Two-Dimensional Ti₃C₂T_x MXene Nanosheets for Efficient Copper Removal from Water

The performance of two-dimensional (2D) Ti₃C₂T_x MXene nanosheets in the adsorption and copper removal from aqueous media was investigated. Delaminated (DL)-Ti₃C₂T_x exhibited excellent Cu removal ability, because of their large specific surface area, hydrophilicity, and unique surface functional properties. Scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) analyses were performed to analyze the structural changes in Ti₃C₂T_x MXene and its interaction with Cu ions. Oxygenated moieties in the layered structure of MXene facilitated reductive adsorption of Cu²⁺ forming Cu₂O and CuO species. DL-Ti₃C₂T_x exhibited a higher and faster Cu uptake, compared to multilayer (ML)-Ti₃C₂T_x. The maximum experimental adsorption capacity (Q_exp,max) was 78.45 mg g^-1, and 80% of the total content of metal ions was adsorbed within 1 min. A pseudo-second-order kinetic model and the Freundlich adsorption isotherm accurately describe the equilibrium time and maximum Cu uptake onto the adsorbent material, respectively. Thermodynamic analysis revealed that the adsorption process was endothermic. The adsorption capacity (Q_e) of DL-Ti₃C₂T_x was 2.7 times higher than that of a commercially available activated carbon. The present results illustrate the promising potential of 2D MXene nanosheets for the removal of toxic metals from water.