The recovery of dysprosium(III) using a modified phosphorylated chitosan resin by rapid small-scale column testing...

The recent surge in demand for rare earth elements (REEs), essential for advanced technologies, coupled with supply chain challenges, has heightened interest in recovering these metals from alternative sources such as natural saline brine and wastewater streams. Water treatment methods facilitating REE recovery are economically viable and support the transition to a circular economy. In this communication, we report on the recovery of dysprosium(III) (Dy(III)) using a modified phosphorylated chitosan resin (PCs/MB) through rapid small-scale column testing. The optimal recovery conditions were identified, and the associated environmental impacts, from resin fabrication to the recovery process, were assessed. A maximum adsorption capacity (q_sat) of 22 mg/g was achieved under optimized conditions, with a Dy(III) feed concentration of 13 mg/L at pH 5.2. Additionally, the use of flow interruption improved the adsorption capacity of Dy(III), bringing it closer to the maximum adsorption capacity observed in batch studies. Complete recovery of Dy(III) from PCs/MB was achieved using 2 L/g of 0.001 M hydrochloric acid over three 12-h desorption cycles. Full recovery of Dy(III) and Nd(III) from a saturated adsorbent was similarly attained within 48 h, with a concentration factor of 1.8x in the first desorption cycle. A preliminary cradle-to-gate life cycle assessment (LCA) of biomass-based PCs/MB production predicted 2.6 times lower energy consumption and substantial reductions in global warming potential (GWP), acidification potential (AP), and eutrophication potential (EP) compared to fossil fuel-derived styrene-based resins. This environmental impact assessment highlights the potential of this method as a sustainable approach for REE recovery.