Removal of Heavy Metals from Waste Water Using Black Teawaste

Removal of heavy metals (Cobalt, Cadmium, and Zinc) from waste water was possible using black teawaste. Adsorption was observed for the three metals at 180 min. Under our experimental conditions, pH plays an important role in the adsorption process, particularly on the adsorption capacity of teawaste for the heavy metals under study. The pH level allowing for an optimum rate of adsorption was found to be 6 for Co, Cd, and Zn. We demonstrate that black teawaste has a relatively high adsorption capacity for these heavy metals; the quantities adsorbed per a half gram of black teawaste at equilibrium (q (e)) are 15.39 mg/g for Co, 13.77 mg/g for Cd, and 12.24 mg/g for Zn. It was found that the percentage of removed metal ions is inversely proportional to initial metal ions concentration, but correlates with teawaste adsorbent dosage. The adsorption of heavy metals on black teawaste is described by an isotherm of type I and is fully verified by the Freundlich and Langmuir isotherms. The kinetics of the Cobalt, Cadmium, and Zinc adsorption on the teawaste were found to follow a pseudo first-order rate equation. This method has the advantage of being applicable in developing countries due to the low cost and availability of teawaste.