A pilot scale evaluation for adsorptive removal of lead (II) using treated granular activated carbon.

Wastewaters discharged from the defence serviceable industries pose a serious environmental hazard due to their heavy metal load. The present study focused on optimizing the operational variables viz, hydraulic loading rate, bed height and feed concentration through bench scale study and using that for assessing the efficiency of pilot scale system with sulphur loaded carbon (AC-S) as the adsorbent in the removal of Pb (II). Static mode adsorption studies were also carried out for Pb (II) removal using treated (AC-S) and untreated carbon (AC). AC-S shows about 35 percent increase in maximum adsorption capacity over that on AC. The maximum adsorption capacity in the column mode for Pb (II) at the optimized conditions: bed height of 0.4 m, hydraulic loading rate of 7.5 m3h(-1)m(-2) and the feed concentration of 6 mg l(-1) for achieving 50% breakthrough concentration was found to be 2.89 mg g(-1). Adsorption mechanism involved during Pb (1) in the column has also been explored. Bohart-Adams model was used for modeling the bench scale data and predicting the adsorption behavior at pilot scale level.