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In this study, kola-nut testa samples were modified with 0.1 M acetic acid and 0.1 M EDTA at room temperature. The modified Kola-nut testa samples were then characterized with respect to their pH at point of zero charge, melting point, specific gravity, Fourier-transform infrared (FTIR) spectra, and solubility. The characterization results of the modified Kola-nut testa (MKT) revealed that it was sparingly soluble in water, ethanol, and acetone but insoluble in n-hexane. The MKT had a specific gravity of 0.992 ± 0.020 and exhibited various pH values of 4.50 ± 0.50 and 12.00 ± 0.50 at the point of zero charges. The FTIR spectra of the MKT indicated the presence of –OH and –NH groups at 3310.97 cm−1, alkyl groups at 2928.53 cm−1, and aromatic rings at 1612.27–1529.81 cm−1. The results of the adsorption studies at various time intervals indicated that MKT had the capacity to adsorb Fe2+, Mg2+, Zn2+, Cu2+, and Pb2+ as follows: 1.90 ± 0.30 mg/g, 1.80 ± 0.20 mg/g, 1.40 ± 0.20 mg/g, 0.10 ± 0.01 mg/g, and 0.05 ± 0.01 mg/g, respectively. Thus, Fe2+, Mg2+, and Zn2+ were quantitatively removed from the aqueous solutions, whereas Cu2+ and Pb2+ were not. The adsorption of Fe2+, Mg2+, Zn2+, Cu2+, and Pb2+ by MKT from the aqueous medium was dependent on certain factors such as pH, temperature, adsorbent dosage, contact time, and initial metal-ion concentration.

The kinetic studies on the recovery of UO22+ and Pb2+ from aqueous solutions into chloroform solution of N,N’-ethylenebis(4-butanoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-oneimine) schiff base H2BuEtP has been investigated and the rate of reaction found to be first order with respect to both metal ions (UO22+ and Pb2+). The rate of extraction was equally dependent on the inverse of hydrogen ion concentration for both metal ions. The rate constant Kf was equally calculated from intercepts of plots to be 0.491min-1 for UO22+ and 0.411 min-1 Pb2+ metal ions. Optimum percentage extraction of 99.714% was observed for Pb2+ metal ion at 30mins equilibration time and 98.216% for UO22+ metal ion at 20mins equilibration time. The study on mechanism of extraction for the metal ions from the aqueous phase into the organic phase showed that the formation of the first chelate ring of mono-pyrazolonato metal complex is the rate determining step which involved a slow bond-weaking effect by the bidendate H2BuEtP on the water molecule.