Equilibrium, thermodynamic behaviour and kinetic analysis of the adsorption of lead (II) and chromium (VI) ions using moringa olifera seeds Medinat Osundiya, T.S. Oyewole, R.A. Olowu, A.O. Akinlabi, M.J. Alegbe, L.O. Osifeko, A.A. Adejare Department of Chemistry, Lagos State University, Ojo, Nigeria Adsorption is a surface phenomenon where particles are attached to the top layer of a material.The research focuses on the study of adsorption isotherms, equilibrium, thermodynamic behavior, and the kinetic analysis of the removal Pb (II) and Cr (VI) ions using Moringa oleifera biomass (MoB). The prepared MoB was characterized using scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX), and Fourier transform infrared spectroscopy (FTIR) while the initial and equilibrium concentrations were determined using AAS. The results obtained at various concentrations using three different adsorption isotherms, the Langmuir, Freundlich, and Temkim, gave the maximum adsorption monolayer capacity (mg/g) of 87.45 for Pb (II), and 92.65 for Cr (VI). The optimum adsorption of 400 mg/L for Pb (II) and Cr (VI) were obtained at pH of 5 and 3 respectively with adsorbent dosage of 0.4 g, contact time of 120 min, and temperature of 330 K for both ions. The results further showed that Pb (II) and Cr (VI) ion uptake followed the pseudo-second-order rate expression. The values of the thermodynamic parameters ΔG, ΔH and ΔS were -7.450 kJ/mol, 6.613 kJ/mol and, 19.372 Jmol -1 K - 1 respectively. Overall the adsorption process was feasible, spontaneous, and endothermic, hence, moringa seeds were found to be promising adsorbent for the removal of Pb (II) and Cr (VI) from aqueous solutions at the temperature, dosage and pH studied
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