EFFECTS OF PHYSICO-CHEMICAL PROPERTIES OF WETLAND SOIL ON THE ADSORPTION OF CADMIUM IONS

Abstract

This work investigated the effect of soil Surface, Soil morphology and broken edge of fadama clays collected from three different locations in Niger Delta on the adsorption of Cadmium ions. The particle size, the contact time, the total organic matter, the pH, and the adsorbent concentration of the different soils were evaluated. These Soils were prepared to adsorb Cadmium from aqueous solution of different pH, time and adsorbent concentration. The adsorption behaviors that were characterized, using Adsorption isotherms, Adsorption kinetic, adsorption edge and Diffusion – Chemisorptions show that Soil from Patani (FAP) yielded maximum adsorption capacity for Cadmium at lower pH 2, followed by soil from Uwherun (FAU)and Soil from kokori the least(FAU). Adsorption capacity decreases with increase in pH values in the three soil samples (except for FAK that increases at pH 4) which is in line with [1] that says that in ion exchange mechanism, Cadmium binds to anions sites by displacing protons from acidic groups or existing alkali earth metal e.g Na or Ca from anionic sites at high pH. This suggest that there is surface and broken edges OH groups that gives the fadama clay particles their electro negativity and their capacity to adsorbed cadmium ions. Application of Diffusion Chemisorptions rate (KDC) for cadmium ions indicated that Fadama clay from Patani (FAP) had the highest Diffusion Chemisorptions rate (KDC) followed by Kokori (FAK) and Uwheru (FAU) the least. This was as a result of available surface area and reduced distance for the sorbate to travel to reach the active Sorption site.