The improvement of the adsorption capacity of clay minerals using chemicals though effective is expensive, results in secondary contamination and noxious to the environment. This study was therefore aimed at the development of a new sawdust clay modified adsorbent (SDKC) as an alternative means of improving the adsorption capacity of kaolinite. The adsorbents were characterized by the Fourier transform infrared spectroscopy and X-ray diffraction analysis. Batch sorption was employed to determine the effect of pH, metal concentration, sorbent dose, time and temperature on the removal of Pb (II) and Cd (II) ions from solution by the adsorbents. Optimum operating conditions of pH 6.0, metal concentration 200mg/L, sorbent dose 0.1g was obtained. Equilibrium isotherm analysis indicated the Langmuir, Temkin and Flory-Huggins models to be more suitable than the Freundlich, Dubinin–Radushkevich (D-R). The kinetic data were analyzed using the pseudo-first order, pseudo-second order, the Elovich and intraparticle diffusion models. The analysis revealed that the adsorption process followed pseudo second order model. The calculated thermodynamic parameters showed an endothermic, spontaneous and a physisorption process between both metal ions and the adsorbents. The obtained result of the experiment indicated a significant improvement in the uptake of Pb (II) and Cd (II) ions on the sawdust modified kaolinite adsorbent than the untreated kaolinite clay. This could be utilized as an alternative to chemical treatment methods Bangladesh J. Sci. Ind. Res.54(1), 99-110, 2019

The effect of iodide ions on the inhibitive performance of ortho, meta and para nitro aniline in 1M HCl for mild steel has been studied using weight loss method (gravimetric) measurements at 303 and 333K. Results obtained show that the presence of the nitro aniline compounds in 1M HCl solution inhibits the corrosion process of mild steel. Its adsorption was found to be physical, exothermic and spontaneous as confirmed by values of activation energy and free energy of adsorption (not up to −20 kJ mol −1 for free energy of adsorption and below 80 kJ mol −1 for activation energy) and also fitted the Langmuir adsorption model. Addition of iodide ions synergistically increased the inhibition efficiency of the nitro aniline compounds. Quantitative Structure Activity Relationship (QSAR) approach was used on a composite index of some quantum chemical parameters. The results showed that the Inhibition Efficiency was closely related to some of the quantum chemical parameters.