REMOVAL OF COPPER IONS FROM AQUEOUS SOLUTIONS BY USING RESINS FROM Pinus Radiate BARK RESINS

A large amount of copper ions are released into the environment, which significantly affects water resources. The reduction of copper contaminants and the potential reutilization of these ions are important issues for environmental and human health. Resin based on Pinus radiata tannin and its derivatives obtained via chemical modifications with three cyclic anhydrides (maleic, citraconic, and itaconic) adsorbed Cu(II) from aqueous solutions. It was carried out in order to incorporate functional groups able to interact with heavy metal ions. The effect of the pH on the adsorption, desorption, and maximum adsorption capacity for Cu(II) solutions was studied. The adsorption depends largely on the pH of the solution, and the highest adsorption was observed at pH 3. Modified tannins showed lower maximum adsorption values than the original tannin. However, tannins modified with maleic and citraconic anhydrides presented larger values than the unmodified tannin under high ion concentrations. The resin showed an adsorption capacity of Cu (II) of approximately 55 mmol g-1 and a desorption capacity higher than 55%. It is the reason why it represents a complementary alternative, with respect to current treatments, for future use in the treatment of contaminated water.