Journal of Advanced Chemical Engineering

Abstract

Kinetic and Thermodynamics Studies of the Biosorption of Pb(II), Cd(II) and Zn(II) Ions from Aqueous Solution Using (Thaumatococcus danielli) Biomass

Adeniyi John Ademoyegun* and Adesola Babarinde

This study evaluated the kinetics, isotherms and thermodynamics of heavy metal ions sorption onto Thaumatococcus danielli (popularly known as the moimoi leaf). Different reaction conditions such as contact time, initial metal ion concentration and also temperature were investigated for the removal of Pb(II), Cd(II), Zn(II), ions from the aqueous solutions.

The batch biosorption study of the biomass onto metal ions revealed that the equilibrium time was reached at 150 mins for Cd(II) and Zn(II) and 180 mins for Pb(II) at optimum pH of 7. Contact time, initial metal ion concentration, biosorbent dosage and temperature are other reaction conditions which are found to influence the biosorption process.

The FT-IR study showed the presence of ionisable (-OH, C=C, C≡C, PH3 and C-H) functional groups which could participate in the binding of metal ions in solution.

The kinetic rates were modelled using the pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion. The experimental data fitted well to the pseudo-second-order kinetics with correlation R² values of 0.9935, 0.9963 and 0.9971 for Pb(II), Cd(II) and Zn(II) respectively. The experimental equilibrium biosorption isotherm were analysed with Langmuir, Freundlich, Temkin and Dubini-Radushkevich (D-R) isotherm models. The Freundlich isotherm model gave the best fit with the highest correlation coefficient R² with respective value of 0.9769, 0.8902 and 0.9717 for Pb(II), Cd(II) and Zn(II). The thermodynamics analyses indicate that the metal ions sorption on Thaumatococcus danielli is feasible, spontaneous and exothermic for both Pb(II) and Cd(II) but endothermic for Zn(II) ions.

These results indicate that Thaumatococcus danielli has potential for the uptake of Pb(II) and Cd(II) from polluted aqueous solution.

Published Date: 2024-09-13; Received Date: 2020-09-30