Facile preparation of sulfonic groups functionalized Mxenes for efficient removal of methylene blue

Two demensional nanomaterials have attracted increasing research interest for various applications ranging from environmental adsorption, biomedical applications, catalytic degradation and energy storage owing to their high surface areas, facile surface functionalization . In this work, we demonstrated the preparation and environmental adsorption applications of 2D material MXenes through extracting Al layer from Ti 3 AlC 2 in a simpler and safer way. The surface of Ti 3 C 2 was modified with sulfonic groups via aromatic coupling-diazotization. The adsorption behavior and capacity of the Ti 3 C 2 and functionalized Ti 3 C 2 towards methylene blue (MB) were also examined and compared. The successful preparation of Ti 3 C 2 and modified Ti 3 C 2 was characterized by a number of techniques, including scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The influence of different experiment conditions such as contact time, solution temperature, pH and initial MB concentrations on the adsorption behavior towards MB were also examined. The results demonstrated that sulfonic groups functionalized Ti 3 C 2 (named as Ti 3 C 2 –SO 3 H) exhibited superior removal efficiency for MB. The maximum adsorption capacity of Ti 3 C 2 –SO 3 H towards MB is over four folds that of raw materials. The results of kinetics and isotherms studies demonstrated that experimental data were better described by pseudo-first-order model and Langmuir isotherm adsorption model, respectively. The process of MB onto surface of adsorbents was endothermic and spontaneous. Experimental details about pH indicated that the dye adsorption capability is favorable when the aqueous solution is alkaline. Based on the above results, cationic dye molecules were removed effectively by using Ti 3 C 2 –SO 3 H as adsorbent, which promotes the development of Ti 3 C 2 –SO 3 H for wastewater treatment.