High selectivity and reusability of coordination polymer adsorbents: Synthesis, adsorption properties and activation energy

The effective treatment and recovery of Au(III) was a major challenge facing the world. In this study, a new type of coordination polymer adsorbent (Zr-DBMA) was synthesized and its ability to adsorb Au(III) was evaluated. Zr-DBMA shows an outstanding Au(III) removal effect in the solution pH 2–9, due to protonation. The adsorption reached equilibrium within 60 min and the maximum adsorption capacity was 570 mg g−1 at 298 K. The adsorption complied with pseudo-second-order and Langmuir models. Thermodynamic experiment illustrated that the reaction was a spontaneous endothermic behavior. The adsorption activation energy (Ea) was 47.83 kJ mol−1. These indicated that the adsorption behavior was a single-layer chemical adsorption. Competitive adsorption and adsorption-desorption experiments showed that Zr-DBMA had considerable selectivity and reusability for Au(III). N/O functional groups absorbed Au(III) on the surface of Zr-DBMA through electrostatic attraction, chelation and reduction. These results indicated that Zr-DBMA had broad prospects in removing Au(III) from solution.