Mussel-inspired polydopamine functionalized with ionic liquid as a novel, eco-efficient adsorbent for the selective removal of anionic pollutants from aqueous solutions

•Novel polydopamine-ionic liquid (PDA-IL) adsorbent was synthesized.•PDA-IL was used as an adsorbent for the removal of anionic pollutants from water.•Ultrafast kinetics and high reusability of nano PDA-IL was demonstrated.•Thermodynamic analyses indicate exothermic adsorption of ARS dye from water.•Electrostatic interactions, H-bonding and π-π stacking drive the adsorption.