Utilisation of sea nodules leaching residue for adsorption of Ni(II) ions

Polymetallic sea nodules may be considered as lean grade ore of Cu, Ni & Co. After recovery of these valuable metals, a huge quantity of residue (~70% of ore body) is generated. In the present paper, investigations carried out for the application of leached sea nodule residue for the removal of Ni(II) from aqueous solution by adsorption, are described. Several parameters have been varied to study the feasibility of using residue as potential adsorbent for remediation Ni(II) contaminated water. The adsorption kinetics followed pseudo first-order equation and the rate of adsorption increased with solution temperature. Kinetics data of Ni(II) adsorption was also discussed using diffusion models of Webber-Morris and Dumwald-Wagner models. The equilibrium data was best fitted into Langmuir adsorption isotherm and the maximum adsorption capacities was found to be 15.15 mg g-1 at pH 5.5 and temperature 303 K, which decreased to 10.64 mg g-1 upon raising the solution temperature to 323 K. The activation energy for Ni(II) adsorption onto leached sea nodule residue was 9.56 kJ mol−1 indicated physical sorption. Desorption studies showed successful regeneration of adsorbent and recovery of Ni. This process can be utilised for removal and recovery of Ni from the industrial effluent.