Bottom-up synthesis of cationic porphyrin-based porous organic polymers for highly efficient and selective recovery of gold.

[Display omitted] • A new cationic imidazolium and porphyrin cross-linked POP was prepared by the bottom-up method. • The Imi-PPOPs-Br exhibited considerable Au (III) adsorption capacity (1543 mg g−1). • The mechanism was ascribed to the electrostatic interaction, strong binding and reduction. • The Imi-PPOPs-Br owns superior selectivity towards gold for the CPU leaching solution. • The Imi-PPOPs-Br possesses great recyclability and practical application potential. Developing ionic porous organic polymers (i-POPs) to retrieve gold from electronic waste is still in its infancy. Herein, for the first time, a cationic imidazolium and porphyrin cross-linked POPs, Imi-PPOPs-Br, was constructed by combining pyrrole and imidazolium-functionalized trialdehydes via the bottom-up method. As expected, the introduction of cationic imidazolium and porphyrin rings has endowed material high adsorption capacity (1543 mg/g), preferable reusability (more than eight times), and specific selectivity to Au (III). Multiple characterization results and density functional theory (DFT) calculations revealed that the adsorption mechanism of Au (III) by Imi-PPOPs-Br could be due to the electrostatic interaction between cationic Imi-PPOPs-Br and AuCl 4 − anions, strong bind of Au and N active sites, and reductive immobilization of Au (III) to Au (0). This study may put forward a new and facile strategy for constructing stable i-POPs that can be used as desirable absorbents in environmental fields. [ABSTRACT FROM AUTHOR]