Quantitative Elimination of Cadmium Metal from Contaminated Waters by Albizia lebbeck as Bio-adsorbent

The removal of toxic metals, like cadmium (Cd) from wastewater in a convenient way is through low-cost bio-adsorbents. In this work, seeds of Albizia lebbeck (Indian siris) were applied for the adsorptive removal of Cd metals from an aqueous solution as a low-cost adsorbent. Researchers performed a batch experiment to observe the impact of pH, temperature, initial metal ion concentration, adsorbent dose, contact time and mixing speed on the bio-adsorption of cadmium (Cd) by Albizia lebbeck (seed). Both the Freundlich and Langmuir isotherms were well suited to the experimental data to determine the adsorption efficiency of organic and inorganic compounds on a wide variety of adsorbents at equilibrium. The heavy metal analysis was characterized by atomic absorption spectroscopy (AAS), that is amount of removed material by adsorbents through several batch experiments. The adsorbed amount was evaluated by the difference between initial concentrations and final concentrations of metal ion solution (mg/L). The removal efficiency of Cd metal was strongly dependent on its initial concentration, contact time, pH and temperature of adsorbents. The result showed that the sorption capacity increased with the initial adsorbate concentration, which was pH-dependent. The rate of metal-binding with biomass was predominant during the initial stages, which gradually decreased and remained almost constant after equilibrium time. Adsorbent got involved in metal complexation at active adsorption sites as early as the adsorbent was introduced into the system.