Effective and selective sorption of iodide by thin film of multilayered MnO(2) intercalated with cationic surfactants.

We have fabricated a thin film of multilayered MnO2 whose interlayer is occupied with hexadecylpyridinium (HDPy) cations, using a simple anodic approach. The resulting film can effectively sorb iodide anions from aqueous solutions, even in the presence of NaCl or Na2SO4. The maximum sorption capacity was estimated to be 256 mg/g-MnO2, whereas a layered MnO2 film intercalated with K(+) ions showed no significant sorption. The layered structure of the HDPy/MnO2 composite remained unchanged after a sorption experiment. This indicates the incorporation of I(-) ions between MnO2 layers due to their specific affinity toward HDPy.