Surface functionalization of MXene with chitosan through in-situ formation of polyimidazoles and its adsorption properties

Abstract

In this work, a novel imidazoles-MXene hybrid composite, namely polyimidazoles chain overlaying on the surface of MXene (Ti₃C₂@IMIZ), was prepared by a simple method. Through this strategy, imidazoles can be in situ growth on the surface of MXenes via a facile multicomponent reaction using chitosan as a renewable reactant. Based on the characterization results, we demonstrated that a thin layer imidazoles with an ordered chain structure was embedded on the surface of Ti₃C₂, which resulted in the formation of a novel imidazoles-MXene hybrid composite. The adsorption performance of Ti₃C₂@IMIZ for removal environmental pollutants was evaluated using heavy metal ions of Cr(Ⅵ) as adsorbate. Detailed adsorption characteristics of Ti₃C₂@IMIZ including operational factors, adsorption kinetics and isotherms models were investigated. XPS analysis showed that Cr(VI) was converted to Cr(III) with low toxicity during the adsorption process. The adsorption of Cr(VI) and reduction of Cr(VI) to Cr(III) contribute to elimination of Cr(VI) species. The adsorption behavior and process analysis show that the adsorption mechanism is mainly physical adsorption through electrostatic interaction. The excellent reproducibility suggests that Ti₃C₂@IMIZ may be a potential candidate for remove of Cr(Ⅵ) in actual sewage treatment.

Keywords: Adsorption of Cr(VI); Chitosan; In-situ growth; MXene-based composites; Multicomponent reaction.