Kinetic and equilibrium studies of Pb(II) and Cd(II) adsorption on African wild mango (Irvingia gabonensis) shell

Abstract

ABSTRACT. The adsorption behavior of NaOH-activated African wild mango (Irvingia gabonensis) shell with respect to Pb 2+ and Cd 2+ has been studied in order to consider its application to purify metal finishing waste water. The optimum conditions of adsorption were determined by investigating the initial metal ions concentration, contact time, adsorbent dose, pH value of aqueous solution and temperature. The extent of adsorption of metal ions was investigated by batch method using metal concentrations in solution ranging from 5-200 mg/L. The adsorption efficiencies were found to be pH dependent, with maximum metals uptake recorded at pH of 5. The equilibrium adsorption capacity for lead and cadmium ions were obtained from Freundlich, Langmuir, Temkin and DRK isotherms and the experimental data were found to fit best the Langmuir isotherm with values of 21.28 and 40.00 mg/g for Cd(II) and Pb(II) ions, respectively. The Pseudo-second order kinetics model had the best fitting for lead and cadmium adsorption kinetic data. The thermodynamic investigation showed that the adsorption processes of both metals are exothermic. An optimum concentration of 0.05 M HCl was found to be adequate for the regeneration of the spent adsorbent with recovery values of 78% and 71% for Pb 2+ and Cd 2+ respectively from the spent adsorbent. The results revealed that lead and cadmium are considerably adsorbed on the adsorbent and could be an economic method for the removal of these metals from aqueous solutions.

Trends in Adsorption Mechanisms of Fruit Peel Adsorbents to Remove Wastewater Pollutants (Cu (II), Cd (II) and Pb (II))

“…By increased 10°C − 20°C of the temperature process cannot directly affect the adsorption kinetic [71]. It has been proven that the removal efficiency of Pb (II) ions decreased with temperature due to the tendency of Pb (II) ions to escape from the liquid to the bulk phase [100]. Moreover, it weakened the electrostatic interaction, which is involved in the ion binding.…”

Correlation of Activated Carbonized Avocado Pear Seeds (Persea Americana) and Activated Carbonized Orange Peels (Citrus Sinensis) Adsorptive Potency in Eliminating Cd2+ Ions in contaminated water

“…E = 1/(-2β) 1/2 (5b) (Adekola et al, 2016, Ghasemi et al, 2018 q D (mol/g) signifies all-out adsorption capacity, β is the constant of Dubinin-Radushkevich isotherm (mol 2 /kJ 2 ), it denotes adsorbate free energy per mole as the aforementioned rove to the surface of the adsorbent from inestimable distance. E is adsorption mean free energy (kJ/mol), if E is less than 8, the adsorption means is governed by physisorption route, whilst if E is greater than or equal to 8 or E is less than or equal to 16, then adsorption route is governed via chemisorption (ion-exchange route) route and if E is greater than 16, the adsorption means is governed via diffusion of particle.…”