Mercury(II) Removal by Bicarbonate Modified Tamarindnut Carbon

Abstract

The carbon obtained by treatment of tamarindnut with concentrated sulphuric acid under a weight ratio of 1 : 1 followed by soaking in 10% sodium bicarbonate solution exhibited a significant removal of Hg(II) from aqueous solutions over the pH range of 3–10 and commercially activated carbon in the pH range of 2–3 in batch studies. Based upon the findings, column studies were mainly conducted under optimum conditions to evaluate the removal of Hg(II) for large scale applications. For bicarbonate modified tamarindnut carbon an optimum flow rate of 13 mL/min with optimum bed height of 10.3 cm in 2.5 cm diameter column with optimum weight of 15 g of carbon was maintained. In the case of commercially activated carbon, 15 g of carbon with optimum flow rate of 5 mL/min was maintained with the optimum bed height of 5.8 cm. The breakthrough capacities of bicarbonate modified tamarindnut carbon and commercially activated carbon under optimum conditions were found to be 1440 and 52 mg respectivey per 15 g of carbon. Common anions and cations affected the removal of Hg(II) on both the carbons. Breakthrough capacities were found out in the presence of wastewater containing Hg(II) and the potential of bicarbonate modified tamarindnut carbon was found to be 10 times superior to commercially activated carbon in the removal of Hg(II).