High-Throughput Pb Recycling for Perovskite Solar Cells Using Biomimetic Whitlockite

Pb contamination in aquatic environments causes severe pollution; therefore, harmless absorbents are required. In this study, we report a novel synthesis of whitlockite (WH, Ca18Mg2(HPO4)(2)(PO4)(12)), which is the second most abundant biomineral in human bone, and its application as a high-performing Pb2+ absorbent. Hydroxyapatite (HAP) and WH are prepared via a simple precipitation method. The Pb2+ absorption performance and mechanism of the synthesized biominerals are investigated in aqueous solutions at neutral pH. The results demonstrate that WH exhibits an excellent Pb2+ absorption capacity of 2339 mg g(-1), which is 1.68 times higher than the recorded value for HAP. Furthermore, the absorbed Pb2+ ions are recycled into high-purity PbI2. This is employed as a precursor for the fabrication of perovskite solar cells (PSCs), resulting in a conversion efficiency of 19.00% comparable to that of commercial PbI2 powder (99.99% purity). Our approach provides an efficient way to remove Pb2+ ions from water and reuse them in the recycling of PSCs.