Polyaniline-functionalized Nb2CTx Mxene composites for effective Cr(VI) adsorption from wastewater

In this study Nb₂CT_x/PANI nanocomposite was reported for the adsorption of Cr(VI) from contaminated water samples for the first time. The unique structure of Nb₂CT_x Mxene, combined with the conductive and adsorptive properties of polyaniline (PANI), forms a high-surface-area composite with enhanced affinity for Cr(VI) ions. The synthesized nanocomposite was characterized by using different techniques XRD, FTIR, BET, SEM-EDX, XPS and Raman spectroscopy. Influence of various parameters such as pH, dosage, and initial ion concentration on adsorption were also studied. Adsorption experiments demonstrate that Nb₂CT_x/PANI exhibits a high adsorption capacity, achieving a maximum Cr(VI)removal efficiency of 468.35 mg/g. Freundlich model is used to describe the experimental data of the adsorption system, where the calculated values of q_max agree with the experimental data, with a reasonable determination coefficient (R² = 0.876). The Nb₂CT_x/PANI MXene showed effective adsorption of Cr(VI)ions via multilayer adsorption, the mechanism involves electrostatic attraction, ion exchange, hydrogen bonding, surface complexation, and reduction. This study highlights the synergistic effect of Nb₂CT_x Mxene and PANI in developing high-performance adsorbents for heavy metal removal, offering a promising approach for environmental remediation.