Adsorptive removal of Lead from aqueous solution using Raw and Modified Shea Butter Cake (MSBC)

Abstract

The adsorption of lead (Pb) from aqueous solution using Raw Shea Butter Cake (RSBC) and Modified Shea Butter Cake (MSBC) was studied. Fourier Transform-Infrared Spectrophotometer (FT-IR) and Scanning Microscope (SEM) were used to characterize the adsorbent. The chemical functional groups responsible for metallic bio-sorption were the –OH, -COOH and –NH2. Batch adsorption process was used to study the effect of various parameters ranging from the effects of initial metal ion concentration (10-400 mg/L), pH (2-10), and equilibrium time (0-240 minutes). Optimum conditions of initial metal ion concentration = 250 mg/l, pH = 6 and equilibrium time = 5 min for MSBC and 30mins for RSBC were obtained. Adsorption isotherms, namely Langmuir, Freundlich, Temkin, and Dubunin- Radushkevich (D-R) were found to fit the experimental data adequately well. The Langmuir Isotherm gave the best fit with the highest correlation coefficient of 0.9996 for MSBC and maximum sorption capacity of 13.175 mg/bead, while the corresponding values of 0.9998 and 9.328 mg/g were observed for RSBC. The results obtained showed that both the RSBC and MSBC have the potential to serve as adsorbent for the removal of Pb(II) ions in aqueous solutions.