1ADSORPTION OF METALS FROM METAL-ORGANIC COMPLEXES DERIVED FROM BIOLEACHING OF NICKEL LATERITE ORES

This study aims to establish the potential of an iminodiacetic-based chelating resin (Purolite S930) in recovering Ni and Co from the biological leachate. The adsorption tests were carried out to compare the hydrogen (H) and sodium (Na) forms of resin. The equilibrium adsorption isotherms were determined using metal citrate complexes with concentrations from 15 to 2000 mg/L. Adsorption tests were carried out for a period of 24 hours to attain adsorption equilibrium. The pH of the solution was varied using citric acid with concentrations of 0.01-1.0 M. The adsorption equilibrium data were interpreted using the Langmuir and Freundlich models. Metal elution was carried out using 2M HNO3 solution. The adsorption behaviors of nickel and cobalt citrate complexes were found to follow both Langmuir and Freundlich models. The results suggested that metal uptake were influenced by the hydrolysis of the resin and competition of metal complexes with the citrate anion and hydronium ion (H+). Metal elution was influenced by the interaction or reaction of metal complexes with the resin which included surface complexation