Biosorption of Toxic Hexavalent Chromium from Aqueous Solutions by Low-Cost Waste Biomaterial

Chromium metal has unique properties and therefore finds large number of applications in industries like chrome-plating, steel and alloy, leather tanning and ammunition factories. These industries consequently, discharge large quantities of hexavalent chromium (Cr6 ) containing effluents. Since chromium is toxic to all life forms, its removal from effluents is the key. Conventional processes used are highly energy-intensive and economically unattractive. Biosorption, a technically feasible and economical process has gained immense creditability in the recent years. The present study explores the possibility of using biosorption process for the removal of Cr6 from aqueous solutions using low-cost biomaterial viz. saw dust (SD). Optimum parameters for maximum biosorption of Cr6 (10 mg/L) were as follows: pH 1-4, contact time 60 min and biomass quantity of 1 g/10 mL. Biosorption conformed to the Langmuir and Freundlich adsorption isotherms (R2 = > 0.97). It was found that the equilibrium sorption capacity of the sorbent increased with increasing initial concentration of Cr6 from 5 to 300 mg/L. Overall, the study showed that SD has immense potential as “biomaterial” for its use in the removal/recovery of hexavalent chromium from aqueous industrial solutions