Synthesis and characterization of zirconium(IV) 4-amino, 3-hydroxy naphthalene sulfonate ion exchanger: Quantitative separation of mercury from numerous metal ions

Zirconium (IV) 4-amino, 3-hydroxy naphthalene sulfonate ion-exchanger has been synthesized by mixing equimolar solutions of zirconium oxychloride and ammonium hydroxide in molar ratio 1:1.66 to get a gelatinous material. To this were added varying amounts of 4-amino, 3-hydroxynaphthalene sulphonic acid (ANSA) with constant stiring in order to ensure a complete adsorption of organic molecules to the surface of the gel. The ion exchange material shows a dual character possessing both cation and anion exchange capacities. The former is attributed to the dissociation of strong sulphonic groups from ANSA and acidic sites of hydrous oxide gel, the later one is due to the formation of a positive charge on the nitrogen atom ; in addition, the material may have a sorption capacity. A preliminary investigation to characterize the material has been carried out which includes IR, TGA, DTA and X-ray diffraction. On the basis of distribution coefficients the separation of Hg⁺² from Zn²⁺, Al²⁺, Ni²⁺, Ce⁴⁺, Mg²⁺, Pb²⁺, Mn²⁺, Cu²⁺, has been achieved. The decreasing sequence of Kd values for different anionic species are found to be PO₄^3? > Fe (CN)₆^3? > MnO₄^? > VO₃^? > AsO₄^3? > C₂O₄^2? and for halides Cl^? > Br^? > I^?.