Separation Science and Technology, Vol.49, No.16, 2557-2567, 2014
Use of Low Cost Cellulosic Biopolymer Based Adsorbent for the Removal of Toxic Metal Ions from the Aqueous Solution
Cellulosic biofibers because of their abundance and renewable nature have recently attracted the attention of researchers for their applications in the field of waste-water remediation. In the present study, cellulosic biofibers have been modified through alkali treatment and subsequently used as low cost adsorbent for the removal of Cu2+, Zn2+, Cd2+, and Pb2+ toxic metal ions from aqueous solution. Both raw and treated fibers have been characterized by scanning electron micrography (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric (TGA), and X-ray diffraction (XRD) techniques. Various adsorption parameters such as pH, contact time, temperature, and initial metal ion concentration were studied. The adsorption has been found to depend on the pH of the solution. The Langmuir and Freundlich isotherm models were used to show the adsorption isotherm. The Langmuir model fitted well with the equilibrium data. The maximum adsorption capacity calculated using Langmuir model for Cu2+, Zn2+, Cd2+, and Pb2+ metal ions at 25 [GRAPHICS] has been found to be 19.21, 16.85, 44.42, and 67.24 mg/g, respectively. Adsorption of metal ions has been observed to follow the pseudo-second-order kinetic model, rather than pseudo-first-order-model. Further temperature study has revealed that the adsorption process is exothermic in nature.