Efficient removal of Pb2+ and Cd2+ using a Cu(i)–Br coordination polymer constructed with an amino-rich ligand

Abstract

In this work, a Cu(I)–Br coordination polymer Cu₂Br₂(MA)₂ (1) (MA = melamine) with an amino-rich ligand was synthesized and applied for the removal of Pb²⁺ and Cd²⁺ successfully. The effect of various parameters like pH, initial metal ion concentration, and contact time on the adsorption performance of 1 was investigated. The adsorption of Pb²⁺ and Cd²⁺ were in good agreement with the pseudo-second-order kinetic model and Langmuir isotherm model. The maximum adsorption capacities for Pb²⁺ and Cd²⁺ were 598.8 mg g⁻¹ and 2175 mg g⁻¹ at 298.15 K, respectively. The high adsorption capacities were attributed to the coordination interaction between the amino groups of melamine molecules and Pb²⁺ and Cd²⁺ ions. Moreover, the adsorption performance of Pb²⁺ and Cd²⁺ ions showed no obvious decrease even after six cycles.