Removal and Recovery of Chromium from E-waste by Functionalized Wood Pulp: A Green Bio-hydrometallurgical Approach

摘要

Functionalized wood pulp (WP-g-GMA-d-GluN(+)) as biosorbent and dl-malic acid-hydrogen peroxide as leaching agent was used for the recovery of chromium [Cr(VI)] from e-waste (waste floppy disks) in this study. Presence of N-content in WP-g-GMA-d-GluN(+) (8.013%), relative to pristine wood pulp, was achieved by C-H-N elemental analysis. Functionalized biosorbent was characterized through standard analytical tools (Fourier transform infrared spectroscopy, scanning electron microscopy, and thermo-gravimetric analysis). Cr(VI) concentration in leachate before and after uptake was measured by atomic absorption and UV-VIS spectrophotometer. Maximum Cr(VI) recovery from floppy disks was found to be 98.25%; 24.5625mgg(-1) at room temperature for an initial Cr(VI) concentration of 25mg l(-1) at pH 2.5. Organic acid regeneration was tried for several cycles with a view to recover the sorbed Cr(VI) and also to restore the biosorbent to its original state. The successful application of easily abundant wood pulp as a biosorbent has potential for a low technological pre-treatment step prior to economically not-viable, high-tech chemical treatments for the removal of Cr(VI) from e-waste.