Adsorption of chromium from aqueous solution on treated sawdust

The adsorption of Cr(VI) from aqueous solutions on formaldehyde treated sawdust (SD) and sulphuric acid treated sawdust carbon (SDC) of Indian Rosewood, a timber industry waste, was studied at varying Cr(VI) concentrations, adsorbent dose, pH and agitation time. Similar experiments were conducted with commercially available coconut based activated carbon to compare the results. The Cr(VI) adsorption efficiency on SDC was higher than SD. The adsorption followed first order rate expression and Lagergren equation. An initial pH of 3.0 was most favorable for Cr(VI) removal by both the adsorbents. Maximum Cr(VI) was sequestered from the solution within 60 min after the beginning for every experiment. It is proposed that SDC and SD can be potential adsorbents for Cr(VI) removal from dilute solutions.