来源：ACS Publications
The efficient recovery of rare-earth elements (REEs) from wastewater is crucial for resource utilization and environmental protection. Developing adsorbents with green fabrication processes, biodegradability, and carbon circularity is of great significance for achieving a sustainable wastewater treatment and resource recovery. In this study, a fully biobased phosphorus-rich microsphere (PA@CS) was prepared through a simple one-step cross-linking reaction to selectively adsorb heavy rare earth elements (HREEs). The adsorption kinetics were described by the pseudo-second-order model. Meanwhile, the Freundlich model well described the adsorption isotherm, where phosphate and hydroxyl groups contributed to REE adsorption, and phosphate groups served as the dominant binding sites. The maximum adsorption capacities of PA@CS for Dy(III), Ho(III), Lu(III), and Tb(III) were 167.4, 168.6, 139.4, and 136.7 mg/g, respectively. The presence of Na(I), Mg(II), or Nd(III) has a minor effect on the adsorption of the REEs. The XGBoost model and Shapley additivity analysis well predicted the importance of factors influencing adsorption capacity: contact time > initial concentration > ionic radius > pH > electronegativity. Building on this, SHAP interaction analysis revealed that the synergistic effects between the initial concentration and ionic radius were the dominant contributors to adsorption performance, followed by the synergy between pH and adsorption time. The desorption efficiency reached 92.89%, and the spent PA@CS was almost degraded after 21 days of burial in soil. This work reports a biodegradable adsorbent for HREE recovery using a facile preparation method and employs SHAP-based machine learning for a rational mechanistic study, shedding light on renewable resource utilization and potential closed-loop recycling.