Kinetics and Mechanism of the Adsorption of Lead (II) Ions on Aluminium (III) Oxide Powder

Adsorption is adhesion of a chemical species on the surface of adsorbents particles. In general adsorption can be defined as accumulation or, depletion of solute molecules at an interface. Lead is one of the most toxic heavy metals, is attracting wide attention of environmentalists due to its acute and chronic toxic effects in animal and human health. Alumina is one of the most widely used ceramics due to its high specific surface area, very good thermal stability and amphoteric properties. A R grade lead nitrate (Pb(NO₃)₂) (99.0% purity) and alumina (Al₂O₃) (99.9% purity) were used as adsorbate and adsorbent respectively for study. The present study was carried out to evaluate feasibility of aluminium (III) oxide powder for the removal of Pb(II) ions from aqueous solution through batch adsorption process. The effects of adsorbent dose, contact, time, concentration, temperature and pH value of the adsorbate were studied. The percentage amount adsorbed increases with increase in dilution and pH value. On the other hand decreases with the rise of temperature. The percentage amount adsorbed is optimum for 0.1 mole l^-1 concentration, 298K temperature and pH value of 8.5. The decrease of adsorption with increase in temperature indicates the process of adsorption is physical in nature. The present research work describes the kinetics and mechanism of the adsorption process in details.