The Preparation and Palladium Adsorption Properties of Thiophene-crown Ether-based Covalent Organic Polymers
The unique physical and chemical properties of the precious metal palladium(Pd)enable it to play a key role in fields such as catalysis,new energy sources,medicine and environmental protection.Global reserves of palladium ore are scarce and non-renewable,so the separation and recovery of palladium is of great significance to the realization of sustainable development and the recycling of resources.Two covalent organic polymers(COPs):B-18C6-COP and B-24C8-COP,with trithiophene groups and crown ether groups as backbones,were prepared by the Schiff base reaction,and the adsorption properties of the two materials for palladium ions were evaluated by the static adsorption method.The results showed that B-18C6-COP and B-24C8-COP exhibited better stability under acidic conditions,and the adsorption capacities for palladium ions were 109.41 mg/g and 96.26 mg/g at 1 mol/L HNO3,respectively.Meanwhile,both materials showed high selectivity for palladium ions when coexisting with 10 other competing ions.This work provides a class of adsorbents with excellent selectivity to palladium ions,and provides a new idea for the recycling of palladium ions.