engineering and Resource Science, Akita University, Tegata Gakuencho, Akita 010-8502, Japan

The extraction behaviors of bismuth(III) with carboxylic acid (HL), which have not yet been clearly elucidated, because of the precipitation of hydroxide, were studied using the 2-bromoalkanoic acid in benzene and in hexane systems under aqueous conditions of high acidity at I = 1.0 M ((H,Li)NO₃). The extraction equilibria were analyzed based on the initial concentration of nitric acid and the concentration of bismuth(III) extracted in the organic phase. The extracted species and the logarithmic values of the extraction constant (log K_ex) were found to be a single species of BiL₃(HL)₃ for the systems of 2-bromooctanoic acid/benzene (log K_ex = -1.66) and 2-bromohexadecanoic acid/benzene (-1.58), and to be two species of BiL₃(HL)₄ (-1.01) and Bi₃L₉HL (-1.62) for the system of 2-bromooctanoic acid/hexane, where the monomer was dominant at a higher reagent concentration.

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