In-situ confinement of ellagic acid within conjugated microporous poly(aniline)s for efficient capture mercury (II)

Abstract

In practical wastewater treatment, microporous polymers and polyphenolic materials often suffer from limited adsorption performance for heavy metal ions, primarily due to the restricted pore structure of the former and the poor chemical stability of the latter. Herein, a novel EA@CMPA composite is developed via in-situ confinement of ellagic acid (EA) within Conjugated Microporous Poly(aniline) (CMPA) for efficient Hg(II) removal. EA is anchored within CMPA through dual interactions: (i) hydrogen-bonding and (ii) protonation. This design endows the composite with hierarchically structured mesoporous diffusion channels and abundant active adsorption sites, thereby enabling EA@CMPA to enhancement of the adsorption kinetics and capacity. The resulted EA@CMPA(200) has high Hg(II) adsorption rate h of 640 mg g^-1 min^-1 and adsorption capacity of 1024 mg g^-1. Notably, EA@CMPA maintains a regeneration efficiency over 81.5% after 7 cycles of intensive reuse, demonstrating that the water-soluble ellagic acid is efficiently confined within the pore channels. It also exhibits excellent anti-interference ability and selectivity in actual Hg-containing wastewater, with Hg(II) removal rate of 95.41% and selectivity approaching 100%. The adsorption behavior and mechanism are characterized by FT-IR, XPS, and DFT calculations, revealing that the synergistic interactions between C=O and –NH– sites drive superior Hg(II) capture. This study highlights the potential of EA@CMPA as a high-performance adsorbent for mercury remediation.