Mussel-inspired preparation of MXene-PDA-Bi6O7 composites for efficient adsorptive removal of iodide ions

MXene has emerged as one of the most interesting two-dimensional (2D) nanomaterials, that has been widely explored for various applications, including environmental adsorption. However, the adsorption performance of unmodified MXene is poor and surface functionalization is necessary to endow new properties and improve the adsorption performance. In this work, we reported the fabrication of MXene based bismuth oxide (MXene-PDA-Bi6O7) composites for the first time through the mussel-inspired chemistry, which relied on the self-polymerization of dopamine to form polydopamine (PDA) films on MXene for subsequent immobilization of Bi6O7 nanoparticles. The utilization of MXene-PDA-Bi6O7 composites for adsorptive removal of iodide ions and the adsorption parameters on adsorption behavior were examined in details. The surface morphology, chemical structure and chemical compositions of these samples were characterized by a series of techniques. The results demonstrated that the maximum adsorption capacity of MXene-PDA-Bi6O7 towards iodide ions is 64.65 mg/g, which is obviously greater than that of unmodified MXene and MXene-PDA under identical adsorption conditions. In the fabrication strategy, the PDA could be facilely coated on the MXene and provide a platform for further immobilization of the Bi6O7 nanoparticles. This method is simple, easy of operation and can be occurred under benign and mild experimental conditions. Moreover, this method could also be utilized for introduction of other functional components on the MXene and thus multifunctional MXene based composites with designed properties and functions could be fabricated. We believe that this work will open a new avenue for fabrication of functional MXene based composites for environmental treatment.