Sustainable Recovery of Rare Earth Metals from Smartphone Display using Nanoengineered Cellulose

Recycling rare earth elements (REEs) from electronic waste has gained significant attention over the last decade. A sustainable, fast, and selective extraction technique for rare earth metals hardly exists despite that. This work shows a selective rare earth metal recovery from a mobile phone display using a carboxylate functionalized cellulose (CFC). The nanoengineered CFC is water-dispersible and prepared from affordable, readily available cellulose precursor. It is shown that the REEs present in the mobile phone display instantaneously form a precipitate with CFC, which is easily separated by centrifugation. As low as 150 ppm, the total concentration of REEs in the leachate is required to form a precipitate. The total removal capacity of the REEs in the leachate is 252 +/- 4 mg per gram of CFC. In addition, the precipitate formation occurs within 10 s, which to our knowledge, is the best-reported removal time so far. It is observed that when the total concentration of the REEs in the leachate is 150 ppm or above, the removal capacity of CFC is quite efficacious and unperturbed by the presence of other metal ions. Solar electrodeposition method is utilized to recover rare earth metal and their oxide from the precipitate.