Chlorine anchored pyrrole-based conjugated porous polymers for ultrahigh capacity and selective Hg(II) capture

In this study, chlorine anchored pyrrole-based conjugated porous polymers (CPPs) with distinct pore properties were synthesized using the Knoevenagel reaction and the double chain condensation method. The partially crosslinked and partially oxidized structures of the materials exhibit a unique microstructure integrating interconnected nets and molecular hooks. This architecture utilizes pore channels for physical interception of Hg(II), while synergistic chemical immobilization at N, O, and Cl active sites enables multifunctional enhancement of Hg(II) capture efficiency. Among these materials, the maximum adsorption capacity reached 1183 mg·g⁻¹, demonstrating ultrahigh selectivity. Moreover, the adsorbents maintained > 90 % removal efficiency over 10 adsorption–desorption cycles, confirming excellent reusability. Mechanistic studies revealed that Hg(II) adsorption primarily whin material pores through hydrogen bonding and coordination interactions, and their synergistic interactions. This work highlights the efficiency of the double chain condensation design strategy in advancing conjugated porous polymers for the removal of heavy metals, particularly Hg(II), from wastewater.