Abstract: A biomaterial adsorbent, locust bean seed coat powder (LBSCP) was prepared from locust bean seed coat for heavy metals removal from aqueous solutions. The LBSCP was characterized using XRF, for its elemental composition, FTIR, for functional groups, and SEM for surface morphology and the potential of LBSCP for the removal of Pb (II) and Ni (II) ions was investigated. The results obtained indicated that the locust bean seed coat powder (LBSCP) possessed excellent adsorption potential to adsorb the selected heavy metals (Pb (II) and Ni (II) ions). The LBSCP was activated using HCl, then the effect of dosage (1.0, 1.5, 2.0, 2.5, 3.0 g), time 15, 20, 25, 30, 35 min), temperature (288, 293, 303, 313, and 323 K) on the adsorption efficiency of the sample was tested using Pb (II) and Ni (II) ions solutions prepared from Pb(NO3)2 and Ni(NO3)2 salts. The result showed that removal efficiency (99.95%) was the most effective with Pb2+ ions when 1.0 g of MLBSCP was used. The result also showed that at 15 min of contact time more of Pb2+ ions (99.89 %) were removed by MLBSCP. The equilibrium adsorption data were tested with two different isotherms: Langmuir, and Freundlich. Best fitted was found to be Langmuir isotherm. The positive values of change in Gibb’s free energy (∆G) for the experiment range of temperatures showed that the adsorption process for the adsorption of pb2+ and Ni2+ is non-spontaneous. The positive values obtained for enthalpy change (ΔH) reveals endothermic nature of the adsorption process. The values obtained for change in entropy were negative suggesting that there was a decrease in the randomness between the adsorbent aqueous solutions interface during the adsorption process.

Key words: LBSCP, Kinetics, Isotherm, Adsorption, Thermodynamic, lead (II) ions, Nickel (II) ions.

Cite: Jeje, O. Ayorinde, Osula, J. E, Oregbeme Henry, "Isotherm, Kinetic and Thermodynamic Studies of Pb (II) and Nickel Ions Removal from Aqueous Solution Using Locally Sourced bio-Adsorbent," International Journal of Materials Science and Engineering, Vol. 7, No. 3, pp. 67-80, September 2019. doi: 10.17706/ijmse.10.17706/ijmse.2019.7.3.67-80