SEQUESTRATION OF METHYLENE CHLORIDE ON TO ACTIVATED SNAIL SHELL CARBON, ORDINARY CLAY AND ACTIVATED CLAY

ABSTRACT

Comparative Adsorption efficiency of methylene chloride was carried out on activated snail carbon, ordinary clay and activated clay. A batch adsorption experiment was carried out at variable concentration, time, pH, temperature and adsorbent weights while other factors are kept constant. The result showed that that activated clay proved to has the highest adsorption efficiency, followed by ordinary clay and active snail shell carbon. The kinetics of adsorption of methylene chloride onto activated snail shell carbon, ordinary clay and activated clay were studied using pseudo-first- order and pseudo-second-order equations for the examined systems. The pseudosecond-order provided best correlation for the experimental data .Langmuir, Freundlich and Harkin-Jura Isotherm models were used to described the adsorption isotherm, Freundlich models gave a better fit; R2=0.9921, R2=0.9944 and R2=0.9952 for adsorption of methylene chloride on activated snail shell carbon, ordinary clay and activated clay respectively, which showed favourable adsorption. From the thermodynamic studies, ∆𝐻 values were found to be 16.61,14.21 and 19.57 KJ/mol also ∆𝑆 were 58.43,51.2 and 70.15 J/molK for adsorption of methylene chloride on activated snail shell carbon, ordinary clay and activated clay respectively, which shows that the adsorption is an endothermic and a physical process as well structural changes took place at the solid-liquid interface which favours adsorption .From the Scanning Electron Microscope (SEM) Analysis, at 10000x magnification, ordinary clay has pore size of 20 µm and activated clay has a pore size of 50 µm representing higher surface area thereby validating the fact that activated clay has greater adsorption capacity than ordinary clay.