SIMULTANEOUS ADSORPTION OF LEAD (II), CADMIUM (II) AND MANGANESE (II) IONS FROM INDUSTRIAL WASTEWATER ONTO DIJAH-MONKIN NATURAL BENTONITE CLAY
Pollution posed by toxic heavy metals contamination as a result of industrial activities is at the increase and it has devastating effects on human and the environment at large. Activated carbon used as adsorbent has been successful in the treatments of toxic heavy metal ions from aqueous solutions although expensive. Therefore, the need for a safe, effective and low cost technology. As a result of the aforementioned, the potential of the Dijah-Monkin bentonite as adsorbent for the removals of Pb (II), Cd (II) and Mn (II) were investigated in a multi-component aqueous solution in batch mode. Characterization of the bentonite showed that the major components in the clay were silica (62.30 wt%) and alumina (21.00 wt.%). In addition, the specific surface area and cation exchange capacity were 23.50 m2/g and 47.70 mEq/100g respectively. The surface morphology and the micro structure of clay showed the presence of pores that can allow favourable sorption to take place. The percentage removal of the metal ions were 58%, 27% and 15% for Pb (II), Cd (II) and Mn (II) respectively in the order: Pb (II) > Cd (II) > Mn (II). The equilibrium isotherm and kinetics studies of the data obtained revealed that the Langmuir model and the pseudo second order kinetics better described the adsorption process.