Processable hypercrosslinked ionic networks for effective removal of methyl orange

[Display omitted] •Two cost-effective imidazolium and pyridinium-based absorbents were successfully prepared.•The absorbent exhibited an uptake capacity up to 1159 mg/g towards methyl orange.•The adsorption behaviors were investigated combined with experimental studies and theoretical analyses.•Freestanding porous membranes were fabricated successfully by a step-by-step cross-linking process. Synthesis of adsorbents with permanent micro/mesoporous structures, tunable functional groups and processability is of great interest in industrial-scale processes for treating dye wastewater. Herein, a feasible crosslinking method has been employed to prepare porous ionic polymers (imidazolium and pyridinium-based) as adsorbents. The obtained materials have been utilized for the removal of methyl orange from aqueous solution and the maximum capacities of imidazolium-based adsorbents reached up to 1159 mg/g, which is superior to those of pyridinium-based ones and most known porous sorbents. The binding energies drawn from theoretical calculations based on density functional theory (DFT) proven the strong interactions between ionic units and dyes. Furthermore, freestanding porous membranes were fabricated from the adsorbents successfully by a step-by-step cross-linking process, implying their great potential in practical anionic dye removal.