Removing Cr(VI) from aqueous solutions using a functional ionic liquid-based cross-linked polymer

• The functional ionic liquid-based cross-linked polymer of PDVB-IL was prepared.
• PDVB-IL effectively removes Cr (VI) from Cr (VI)-containing solutions.
• PDVB-IL has a high adsorption capacity in a short time.
• Adsorption of Cr (VI) on PDVB-IL is favored at low pH.

A novel functional ionic liquid-based cross-linked polymer was synthesized from 1-aminoethyl-3-vinylimidazolium chloride hydrochloride and divinylbenzene. The physicochemical properties of the adsorbent were investigated using scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The adsorption capacity of the novel cross-linked polymer with respect to Cr(VI) was investigated using a batch adsorption procedure and the kinetics and thermodynamics of the adsorption process were further investigated. It was found that the adsorption kinetics was well fitted by a pseudo-second-order model and the adsorption isotherms agreed well with the Langmuir model. The maximum adsorption capacity after 5 min at room temperature (25 °C) was found to be 391.4 mg/g, which was much better than the most of the previously reported adsorbents. The adsorption process was found to be dominated by electrostatic interactions. The introduction of functional ionic liquid moieties into cross-linked poly(divinylbenzene) polymer constitutes a new and efficient kind of adsorbent.