This study investigated a new area of improving the adsorption capacity of clay using corn cob as an alternative means of clay modification to the more expensive and complicated chemical treatment techniques. Kaolinite Clay (KC), Calcined corncob-kaolinite Combo (CCKC), and Corncob (CC) adsorbents were utilized. The adsorbents were characterized by Fourier Transform-Infrared (FT-IR) Spectroscopy, Scanning Electron Microscopy (SEM), X-ray fluorescence spectroscopy, and Brunauer-Emmett-Teller (BET) surface area analyzer. Batch adsorption methodology was used to investigate the effect of pH, initial metal concentration, adsorbent dose, and contact time on adsorption of Pb (II) and Cd (II). A slight increase in BET surface area of 29.31 m2/g for CCKC from 14.12 m2/g for raw KC was achieved. The trend of metal adsorption on the adsorbents was in the order CC>CCKC>KC. The Langmuir isotherm was found to present the best fit for the unmodified adsorbents while the Freundlich was applicable for CCKC indicating multilayer heterogeneous surface. The pseudo second order kinetic model was found to be suitable in the kinetic analysis. Thermodynamic studies revealed a spontaneous physical adsorption process of metal ions on CCKC. The combo adsorbent showed highest percentage desorption (>70%) of Cd and Pb ions in both acid and basic media compared to the other adsorbents. The results of the study established the efficiency of calcined corn cob kaolinite combo as suitable adsorbent for metal ions.

The prevention of deterioration of mild steel in 1.0M and 5.0M H2SO4 solution by leaf extracts of Pterocarpus santaliniodes was investigated in this study using gravimetric and gasometric methods. Data obtained from the study revealed that leaf extracts had a maximum inhibition efficiency of 88.70% and 96% for weight loss and gasometric analysis, respectively for 1.0M H2SO4, and an inhibition efficiency of 71.76% and 79.66% for weight loss and gasometric analysis respectively for 5.0M H2SO4. It was observed that the gasometric method gave the optimum protection. The average activation energy was 73.71KJ/mol in 1.0M H2SO4, and 74.41KJ/mol in 5.0M H2SO4. The adsorption of the phytochemicals on the surface of the mild steel were further assessed by the Langmuir and Freundlich isotherms. The extract was found to be good inhibitor for mild steel corrosion in the H2SO4 solutions. The amount of material loss decreased in the in the presence of the extract when compared to the blank acid solution.