LAUSR

Sequestration of heavy metal ions from water is an important issue in chemistry. Herein, we report the detailed Pb2+ adsorption and ion exchange kinetics of a potassium intercalated layered metal thiophosphate, K0.48Mn0.76PS3.H2O (K-MPS-1), which is capable of efficient removal of Pb2+ (>99%) from very dilute concentrations (1–100 ppb). K-MPS-1 can selectively capture Pb2+ even in the presence of other monovalent and divalent cations such as Na+, Ca2+, and Mg2+ with high separation factor. K-MPS-1 can operate within a broad pH range of 2–12 effectively with high distribution coefficient (KdPb) of 5.36 × 105 mL/g, following pseudo second order kinetics. Initially, K+ intercalation in MnPS3 (MPS-1) increases the interlayer spacing and subsequently creates Mn2+ vacancy to maintain charge neutrality and destroy the center of symmetry of the P2S6 unit. Finally, Pb2+ kicks out K+ ions from the interlayer and sits into Mn2+ vacant sites in MPS-1 which further helps to regain the center of symmetry of the structu...