Mechanistic and Kinetic Evaluation of Hexavalent Chromium Adsorption Using Polyaniline‐Functionalized Ti ₃ C ₂ T _x MXene Composite

In the past few decades, different efforts have been made toward chromium (VI) removal from wastewater. In this study, a Ti 3 C 2 T x /PANI composite was synthesized via in situ polymerization from (PANI) and Mxene (Ti 3 C 2 T x ). The composite was characterized using XRD, FTIR, SEM–EDS, XPS, and Raman spectroscopy. FTIR spectra revealed characteristic functional groups of both Ti 3 C 2 T x and PANI, with significant shifts and intensity changes upon Cr(VI) adsorption. EDS and XPS also showed the presence of Cr after adsorption. Raman spectroscopy further verified PANI polymerization and Cr(VI) adsorption. The adsorption performance for Cr(VI) is markedly influenced by the pH level of the solution, with optimal adsorption occurring at an acidic pH. The experimental findings showed good agreement with the Langmuir–Freundlich and Khan isotherm models, while the pseudo‐second‐order and MESO kinetic models best describe the adsorption process. The Ti 3 C 2 T x /PANI composite exhibits a high adsorption capacity of 342.5 mg g −1 and good stability, maintaining its adsorption efficiency over seven cycles. The adsorption mechanism involves electrostatic attraction, surface complexation, and physical adsorption. Notably, the developed Ti 3 C 2 T x /PANI composite exhibits a considerably higher Cr(VI) adsorption capacity than most previously reported MXene (Ti 3 C 2 T x ) and polyaniline (PANI)‐based adsorbents. This superior performance is attributed to the synergistic interaction between the conductive polymer PANI and the high surface reactivity of Ti 3 C 2 T x layers, which enhances active site accessibility and electron transfer during adsorption. The findings demonstrate the composite’s potential as an efficient and robust adsorbent for Cr(VI) adsorption.