Solid sorbents for rare earths recovery from electronic Waste

Activated carbon (AC) and modified AC were tested as solid sorbents for Rare Earths (REs) recovery from Electronic Waste. The modified AC was synthesized by loading Pentaethylenehexamine and the amount of loaded polymer was estimated by COD analysis of the residual amount in solution. The AC and the modified AC were contacted with lanthanum solutions (chosen as representing element of REs family) and the lanthanum adsorbed by the solids was analyzed by ICP-OES of the contacted solution. Finally, release tests were performed on the different samples in order to verify the solids capability not only to capture but also to recover metal ions. The obtained results showed that the experimental procedure was appropriate to load the polymer onto the AC and that the modification of the AC improved both adsorption (from 44% to 100%) and release (from 65% to 91%) with respect to natural AC, ensuring a global recovery efficiency of 90%.