Removal of multiple metals using Tamarindus indica as biosorbent through optimization of process variables: a statistical approach

Abstract

In the present study, biosorption capacity of Tamarindus indica is investigated for removal of lead and zinc. The heavy metals, namely lead and zinc, are successfully removed from aqueous solution by batch biosorption using Tamarindus indica as biosorbent. The removal percentage of selected metals, namely lead and zinc, was improved through optimization of variables using response surface methodology (RSM). The conditions obtained with RSM are agitation time of 47.65 min, initial metal ion concentration of 46.49 mg/l, biosorbent dosage of 1.23 g and pH of 7.64 for lead biosorption, whereas those for zinc are agitation time of 22.84 min, dosage of 0.78 g, initial ion concentration of 20.87 mg/l and pH of 6.98. The maximum of 83.52% removal of lead was achieved and for zinc 63.7%. Heavy metal biosorption ability of biosorbent has been qualitatively characterized using Fourier transform infrared spectroscopy and scanning electron microscopy analysis. This study reveals that the Tamarindus indica efficiently removes heavy metals. The biosorption kinetic study at RSM optimized conditions exhibited better fit to Freundlich isotherms (R2 0.993) for lead than Langmuir isotherm (R2 0.974).