Novel hierarchical ionic polymers for removal of perfluorooctane sulfonate and dichromate

[Display omitted] •A novel ionic polymer is developed for removal of dichromate and perfluorooctane sulfonate with high efficiency in water.•The ionic polymer exhibits high adsorption capacity, selective adsorption and recycling stability toward PFOS and dichromate.•The adsorption mechanism for synchronous removal of dichromate and perfluorooctane sulfonate has been proposed. The development of porous adsorbents for removal of concomitant perfluorooctane sulfonate (PFOS) and dichromate pollutants is pivotal and challenging in wastewater remediation. Herein, we presented a leaf-inspired artificial cleaning system based on an ionic polymer (ImIP-6) with high local density of imidazolium moieties and charge-balanced chloride for efficiently simultaneous removal of PFOS and dichromate. ImIP-6 exhibits fast kinetics and ultrahigh uptake capacities with maximum adsorption values of 2606 mg g−1 for PFOS and 247 mg g−1 for Cr(VI), which are far superior to many porous sorbents. The mechanism studies have evidenced that ImIP-6 possesses two types of domains for PFOS and dichromate adsorption, in which the imidazolium-based cationic surface induces PFOS enrichment and subsequent formation of micelles on the outer surfaces without significantly interfering the adsorption of dichromate in the interior pores. This work provides one new approach based on biomimetic systems with hierarchical adsorption domains for wastewater remediation.