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

Author(s): Nilisha P. Itankar and Yogesh B. Patil

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.

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