Fixed bed column study for Cd(II) removal from wastewater using treated rice husk.

A fixed bed of sodium carbonate treated rice husk was used for the removal of Cd(II) from water environment. The material as adopted was found to be an efficient media for the removal of Cd(II) in continuous mode using fixed bed column. The column having a diameter of 2 cm, with different bed depths such as 10, 20 and 30 cm could treat 2.96, 5.70 and 8.55 l of Cd(II) bearing wastewater with Cd(II) concentration 10 mg/l and flow rate 9.5 ml/min. Different column design parameters like depth of exchange zone, adsorption rate, adsorption capacity, etc. was calculated. Effect of flow rate and initial concentration was studied. Theoretical breakthrough curve was drawn from the batch isotherm data and it was compared with experimental breakthrough curve. An amount of 0.01 mol/l HCl solution was used for desorption of adsorption column. Column regeneration and reuse studies were conducted for two cycles of adsorption-desorption.