Abstract: A cellulosic cationic ion-exchange composition is formed by sulfonation of activated cellulose having of high surface area characteristics, using an acid such as concentrated H.sub.2 SO.sub.4. The sulfonated material is convertible into different forms, viz., H-form, Na-form, K-form, NH.sub.4.sup.+ form, Ba-form, Ca-form, and Cu-form by appropriate reaction. The cation-exchanger has been found useful to treat industrial effluents for the removal of heavy metals, to achieve recovery of precious metals, to carry out water-softening, and the like.