Reactivity of inorganic anion exchanger BiPbO2(NO3) with fluoride ions in solution

In this study, we investigated the reactivity of BiPbO2(NO3) with aqueous fluoride ions. Although BiPbO2(NO3) is known to react very well with iodide or chloride ions in aqueous solution at and near pH 1 or 13, the reaction of BiPbO2(NO3) with fluoride ions has not been studied. The experimental result in the present study shows that fluoride ions reacted in solution at pH 1, but did not react at pH 6.5 or 13. The result at pH 13 differs from that of the other halide ions. It may be possible to use this difference to separate fluoride ions from other halide ions. Selectivity tests for F–I mixed solution and F–Cl mixed solution were carried out and gave the expected results. The reaction mechanism of BiPbO2(NO3) with fluoride ions at pH 1 was studied in solution where the NO3−1 was not exchanged with a fluoride ion; however, BiPbO2(NO3) decomposed producing bismuth oxide fluoride (β-phase).