Abstract
In this paper, the results of a study on removal of copper from synthetic aqueous solutions as well as from industrial wastewater by adsorption onto Casuarina Equisetifolia bark have been reported. Experiments were conducted to understand the effects of particle size, adsorbent dosage, pH, initial concentration, and contact time on the adsorption of Cu(II) on the bark. Quantitative removal of Cu(II) from a solution containing 10 mg/L Cu(II) by 2 g of 0.6 mm particle size of Casuarina Equisetifolia bark per liter was observed for 6 h with a pH value of around 5 and the percentage removal was higher at lower concentration. It has been established that the adsorption isotherm follows both Frieundlich and Langmuir isotherms. The adsorption capacity of Casuarina Equisetifolia bark was estimated as 16.58 mg/g for a concentration of 10 mg/L at pH being equal to 5 and the removal efficiency Cu(II) ion was found to be about 96%. The results also revealed that the retention capacity of the bark is reduced during each cycle, and the Cu(II) ion removal efficiency decreases when other metal ions were present in the solution. The suitability of Casuarina Equisetifolia bark for treating electroplating wastewater containing copper was tested through column experiments and it was found that the removal efficiency of Cu(II) from this waste water is about 93%. The regeneration study established that the bark can be used continuously without much reduction in removal efficiency and without any significant leaching of adsorbed Cu(II) ions.