Hyperbranched phosphate functionalized covalent organic framework for high-performance recovery of 177Lu from wastewater

The disposal of medically radioactive wastewater is an important issue of radiochemistry and nuclear technology. 177Lu (T1/2 = 6.65 d), with a half-life approximately one week, has received constantly increasing application in modern medicine, which is leading to growing costs about radioactive waste storage and potential environmental risk related to radioactivity leakage. In this work, we proposed applying hyperbranched modification to prepare phosphate functionalized covalent organic frameworks (COFs) with potential in removing radioactivity decontamination of medical wastewater. TpBD-O-(OP)n has been well prepared using a stepwise strategy, which exhibits abundant active sites, excellent stability and high affinity towards 177Lu. As a result, TpBD-O-(OP)n purification columns present good stability and versatility in practical radioactive 177Lu wastewater treatment. More importantly, extended X-ray absorption fine structure (EXAFS) results probe that hyperbranched modification can endow the obtained materials with high-density functional groups, available for capturing trace-amount 177Lu from aqueous solution via cooperative coordination. This work not only provides a feasible material for 177Lu separation and removal, but also presents an effective strategy for designing functional COFs towards general radioactivity decontamination.