Synchronously enhanced storage stability and adsorption ability of MXene achieved by grafting polyethylenimine

Abstract

MXene has great potential to remove contaminants from wastewater due to its abundant active functional groups. However, the application is greatly restricted by the instability of MXene, which is derived from its high oxidization property. In this study, a few-layer MXene was prepared via chemical etching, and then polyethylenimine (PEI) was grafted onto the MXene surface with the aid of glutaraldehyde-assisted crosslinking. The microstructure, storage stability, and adsorption behaviors toward water-soluble pollutants were systematically investigated. The results revealed that grafting PEI could promote MXene exfoliation and enhance adsorption ability. The modified MXene exhibited ultrahigh adsorption capacity toward methyl orange (MO) (909.1 mg g⁻¹) and hexavalent chromium Cr(VI) (1239.5 mg g⁻¹). Furthermore, the storage stability of MXene was greatly improved and almost no oxidization was detected for the modified MXene even after being stored for two months. This study offers a simple method to fabricate MXene-based adsorbents with excellent adsorption capacity and good antioxidant ability, and the application of MXene in wastewater treatment can be advanced.