A novel polyaniline-based composite cation-exchange material has been synthesized by a sol-gel method and characterized by standard analytical techniques such as thermogravimetry/differential thermal analysis, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, revealing the composite nature of the material with uniform surface morphology and the formation of particles of sizes ranging from 30 to 50 nm. The ion-exchange capacity of the composite synthesized at pH 1.0 was found to be 1.4 mequiv g(-1) for the Na+ ion along with thermal stability. Partition coefficient studies showed its selectivity for toxic metal ions (Pb-II, Hg-II and Co-II) among different metal ions in dimethyl sulfoxide solutions. Quantitative separations were quite sharp, and recovery was quantitative and reproducible from water samples by using columns of this exchanger. The conducting behavior and antimicrobial activity of the material was also investigated. The photocatalytic activity of the material showed 69% and 81% decolorization of AY29 and Rh B, respectively, after 300 min under UV irradiation.